Sinclair User - DigitalOcean

£1.95

s inclairu s e r

6•11111n t C O M P O IA M M M I L

1984

TOP ADVICE FOR ZX OWNERS.‘Juyers' guide to best software and hardware.

Sixteen pages of superb programs.1983 REVISITED

Choosing which game to buy from the mountain available is a difficult job,especially when everyone claims to produce the best on the market. But how can

you tell the best from the rest?. To help you decide, read on.

THE DUNGEON MASTERLet your Spectrum be your guide in a totally newdimension in adventures in the true spirit oftraditional role playing games where YOU designthe scenario_"I have been a Dungeons and Dragons fan forseveral years_The package provides excellententertainment for all fans of the cults and shouldprove a good introduction to the game".

....Sinclair User."Highly recommended for its versality, originalityand quality. Definately well worth obtaining".

Computing.ZX Spectrum allik E 7 . 5 0

Written by Graham Stafford,

INVASION OF THEBODY SNATCHASI

At last' a version as fast and furious and asfrustratingly addictive as the arcade original.Landers, Mutants, Bombers. Pods, Swarmers andmuch much more combine t o produce theultimate space game'ZX Spectrum 48KWritten by Simon Brattel and Neil Mottershead.

Please send SAE for our latest catalogue anddetails of our forthcoming software.Catalogue FREE with every order. PIP includedPlease add E0.50 per item for overseas orders.Please make cheques/PO's payable to:CRYSTAL COMPUTINGDept SUl l

, 2 ASHTON WAY

\ . _

' . EAST HERRINGTON- SUNDERLAND SR3 3RXN.._

What thereal critics say.

Very rarely havesoftware titles producedsuch universal acclaimas 'Halls of the Things'

and The DungeonMaster'. Now, with threebrand new programs,

Crystal continues to setthe standard of software

excellence. Thedifference is obvious-

the choice is yours:

THE ISLANDThe ultimate test of logic and deduction! Can yousolve the hidden mysteries of the South PacificIsland on which you have been stranded' andescape alive' A brilliant classic style adventuregame to facinate and frustrate you for months'ZX Spectrum 48K e 7 . 5 0

Written by Martin H. Smith_

HALLS OF THE THINGSA stunning multi-level maze 'arcade. adventure*."Excellent and dangerously addictive - couldchange t h e S pe c t r um g a m e s - sceneovernight". _ S i n c l a i r User."Spectacular • One of the best games I've seen,finely bal anced be t w e e n simpl ici ty a n daddictiveness - superb graphics and colour ICAN'T RECOMMEND IT HIGHLY ENOUGH,

_Popular Computing Weakly.ZX Spectrum 4116K e 7 . 5 0Written by Nell Mottershead, Simon Brattel and

Martin Horsley.

ROMMEL'S REVENGEA brilliant Interpretation of the most visuallystunning arcade game of all time. Superb highresolution 3D graphics with full perspective plusa host of new and exciting features makeRommers Revenge the most spectacular gameever produced for your Spectrum'ZX Spectrum 418K t 6 . 5 0

Written by Martin Horsley.

DEALERS? For details of our excellentdealer di scounts (I ncl udi ng •xpor t iring Chris ClaMe on 061-205 6603.

PROGRAMMERS! Wr i tten a n y goodsoftware? send it to us for evaluation anddetails of Our excellent royalty scheme.

Please Supply :invasion of the Body Snatches 0

Rommers Revenge D Th e Island DHalls of the Things D Th e Dungeon Master C

Catalogue (please enclose SAE Sin. x ginsienclose cheque/PO for.

NAMEADDRESS

SUA

sow, sEcoavbsinclairu s e rThe4awett n CooPentManaging editor

Nigel ClarkDeputy editorNicole SegreConsultant editorMike JohnstonManaging production editorHarold Mayes MBESoftware editorJohn GilbertProgram reviewerRebecca FergusonIllustrator/designerBrian KingGroup advertisement managerJohn RossSales executiveAnnette BurrowsProduction assistantDal EpammondouManaging directorTerry CartwrightChairmanRichard HeaseSinclair User Annual is publishedby ECC Publications Ltd. I t is inno way connected with SinclairResearch Ltd.TelephoneAll departments01-359 3525If you would like to contribute toany of the Sinclair User group ofpublications please send programs,articles or ideas for hardwareprojects to:Sinclair User and Programs,ECC Publications,196-200 Balls Pond,London NI 4AQPrograms should be on cassette andanicles should be typed. We cannotundertake to return them unless astamped-addressed envelope isincluded.We pay E10 for the copyright ofeach program published and .L50per 1,000 words for each articleused.

Copyright 1983Sinclair UserISSN No 0262-5458Printed and typeset byCradle), P r in t PLC ,

Warley,West MidlandsDistributed bySpotlight Magazine Distribution Ltd,1 Benwell Road,Holloway,London N701-607 6411

CONTENTS7 N E W S

A review of the important events in 1983 including the launch of the Microdriveand a knighthood for Sir Clive Sinclair.

11 S O F T WA R E SCENEThe best guide to all that is available for the Sinclair machines.

39 H A R D W A R E WORLDStephen Adams gives his views on the peripherals which are now available.

45 P R O G R A M M I N GA complete series on how to write in Basic.

61 I N S I D E SINCLAIRBehind the scenes at Sinclair Research.

73 F U T U R O L O G YLooking into the future and seeing a large demand for the microcomputer.

81 B O O K SJohn Gilbert investigates publishing in 1983.

85 P R O G R A M PRINTOUTSixteen pages of the best programs of the last year, plus two more.

105 H E L P L I N EAndrew Hewson and the pick of his regular columns.

117 U S E R OF THE M O N T HMeet the people who find unusual uses for their machines.

131 M E M O R YFind the best way to expand your RAM.

SINCIAIR USER Annual 1984 3

BLACK CRYSTAL

The Classic, si t program adventure game for the 48K Spectrum and l o l l.Z I C - 1 1 1

computers. No software collection is complete without it."SLACK CRYSTAL is an excellent graphics adventure and a well thought out

package" ['Sinclair User, April Al i .CK CRYSTAL has impressed me by its sheer quantity and generally highof presentation. I am afraid I have become an addict" 'Home ComputingApril '831.

45K 180K of program in six parts o n l y 17.507X-81 loK over 100K of program in seven par ts. . , m1417,50

Why pay more lot less of an adventure?

THE ADVENTURES OF ST. BERNARDAn exciting_ fast moving, machine code, arcade game when y ou guide your

St. Bernard through the perils of the icy wastelands to rescue his Mistressthe clutches of the abominable snowman. INK Spectrum L5.Q.5,

THE CRYPTwritten by Stephen Renton

Prepare yourself for lite many challenges that shall confront you when you dare.;itet enter "THE (RI P E '

You will batik with giant scorpions, Hell spawn. Crane's. Poirhiego and if youare unlucky enough — the Dark Cyclops in this arcade style adventure.Available now for the 45K Spedrom E 4 . 9 S

ZX-11 COMPENDIUM

Alien Intruder, Wimples Adventure, Numerology, Hangman, Hieroglyphics.Movie Mogul

The ideal software package lot all loK ZX 4 I owners. Six major programmes ontwo cassettes for only X6.50.

"Mien Intruder Hieroglyphics — Both programs make good use al graphics andwords to make a very entertaining package." iSinclair User, Aug '521

"Mien Hieroglyphics Wumpus Movie — A varied mix from Carrell all leaturIns imaginative responses and graphics and all of them good games for all apes(Hieroglyphics is particularly good for children)." iPopular Computing Weekly.Aug '821

STARIDIUCE ONETake on the robot guardians of the central computer in a superbly stylised three

dimensional battle game. VW Sp., num E5.tosilooq. MACHINE CODE ARCADE AcrioN1

THE DEVIL RIDES IN

uttered the last incantations as the clock struck thirteen. All tell silent except fora taint rustling in the corner. From out of the shadows they came. all Ht4I's furyagainst me but I was not defenceless until the Angel Of Death, astride a wingedhone. joined the battle. Avoiding his bolts of hell fire. I took careful aim. Mychances were slim, but if my luck held • l a K Spectrum

Iraq moving, machine code, all action. Arcade game.

on

nd

ur-gesly,

A% Ailatoht through most good computer stores or direct from:Carnal Software Ltd. North Wrylands Industrial Estate, Molesey Road, Her-sham, Surrey KI I 2 3PL.Deakrs: Contact us for our nearest wholookt.

ILL SO A R E

COMING SOONI ItIE WRATH OF MAGRA

The first horn has been destroyed. The Black Crystal of Beroth has been banished.The alliance of Evil has been defeated by the armies of Lord lemial. So ends theThird Age. Now we invite you to write your name in the history of the Fourth Ageof the Third Continent.

You will meet friends and enerrics ol d and new, in the long awaited sequel toVokamic Dungeon. Using high resolution graphics and combining the best qualitiesof "BliscloCrystal" and -V o l c a n i c D u n g e o n • . w e w i l l a l lo w y ou to b e co m e p ar t of

this tale of revenge."The Wrath Of Viagra" comes ail three, lielt programs on cassette. nosed with

heramctiori manual and book detailing the history of the Third ContineM and themany spells you will be using throughout the game.

NOTE: T h e Wrath O f M a r a- i s a c o m p l e t e a d v e n t u r e. Y o u u s ed n ot b us y

"Volcanic Dungeon .kr Black Crystal" to play it_

W i s l a\tacitt-its tor Sinctair addicts

*

t,ctegly tetYJ 000povdest Wise 01

All Me le atutes ot tne Powo Base plus buitt-in

; I t v enable_rnazin sound arriplitier Set SPBAA g value at ONLY 119•95

Ine great Spectrum sound cn p rover

SUPER SOUSE) SPEC. OAPrai • Fully adtustable Spectium SOund PonOtilei• Simply plugs oto s o O k e t

• S e t SSS 1 7 00 lPP3 Batten' 'included) ,11;

s so good, O ve shou‘d Note thought oi ittla u . . 1 2 ° L . 0

2 0 j , 0 m1° C l u"

ot this indispensable unit compiete vow' coroputet.Pal nave SAVEILOAD and ON/ OFF svvitching and a

Sri( vetsions

Set SPA Fully variable sound atop - 3 v. A3 arnp sockkets,Ville% and neon ln&catot - cable and plug • • • • 1 2 7 . 5 0

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Set. BP3 - as BP but no sound • • .......•••... 1 50Bet BP.% a s k u t no sound ot socttets 0 3 . 0 5Ret BP5 - VABA version sockkets , Mains Vitenneon. cable and plug • •. ........... • • • • ..... ....• • ..... 120i=kel BP6 as BP& but no cabte of socWets _, • • 1 A 2 BS

• Guts out weal and teat on Ougs andsockcets • SWitcning tot SP1/4\10.0and 9 vottsN S S 1 99 5

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Spectsurn Set N7.)03A Set S O 19 15

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t frAKEV/4 000 WOBBLE91://t/t/l>.' S I OPPER

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Flat-. Set SVJ 15 25. lilted. Bet SINN 0•25Elttra Song iot ponlpl -- Oat Set * I E5 75 loted Set LINti cf) 75

Et. 11'6166:WIRELESSVI OS1(5141100• Woos ON I OFF switch • 4i, ‘3 VW sockkets instde• Supterne gualitV • At\ wires StoNN aolaV• Carnting handte • Easlly stoted • Sturdilybuilt in stove enamelled &Leek

• tdeal tot scnools • Suitabte totmost micros including Str ide and BBC

• Acres ot room tot all peripheralsDesk( top Model Set CVIIA E49.00

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laWes trie neat out Cot your' comSpedttum or putet.

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101 Set l'AC ZA1 ,65 Speartir0 fket SC 1AA•135Separate Cool-it Unit

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Spectt . • ... .......................... Beum only) i SPWC 125.00Back', ? ackt1 . ...... ... .................... _...,.., Bet BP A C 1325Backk Pactk 2 •••• ..„ .................... .....-,, Bet BP2C f24 .5

Sound ?owe! Base

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................... .. • • • ..... BeN BP AC 11B.. - . ..... . Set BP5C 126Set BP6C 11 BA

• ON,' OFF switcn tor instant scteenclearing • 1_0 / SAVE switch• All votes included • Angled

lot easier use • Saves wear andteat on connections • Seal value tor moneySpectrum Set PBSA 113.50 2.01 P B 0 . 1 113.00 •

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13NINIaceVarPsaavcVturn. .......... . . . .. • • S e t NHSSC

Back( Pact( . . .Badc Packt 5 . . . . . . . . . ..........

BO

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SINCLAIR USER / Noma/ 1984

•

Newsp i k K A *3 .1'r " .

The last year has been another eventful onein the Sinclair market. The arrival of the

long-awaited Microdrive and a knighthoodfor Clive Sinclair are only two of the items

we cover in this assessment of thedevelopments of the 12 months.

SINCLAIR USER Annual 1984 7

8

Mike Johnston reports on last year

Market reachescritical massIF YOU GATHER sufficient radio-

active element together, at a certainpoint it reaches a critical mass and a

chain reaction follows. Something simi-lar seems to have happened with thedensity of home computers in the popu-lation early last year. Suddenly every-one seemed to want a home computer.

Computing was scarcely a minorityinterest even before that, with an esti-mated half-million home micros in usein the U .K . in 1982 but in 1983 i tcaught the public imagination. Com-puting became news.

The Sunday newspaper colour sup-plements contained features on comput-ers, the daily papers started computercolumns, young programmers w erehailed as the new pop stars and, perhapsmost fittingly, Clive Sinclair, the manwho invented the home micro, receiveda knighthood.

While micros in general began toreceive increased media coverage, SirClive and his company were rarely out

of the news. In December, 1982 a strikeat one o f the Sinclair subcontractingplants, T i m e x i n Scotland, m ad enational headlines. In January the saleof 10 percent of the company to Cityinvestors for £12 million and the newsthat Sinclair Research was worth £130million practically guaranteed morecoverage.

In March S i r Clive was namedYoung Businessman of the Year by TheGuardian. I n April there were moreindustrial relations problems at Timexand the development of the flat-screenTV project was affected. The Spectrumprice reduction in May made headlinesas the first colour computer for less than£100 — the 16K version sold for £99 —and the June announcement i n theQueen's Birthday Honours of a knight-hood for Sir Clive made even biggerheadlines.

Later that month the Sinclair plan fora high-technology think-tank again at-tracted the national press. In August,

the final release of the Microdrive wasjust a little of an anti-climax — after'coming shortly' for 18 months — butthat was capped in September by theunveiling o f the flat-screen T V , firstannounced even earlier.

Sales of the Spectrum soared duringthe period, perhaps helped by all thepublicity, from 60,000 in November,1982 to more than half-a-million byAugust. The ZX-81 may have done lesswell, although no figures have beenreleased, despite the considerable pricereductions — down to £40 in May andagain down, including 16K, to £45 inAugust. Sinclair is continuing to sup-port the machine but the W H Smithannouncement that i t would not b estocking any new titles for the ZX-81 isperhaps ominous.

Sinclair has not had the field entirelyalone, as he did in the early days, andthe less-than-L200 market has becomeincreasingly crowded i n the last 1 2months, with some fierce price-cuttingtaking place as companies jockeyed for aplace.

The Vic-20 fell from more than £200to around £140 in some shops beforelast Christmas and other companies fol-lowed suit — Texas, Atari, Lynx, Drag-on — either by reducing the price oroffering a machine as part of a packageincluding software or other hardware.

After Sinclair reductions in the priceof the Spectrum in May, there was afurther round of cost-cutting from othermanufacturers. All o f which has beengood news for the consumer, who nowhas a much wider choice at lower prices.It has not been such good news for somecompanies forced to reduce their profitmargins to compete with the Spectrumwithout the advantages large-scale pro-duction brings.

Despite the competition, the Spec-trum has managed to maintain a healthylead over its rivals and continues to topthe best-selling hardware charts. By theend of March, the company was report-ed to have doubled its turnover from127 million to £54 million and made aprofit of £14 million before tax.

In the U.S., where competition hasbeen even stiffer, a number o f largecompanies, including Texas Instru-ments, Atari and Mattel (Aquarius) hadsubstantial losses. Timex, which makesSinclair lookalikes, has not done toowell either, despite a promising start.The TS2000 (Spectrum+) was due forrelease early in the year but was de-layed, then re-designed t o meet thecompetition. Timex was forced to makeheavy discounts on the TS1000 (ZX-81)to boost flagging sales.

SINCLAIR USER Attnidai 1984

l4

-'PlaywithaGriffinSo they -ake school in their stride

•

Your children are using a computer at school farmore often than you think

Computers make learning an absorbing gameand retain a child's interest and participation.

Griffin Software have selected and adapted forhome use a series of Griffin educational softwaretitles already used in schools_

The first six titles suitable for 4 to 8 year olds.are available now

If you have a Z X Spectrum 48K or a BBCModel B microcomputer at homeyou can so easilykeep up the school's good work And the beauty ofIL is, the child sees it as a game

Wordspell helps withspelling; Tablesums unravelsthe mysteries of tables;Fairshare uses 011ie theOctopus to make sense ofdivision; Numberfun makesaddition and subtractioneasy; Wordgames helps withspelling and expands vocabulary: and with Getseta child is helped with counting,

All good fun!Griffin Software titles are at W Smith.Boots.

and other computer shops everywhere.

o n ly t 709each to unt the X Spectrum 4RK O n l y 1:9 95 earh tai Autr the AB( B

& Me/G RI FF IN

SOFT WAREit's an education.

One advantage the Spectrum has con-tinued to enjoy i s a very large andsophisticated software base. Many com-panies which produced software for theZX-81 have found i t easy to make thetransition to Spectrum software. Othercompanies from the record and publish-ing world — Thorn-EMI, CBS, Virgin— attracted by the large potential mar-ket, have also joined the contest.

The number o f new software com-panies, large and small, to have joinedthe Sinclair industry i n the year i sastonishing. They are almost as numer-ous as the new computer magazines —two new weeklies and innumerablemonthlies which appeared during theyear. A feature of the last year has beenthe movement into software. Compan-ies once specialising in hardware, likeQuicksilva, dK•Tronics and Kempston,have begun to market programs. Quick-silva ceased production of hardware en-tirely.

Software has become increasingly bigbusiness with the one-man program-mer/entrepreneur giving way to thepublishing software house which com-missions programs from freelance pro-grammers or employs full-time softwareproducers. In recent months computermagazines have been ful l o f advertise-ments fo r programmers and/or pro-grams, preferably in machine code.

A number o f companies now havelarge minicomputers which behave likeSpectrums — or Orics or BBC machines— but which offer many additionalfacilities for developing software. Psion,which had a £5 million turnover lastyear, produced Fl ight Simulatorusing such a machine; MelbourneHouse developed The Hobbit in thatway; and Ultimate devised PSST.

More recently, Virgin Games dedared its intention to use such a systemin preference to commissioning pro-grams. While i t i s sti l l possible, nodoubt, for someone to run a part-timecompany from a kitchen table, thosedevelopments make i t more difficultbecause of the users' demands for well-finished programs and the costs nowinvolved in marketing.

It is an indication o f the size andpopularity of the computer market thatit is beginning to attract crime. Threethousand Spectrums, later recovered,were stolen from Prism Microproducts,the Sinclair retail distributor, in June. Ithas also become profitable to pirate andmass-produce popular games tapeswhich are then passed-off as originalsfrom the major software houses.

Another issue which has enragedsome software companies is the one of

software libraries. In March, Quicksilvaapplied for an injunction against a com-pany it claimed was effectively lendingQuicksilva programs, which might easi-ly be copied.

It is an indication o f the seriousnessof software companies and the largeamounts o f money involved in fraudthat two organisations have been set up,The Computer Traders' Association inFebruary and the Guild o f SoftwareHouses. Bo th claim t o b e seekingmethods of protecting the customer andpolicing the industry.

Methods o f distribution h a v echanged, too, and have become better-organised. Mai l order is stil l popularbut many users prefer to see in advancewhat they are buying, without having towait. More and more, software is beingdistributed through wholesale and retail

'Companies oncespecialising in

hardware have begunto market programs'

outlets. P r i sm Microproducts h a sreached an agreement with an electricalretail chain to establish software dis-plays in the shops, which wil l be re-stocked regularly by Prism. It is hopedto extend the system to other retailers.Prism also hopes to introduce electronicdistribution o f software via a terminalheld by the retailer.

Another new development fo r thedistribution o f software appeared this

year, after two false starts. Micronet800 produced an adaptor which allowsthe Spectrum to be linked via a tele-phone line to Prestel and to the Mi-cronet programs and information onmicros. It also opens the possibility forSinclair users to contact each other viathe system.

Star item this year, though, was thefabled Microdrive and Interface One,which finally surfaced in August afternumerous false alarms. I t was almostbound to be little disappointing, consid-ering the length o f time we had toimagine how wonderful i t would be.Having said that, there is little doubtthat i t will be reasonably high on theshopping lists of most Sinclair users foradd-ons; 85K o f program loading in amatter of seconds must be worth wait-ing for and for most o f us the wait islikely to be some time.

The only serious reservation is theprice o f the cartridges. The interfaceand networking look ideal for use i nschools and may go some way to upset-ting the near monopoly o f BBC ma-chines. That was one area where theSpectrum has not been too successful sofar this year.

The other major piece o f hardwarefrom Sinclair appeared at the PersonalComputer World Show. The InterfaceTwo seems to be designed specially forthose who can admit that they did notreally buy a computer to work outquadratic equations at all. A joystickcontroller w i th plug-in R O M ca r-tridges, it allows instant access to yourfavourite games programs with a mini-mum o f fuss. The Interface is pricedvery reasonably at around a ° but thegames cartridges are a little more ex-pensive at around f, 15 each.

SINCLAIR USER Annual 1984

Software Scene

An important part of Sinclair User is thereview of the latest software. Our writers

give their opinions on the best available forboth the Spectrum and the ZX-81.

SINCLAIR USER Annual' 1984 I!

12

John Gilbert's overview

is 'astonishing'THIS YEAR the software indus-

try has been very fortunate inhaving more rises than falls ,

although in most cases that is due toluck and the market s ituation ratherthan good software. The rate of devel-opment and achievement by some soft-ware houses has been astonishing attimes. I n the adventure sector T h eHobbit swept the board for accolades.Arcade software Time Gate, 3D Com-bat Zone and now Maz iacs, havestood, out from a bewildering array o fspace and maze games.

The Hobbit sent thousands o f 48KSpectrum owners mad and floored mostcritics, who could not get enough of it.Many critics thought, when it was firstreleased, that there would be manyimitations. The critics were wrong asthere are some companies t r y ing t oequal the game but no-one has managedto capture the same atmosphere of mad-ness.

As with adventure games, arcade soft-ware has reached a peak. T h e yearstarted with John Hollis ' T ime Gatefrom Quicksilva whic h showed whatcould be done with the graphics capabil-ity of the Spectrum. Particular attentionwas pa id t o t h e three-dimensionaleffects used in the program and, as anearly effort, Time Gate was stunning.

Another game which shows-off thegraphics o f the Spectrum is Halls o fthe Things from Crystal Computing.It stretches t h e Spec trum graphicsfacilities to the l imit and provides anincredible chase round a multi- levelmaze, populated by strange and deadlycreatures.

The game has proved popular withmany people although, for some reason,retailers seem reluctant t o s tock i t ,From the moment it is LOADed, Hallsof the Things displays signs of technicalexcellence. I f you watch closely you willnotice something unusual happeningwhen the t it le screen enters the com-puter. The display does not appear inblocks on the screen. It appears to movevertically straight down until it hits thelast line o f main screen and then thegame begins. There is no wait betweenthe LOADing of the initial display andthe game.

•

It is surprising that no manufacturersof software have tr ied to duplicate theefforts o f Crystal, although one game,Maziacs from dK'Tronics, is close to it.It also relies on speed and graphics forits appeal. A good deal of thought obvi-ously went into the visual presentationof Maziacs and because of that i t is anattractive package.

A new type o f game to emerge in1983 was the graphics adventure. Unt ila short time ago most adventure gamesused text only to describe the locationswhich could be visited by the player.The Ar t ic adventures prov ide goodexamples of this type of game.

The new class o f adventure useseither full-screen to illustrate locationsor split-screen with text at the bottomand a picture of the current location atthe top.

The fi r s t graphics adventure wasPimania, although i t differs s lightlyfrom the strict definition of the categorybecause the locations are not displayedusing graphics. The animated graphicswhich are used, inc luding the Pi-mansinging, give clues to the solution to thepuzzles which are posed in the text, oran admonition to the player who is notdoing very well. There has been unmis-takable reac tion f r o m players—youeither love it or you hate it.

Apart from Pimania, the first graph-ics adventure for Sinclair machines wasThe Black Crys tal from Carnell Soft-ware. I t provided the basis for severalsimilar games where the locations wereput on to a screen map and the playermoved a marker around it.

The next development of this type offormat was provided by Dor ic Com-puter Services which produced a Spec-trum version of The Oracle's Cave.The bottom o f the display is taken-upwith a description o f the cave systemwhich you are in and the top contains asilhouette picture of the cave and yourplayer-figure in the cavern.

That fi gure w i l l walk and c limb,depending on what you are asking it todo, and the whole scene is very lifelike.The graphics are smooth, startling andexciting. T hey show the way for thedevelopment o f the graphics adventurein the next year.

Unfortunately the business and n market is not much further alongedu-

cation

Development rate itis too soon to visualise what compan-

ies are likely to do with the Microdrive

the road than it was at the start of 1983.

but manufacturers already in the busi-ness have made a good, i f slow, start.

Most o f the products produced in thelast year have been for the home financemarket and, include Finance Managerfrom O CP and Business Accountsfrom Wi ls den Computer Serv ices.Little has been produced but the pro-ducts available are of good quality.

The main contributor to the smallbusiness market is Hilderbay, whic hstill produces a Stock Control Pro -gram and Pay r o l l program fo r theSpectrum and ZX-81. Hilderbay is anexception to the rule, as it also producessoftware for other more expensive com-puters, such as the Apple II, and so hasthe experience to produce the propertype of program.

Another company t o edge its wayinto the small business sector is Kemp.It has provided businessmen with threevery usable programs—Purchase Led-ger, Stock Control and Stock Led-ger. Unfortunately they are availableonly for the 48K Spectrum.

No doubt programs o f this k ind willsoon have Microdrive upgrades but un-til then they are o f somewhat limiteduse for anything but small businesses.

There is lit t le worth noting in theeducation field this year, except for theMEP programs from Sinclair Research.Sinclair took the unusual step of adver-tising the programs as ones which w illbe used in schools and can be bought forhome use.

One company moving to the fore thisyear, not because it retains any really

SINCLAIR•USER Annuai

outstanding programmers but becauseof the simple brilliance of the teachingtechnique which is used in the pro-grams, is Widget Software. It has pro-duced several educational programs butone of the most exceptional is Path-finder. The cassette contains fourgames based on different mazes. Theidea is to learn as you play—an import-ant lesson to be learned by all edu-cational manufacturers.

Young people learn more easily by •playing games, so Widget has concen-trated on combining educational con-cepts with play. Although the programsare written in Basic, they perform the

dual task of teaching and keeping achild interested very well.

Education is another area in whichthe Microdrive will be useful. I t ispossible to store information, graphicsand questions on Microdrive which canbe called up by a teacher or a student.In that way it will be a valuable tool andeducationalists would be advised to takeadvantage of it.

It is too early to see the effects of theMicrodrive, Interface One, or even tosee what impact Interface Two willhave on the Spectrum. Interface Twowill contain a ROM cartridge systemwhich will allow users to plug in cart-ridges similar to those used with Atarimachines. That will give instant access

SINCLAIR USER Annual O M

to games and utilities as soon as themachine is switched on.

Next year there should also be aradical change in the way software de-velops and how it is accessed. Softwareon Microdrive and on ROM cartridgeare only two new items. The third istelesoftware which can be accessed fromMicronet 800.

Telesoftware can be accessed from acentral database of programs via tele-phone lines. The programs are trans-mitted or downloaded from the databaseand can then be listed on the user'scomputer. A t present the service isavailable only for the Spectrum but

'Now that 48K Spectrums are beginning tofilter into schools, children will lose the attrac-tion for games and begin to treat computers,and the software which they run, as tools'

Micronet plans to make it available forthe ZX-81.

Some people regard telesoftware as athreat to mail order and to cassettesoftware. Those arguments are not logi-cal nor will they be pertinent in a fewmonths. Mail order seems to be dyingand the retail shops, such as W HSmith, are taking-over the sale of cas-sette and disc-based programs. Becauseof the easy availability of those pro-grams, cassette software will be with usfor a long time. After all, not everyonewill not want to buy a Micronet adapt-or. It is rather like saying that every-body who wants a video will not want towatch live television.

The Sinclair software scene hasundergone a massive change this yearbut that is nothing compared to whatmay happen in 1984. Now that 48KSpectrums are beginning to filter intoschools, children will lose the attractionfor games which they had initially, andbegin to treat computers as tools whichcan be used for a purpose in everydaylife. Demands for games softwareshould recede slightly and the educa-tion, and eventually business, marketshould benefit from that.

Children will still have an initialfascination with computers but thatshould turn to understanding now thatmany schools are geared to computerscience. While 1983 has been a year ofconsolidation of the market, in 1984there will be an expansion of the moveswhich have already begun for practicaluses on the Spectrum and still, to somedegree, the ZX-81.

SinclairaccountsJohn Lambert

THE SPECTRUM and ZX-8I

have no reputation for beingserious business computers but

they are built around the same centralprocessing unit as many grander ma-chines and can perform all the functionsrequired of a business computer systemby a small — or not so small — business.The high-quality software necessary forthe purpose is becoming available tomeet the needs of an ever-expandingmarket and the recent appearance of themuch-vaunted Microdrive for the Spec-trum promises to rival some of thebigger disc-based systems. With the ad-dition of a full-size printer and inter-face, your computer can deal with youraccounts, filing system, word process-ing, business planning and payroll andproduce results of a professional stan-dard.

To be fair to Sinclair, its machineswere not designed with the businessuser in mind but rather to be a low-costintroduction to computers in the home.In that it has undoubtedly succeededbut it imposes certain limitations, themost noticeable of which are lack ofmemory and data storage.

Memory, however, should no longerbe a problem, given the large number ofadd-ons on the market, and the Micro-drive provides quick and easy access tolarge amounts of stored data.

The Sinclair keyboards have attract-ed criticism but again if the user findsthem a problem a number of full-sizekeyboards are available. The screen dis-play can also pose a problem, 32 charac-ters per line often not being sufficient toproduce the required display, but bycareful programming the software caneither give up to 64 characters or allowthe user to output to a full-size, 80-column printer. Ultimately using a Sin-clair machine in business will not be thesaint as using a large, dedicated ma-chine, but different does not necessarilymean worse.

Accounts programs lie at the heart ofa business system. They give the busi-ness user a powerful tool in the runningof a business where at the touch of abutton a list of debtors and creditors canbe called-up or even a set of accountsproduced. In that way it is possible to

13

1 4

keep far greater control over affairs.Having decided to operate a computer-ised accounting system, users must firstdecide which program to buy.

There, unfortunately, th e y mustmake their choice. There are many onthe market ranging in price from aboutLIO upwards and each will perform inslightly different fashion. I f possible,the user should take an account to oneof the bigger computer shops to try theprograms or i f that is not possible tocontact the software house direct.

Firms such as Transform Ltd or Hes-tacrest L td both supply a range o fprograms known technically as a suite— for both the ZX-8I and Spectrum —and Gemini, which produces a suite forthe Spectrum, will be ready to guide theprospective buyer through the maze o fsoftware and hardware available.

Having bought your program youshould not have to spend hours learningan alien subject. Your computer pro-gram will take you step by step througheach stage by a series o f prompts andmenu selections. There are two import-ant things to remember. First, garbagein, garbage out — i.e., i f you enterincorrect data, do not expect the com-puter to read your mind. That is howyou can send bills for £0.00. Second,always make a back-up copy o f dataentered. Normally that is done by thefather-and-son method, where two tapesare used alternately so that, shouldthere be a power cut or some otherdisaster, you will always have an up-to-date record of your data.

Computer-generated invoices are al-ways impressive and generally less time-consuming t o produce. Ta ke f o rexample, the invoicing program fromTransform Ltd. Initially you would en-ter a l ist o f your clients' names andaddresses, together with your own, andthen whenever you wished to send aninvoice/credit note you would have toenter only the first three letters of thename for the computer to find it.

The computer also takes care o f allthe calculations o f VAT, pricing andthe various forms of discount, i.e., tradesettlement and the like. Having arrivedat the total, it will give you the option ofprinting as many copies o f the invoiceas you wish, even pausing to allow youto change the paper in the printer whennecessary.

At any time you can print a list o foutstanding invoices or print your state-ments. Additionally the program wil leven print-out your address labels butthat facility will be examined later.

Purchase/sales ledger are the mainaccounting books of any business and as

such are catered for by a number o fsoftware houses, notably Hestacrest,Transform, Kemp and Gemini. TheCash Book program by Gemini for the48K Spectrum offers the user some 88nominal accounts, split evenly betweenprofit and loss and balance sheet whichcover all the usual business items, plusmemo accounts. It also has the option tomake journal entries.

VAT naturally is catered for and theprogram will provide the figures neces-sary to complete your returns. Thebatch system of data entry is used — thepurchases or sales are put into batchesand the computer checks the batch totalagainst the total individual entries toensure correct entry. Th e data filescreated can be used by the Gemini FinalAccounts program to produce a veryimpressive set o f accounts.

Hestacrest also supplies programs forthe ZX-81 and Spectrum which supplya set o f accounts for either the soletrader or a limited company.

For stock control, there is a widechoice of programs from such firms asGemini, Kemp — which also producesa Stock Ledger — Transform, Hesta-crest and Hilderbay. Using the larger

'Databases is an areawhere people expectthe computer to rule'

Spectrum, Stock Control from Hilder-bay can handle approximately 1,300lines with details of name, stock level,re-order level, type and supplier code,unit value, total value and a text de-scription. There is also the facility toprint-out a list o f all items which arebelow the re-order level or even to printa total stock value.

Databases is an area where peopleexpect the computer to rule. It is able tostore large amounts of data and to man-ipulate it in any way you wish, whetheryou want to control stock, store namesand addresses or to keep track of stocksand shares.

Of those on the market, probably thebest-known are those from CampbellSystems, namely The Fast One for theZX-8I and Masterfile for the SpectrumI6K or 48K. They must be the fastestand most comprehensive available forthe Sinclairs. By using dynamic fields— that is each record and each item ineach record can be of different length —maximum use is made o f the memoryand by writing almost entirely in ma-

chine code you have a very powerfulprogram.

Its one disadvantage, i f it can be soconsidered, is its extreme versatility. Touse it to the full, a passing acquaintancewith computers is a great help, whichmay deter some would-be purchasers.To the business user a pre-packagedstock control or address program mayprove a better choice.

A dedicated mailing list program canprove useful to anyone who wishes tokeep a record of clients or perhaps clubmembers. Address Manager by OCPcan store up to 400 names and addressesfor the purpose and can sort them, i fdesired, into categories. Mail ing l istprograms are also available from Gemi-ni and Hestacrest.

A bane o f an employer's l i fe mustsurely be the calculation of income tax,especially i f more than six weekly-paidworkers are employed. Now, ratherthan doing the job of the Government,you can use your computer. Hilderbay,among others, offers a payroll programwhich it guarantees to be correct; it alsooffers a Statutory Sick Pay program.

The purchase o f a computer couldwell be justified even i f it was intendedonly to be used for one of the foregoingprograms. There are many other areaswhere its calculating ability can be putto good use. The best-known uti l i tybusiness program i s the spreadsheettype o f program. I t can best be de-scribed as a grid o f boxes where eachbox can be identified by its row andcolumn position, with the contents cal-culated by referring to the relevant cal-culation fo r that particular row andcolumn. By altering the criteria for thecalculation it is easy to see the result of awhat-iP situation. O f the Spreadsheettype of programs, VisiCalc for the Spec-trum or ZX-8I from Sinclair are well-known but others are available fromMiCrol, Myrmidon (ZX-81) and Work-force (Spectrum).

Critical Path Analysis from Hilder-bay for both the ZX-8I and Spectrumallows the user to enter a network o fmore than 500 activities, i .e., costs,duration and resources, and the com-puter will find the critical path.

Optimax from Hilderbay for the ZX-81 i s a linear optimisation programwhere up to 75 variables/constraints areentered and the computer finds theoptimum. Fo r example, i f a farmerwants to optimise cattle feed, by enter-ing the nutrient value of foodstuffs andthe cost, the computer wil l determinethe most cost-effective mix.

I f your business is such that all timespent is charged to your clients, as is the

SINCLAIR USER Annu l P.0•1

case ,o . i th a cc ou nt an ts , advertising

agents and the l ike, Ti me Ledgershould prove useful. It can handle up to17 employees and 200 clients and isavailable from Hilderbay for the ZX-8 I

Should you need labels printed, Hil-derbay can supply a program for theSpectrum 48K to print them. The label:an have the date and nine calculablefields o f information and a range o fsizes. I f necessary, the company sup-plies the labels.

Budget, also from Hilderbay for theZX-8I, will help the business user keeptrack o f expenses through the year.Comp-U-Share for the ZX-8 I or Spec-trum 48K allows the user to keep trackof various shares and investments andcan be obtained from Software Work-shop.

Having produced y o u r fi gures,Graph Plot by Gemini will do that, bymeans o f pie charts, histograms o rgraphs. Those graphs aid the user in thecomparison o f figures or as a sellingtool. They are available for both theZX-81 and Spectrum.

One o f the most frequent uses o f acomputer after databases must surely beword processing. With the addition of afull-size keyboard a Sinclair computercan become a very effective word pro-cessor.

Of the programs available, Taswordby Tasman Software for the ZX-8I andTasword Two for the Spectrum standout. Tasword T w o offers facilitieswhich would not be out o f place on aWang system. With 64 characters to theline, the ability to justify text and gener-ally to move it around at will — either asblocks, lines or single words — and tobe able to replace or alter words in themiddle of a piece of text make it a verypowerful system.

Technical or specialist programs arean area which show how cost-effective aSinclair machine can be. Similar pro-grams for larger machines cost in theregion o f £500 for the software aloneand yet i n most cases the programrequires the computer to act only as acalculator on a set number of variables.Any one of those programs, therefore,represents a remarkable saving, in thatin a big company each engineer couldhave his own computer and even in asmaller one the time saved would payfor the machine in its first day of use.One such is Beamscan by G A Rookerfor the ZX-8I or Spectrum, of which afull review is given elsewhere in thissection.

It is well-known that a moving dis-play i n a shop window wi l l attractcustomers. W H Smith puts i t to good


use when it started selling the Spectrumin its stores by using the Spectrum tosell itself. The most recent programaimed at the display market is Dian byCampbell Systems. Using a range o fbuilt-in type styles, colour commandsand scrolling techniques with a built-intimer, a display can be built and madeto alternate displays i n a set timedsequence.

What happens to software wi l l de-pend on the advances i n hardware.Most o f the Spectrum business pro-grams are being updated to take advan-tage of the Microdrive, even though itsreliability has yet to be proved. Thenew Interface Two with ROM cartridgeslot will also add a new edge.

Perhaps the most important additionsto the range of add-ons are the Micronet800 adaptor and the RS232 interfacewhich can be connected easily to amodem. The possibility of, say, two

'The ZX-81 also hasits place in business

in the future'

computers which cost less than DOOcommunicating wi th each other any-where in the world where there is atelephone offers untold possibilities.

The ZX-81 also has its place in busi-ness in the future. Fitted with suitablesensors i t must be the cheapest way onthe market to control equipment, fromfactory machines to a programmableoffice burglar alarm.

Software continues to improve butthe problem is one o f communication.Ten years ago businessmen werebuying £10,000 computers which coulddo less than a ZX-81 today. Today thesame businessmen still spend £10,000

on computers when fo r £5,000 theycould have a complete word processing)accounting package, including the priceof the printer. For software writers it isunfortunately true that business soft-ware is not profitable on anything butthe smallest scale. Unti l businessmenrealise that high prices and high-press-ure salesmanship do not necessarilymean high quality, business use onSinclair machines w i l l remain l i ttlemore than a sideline.

USEFUL ADDRESSES

Blandfold Ltd. Rydings, Gallows Green,Alton, Stoke on Trent.Campbell Systems. 15 Rous Road, Buckhurst Hill, Essex I G9 68L. Tel : 01-5040589.Gemini Mar keti ng Ltd, 1 8 a LittleharnRoad, Exmouth, Devon EX8 20G. Tel :0395-265165/ 265832.Hestacrest Ltd, P O Box 1 9 , LeightonBuzzard, Beds LU7 COG. Tel: 0 5 2 523785,Hilderbay Ltd, 8 - 1 0 Parkway, RegentsPark, London NW1 7 AA. Tel : 0 1 - 4 8 51059,Kemp Ltd, 43 Muswell Hill, London N103PN Te l : 01-444 5499,MiCrol. Freepost, 3 8 Burleigh Street.Cambridge CE11 16R.Myrmidon Software. P O Box 2 , Tad-worth. Surrey KT20Oxford Computer Publishing, PO Box 99.OxfordG A Rooker, 2 0 Vaughan Avenue, Lon-don NW4.Sinclair Research Ltd. Stanhope Road.Camberley, Surrey GU15 3PSThe Software Workshop, Yew Tree, Sel--bourne. Hampshire GU34 3JP.Tasman Software, 17 Hartley Crescent.Leeds LS6 2LL.Transform Ltd. 4 1 Keats House, Por -chestet Mead, Beckenham. Kent. Tel :01-658 6350.Work Force, 1 4 0 Wilsden Avenue, Lu-ton, Beds_

15

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18

Eric Deeson considers uses in the school

MANY YEARS AGO, in the

1970s, the use o f computersin the home was an oddity.

Now something l ike five percent o fBritish families have computers amongtheir prize possessions. That is higherthan anywhere else in the world andSinclair Research must take a great dealof the credit.

In the 1970s the use of computers inschools was also an oddity. Now almostevery British school has one or moreamong its resources for learning. Thatis higher than anywhere else i n theworld, too, and again Sinclair must takea great deal of the credit.

In the former case, Sinclair credit isdue to the fact that the machines headthe list of sales to homes. That is not thecase in schools, where teachers' wisheshave so often differed from the ideas ofcentral Government and local advisers.Credit, however, must still go to Sin-clair, in that its activities increased com-puter awareness i n the country i ngeneral and that increased awareness ledto the decisions to spend money widelyon educational computing.

It i s difficult t o employ statisticsalone. It is certainly clear that the num-bers of schools offering computer activi-ties, and the numbers of candidates inassociated public examinations, have ri-sen at the same explosive rate as generalsales o f micros for less than the £500mark. Data from other countries is diffi-cult to obtain and far less instructive.Even in the U.S., Japan and Australia,all reasonably well along our road,home computing is sti l l for the tinyminority o f middle-class folk and fewschools possess, let alone use, micros inthe classroom.

A primary school head I know, on arecent visit to Japan, asked to see some-thing o f educational computing. H isrequest was received impassively butseveral days later he was taken to acentral Tokyo school. It was a pleasantplace, with all the signs of great expen-diture, and i t had a "computer room".That room contained 12 posh micros,all new, and a pile of boxes hidden in acorner. N o children, n o teacher i ncharge. Was it a put-up job?

How do ZX micros compare to othersin educational contexts? First, I shouldnote what the others are. There are twocomputers claimed by their manufactur-er as th e on ly machines designedspecifically for education. It is certainlythe case that very few, i f any, homeshave them. The manufacturer is Re-search Machines Ltd of Oxford and themicros are the five-year-old 380-Z andits one-year-old sibling, the 480-Z Link.Both are massive and costly. They willprobably always suffer from inadequatesoftware support because the numbersin use are so small compared to those ofmicros which are also marketed to thegeneral public.

The 380-Z and 480-Z are certainlypleasant machines but their size and

'Perhaps no localauthority knows the

facilities in itsschools'

cost and lack of support mean they willnever take computing to the masses o fpupils in a school. Al l the same, somelocal education authorities continue torestrict schools to RML machines forvarious and, i n my view, inadequatereasons. I fear that in the areas o f thecountry concerned, pupils and teacherswill not progress happily towards com-puter confidence.

The Acorn BBC micro is growingrapidly in importance as a school ma-chine, just as it is taking a good share ofthe richer home market. Although thereare too many versions for comfort —different models, operating systems andBasics — it has much more potential foreducation than the R ML competitors.It is cheaper and much easier to movearound and there is an impressive vol-ume o f reasonably good educationalsoftware available for it. Even so, I amless than happy at the implications inAcorn advertising that 70 percent o fmicros in schools are BBCs.

There are other reasonably populareducational machines — popular but inan overall small minority. They includethe Apple — especially in Scotland —the Tandy TRS-80 and its clones, andthe Pet. The Commodore 64 has madesurprisingly little impact on schools asyet and the Vic-20 none, but i t is likelythat the Electron will make inroads indue course.

Having made a few vague statementsabout the popularity of different microsin the educational scene, I wish I couldbe less vague. There was a fl urry o fsmall and large surveys two years ago.That was before the BBC had arrivedand before the ZX-8I had a chance tomake much impact, so the results arealmost meaningless. Since then l i ttlehard information can be added to rein-force impressions.

Data from two o f my recent smallsurveys of school machines perhaps canadd a little. The figures are 35 percentZX-81/Spectrum, 2 9 percent 380-Zi480-Z, 17 percent BBC, 19 percentothers — crude figures from crude sur-veys but perhaps indicating a t leastsomething about BBC advertising.

There are various reasons for the lackof adequate data. The first is that per-haps no local authority knows the com-puting facilities in its schools. That ispartly because computing advisers, i fthey exist, have vast amounts of work todo. Probably even most head teachers,at least at secondary level, could not saywhat equipment is available i n theirschools. I have to think hard what wehave in my department. I f you want toknow, i t is seven Caltexts, two Cro-memcos, two BBCs, two ZX-81s, a 380-Z and a terminal. No-one else knowsthat, apart from the computing teach-ers.

The second reason for the lack of datais the multiplicity o f sources. Manyschools receive at least their first ma-chine through parent-teacher associ-ations, as gifts from local benefactors, oras prizes in competitions. Many othershave bought equipment from science,mathematics or technology budgets. Inall those cases, I am sure, Sinclairs havescored more heavily than other ma-chines, being so inexpensive and sowell-known outside the staff room.

The likelihood of such unconvention-al acquisitions of micros is particularlyhigh in areas where an authority hastold its schools to buy only RML equip-ment. Teachers see a different need forcomputers than many advisers and theyhave often been determined to have aZX, whatever official policy may be.The main reasons for that determina-

SINCLAIR USER Annual 19 R 4

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tion are, of course, price and availabilityof software and other back-up resources.

What then are the needs for comput-ers in schools? I shall not say muchabout that as the uses are fairly obviousand well-documented in magazines andbooks. There is my Spectrum in Educa-tion, for instance. Broadly speaking,computers are used in schools for thesemain purposes:

To give pupils and staff experience inusing them, an aspect o f computerawareness or information technologycourses.

To extend the possible approaches toteaching specific topics compute r -assisted learning we call it in the trade.

To investigate control/data captureapplications.

To provide the means of practicalwork in formal examination courses.

To assist with administrative tasks.For the first three purposes the ZX

machines win hands down. They areinexpensive. You can equip a room ifyou wish with 12 Spectrums in a net-work, plus Microdrives, two ZX print-ers and a better-quality printer for lessthan 13,000. That sum would buy you asystem based on only two 380-Zs or, ifusing BBCs, five or six machines. Passover the permanent network idea andthe ZX way gives you sufficient powerfor every teacher to have good access,even in a large school.

Those teachers would welcome thesecond huge Sinclair advantage, themass of cheap, fairly good learning soft-ware available for home and schoolsuse. Not many of us have the time todevelop many good programs for thepurposes of our colleagues. There isalso in the Sinclair case a wealth ofmagazine articles and books, again sav-ing the individual a vast amount of timeand frustration.

It is only when one reaches the lasttwo educational applications in my listthat the anti-Sinclair case becomes sig-nificant. Yet, even there, we find ZXsin positions of strength around the


country. Many schools base even ad-vanced level programming courses onZX-8 Is and Spectrums and many teach-ers have at least some administrativepackages up and running.

I am preaching to the converted, ofcourse. I f you are reading this publica-tion you will already believe that Sin-clair micros are the greatest. Be aware,then, that not everyone agrees with you,and in the corridors of political powertierce battles will still have to be foughton behalf of Britain's youth.

What does Britain's youth need?Why did I begin by saying a shortprayer of thanksgiving to Sir Clive Sin-clair? In my opinion the pupils in ourschools need and want to be able toacquire a high level of confidence andfamiliarity with computers. Computerswill offer more and more threats tosociety — to privacy, employment, free-dom, peace — and it is essential thatevery citizen knows that the machinesare no more than friendly slaves.

By the end of the decade it is likelythat powerful, fully-portable micros willcost something like £10 and that thepresent problems of inadequate supportwill be on the way out. When that dayarrives I would hope that as manymembers of the world community aspossible will be able to have such amachine and be able to enjoy, welcomeand benefit from its use.

The only way we can approach evenfeebly that state of readiness is to maxi-

mise the use of computers in schools,colleges and homes. They must there-fore be as cheap, portable and powerfulas possible. They must be supported byplenty of software and print resources. Ibelieve that only the Sinclair rangemeets that description.

Although many teachers feel thatway, educational computing remainsmuch too fossilised in the approach ofthe early 1970s. Too many schools havemassive, costly, unsupported machineswith which the word user-friendlinesshas no meaning. Few schools can offermore than one micro per 100 pupils andmore than two teachers able to use theequipment with ease.

The appearance of the BBC machineis helping significantly but ZX-8 Is andSpectrums remain the only sign of sal-vation. One large authority in Britain isgoing the other way. It is introducing anunknown business machine costing£2,000 as the standard. That machinehas no colour nor sound and only blockgraphics. I understand it does not evenhave a manual.

While that kind of approach con-tinues, educational computing will befor only a small minority. There is noway that all pupils will treat micros asfriends — no way will many teacherseven find the machines of use in theirwork. The computing teacher will reignas a high priest over a mystical templeand a small band of unintelligible wor-shippers. That is an abhorrent picture.

Three-and-a-half years ago I foundedthe Educational ZX Users Group with-in MUSE, the British educational com-puting association. EZUG grew out ofall recognition, far beyond my ability tocope. It showed me that thousands ofteachers and parents were convinced ofthe value of the Sinclair approach tocomputing in schools. Now EZUG isre-absorbed within MUSE, its functionas a banner-waver fulfilled.

All the same, though the banner-waving is over, the battle for recogni-tion won, the war is still a long wayfrom a conclusion. I hope that theconclusion will be computers accessibleand valuable to all in our schools but

'Educational computing remains fossilised inthe approach of the early 1970s. Too manyschools have massive unsupported machineswith which user-friendliness has no meaning'

there are many high priests in the corri-dors of power who continue to fight forcomputing for the few.• Alas, I fear that even if the war goesour way, there still will be no time torest. There are few countries in theworld where the war has even beendeclared. Sinclair is leading Britain to-wards Computer-Assisted Freedom;Britain will then have to do some lead-ing, to give all human beings a bravenew world rather than a big brothersociety.Erie Dawn, who teaches in Btrmsigham, organtsedthe world-unde Edsreational ZX Users' Group and ashonorary editor of the MUSE magazine, Comput-crs in Schools.

19

John Gilbert reviews more complex games

Arcades broughtinto the home

LMOST every major ty pe o farcade game has been simulatedon Sinc lair computers. There

are also new games whic h have anarcade format but have evolved on amicrocomputer. T he Spectrum is anideal machine on which to play arcadegames. T he quality o f them has im-proved substantially since the launch ofthe machine. Some o f the fi rst arcadegames to be produced for the Spectrumwere versions o f Space Invaders, thegame which started the arcade craze.

Spectral Invaders was the first tobe announced by Bug-Byte, which wasalready renowned for i t s arcade andadventure games on the ZX-8 I. So far itis the game which most closely resem-bles the or iginal arcade version. Al-though it is slow it is diffi cult to scorepoints, as you can fi re only one laserblast at a time.

Another invaders game, Space In-truders, was launched a t about thesame time as Spectral Invaders. T hegame is much faster and is recommen-ded for those who lik e to keep theirfingers on the fi re button and amass abig score. The only criticism is that thealiens and mothercraft are very smalland the mothership is blue on a blackbackground and so is very diffi cult tohit. Apar t from that Space Intrudersfrom Quicksilva is good value at £5.95. Namtir Raiders, for the ZX-8I, is aspace invaders game with a differencefrom Artic Computing. The player stillhas to face the hordes o f aliens whichcome down the screen but the laser basecan be moved up and down as well asleft and right.

The player has five laser bases duringthe game and they can take only fi vehits from alien bombs. There are threelevels of difficulty—easy to impossible.The game, costing £3.95, is addictiveand the graphics are neither awkward indesign nor jerky in movement.

The game which is gaining popular-ity with 48K Spectrum owners is T imeGate, f r om Quicksilva. T he authorsclaim that it is the ultimate in 3D arcadespace action. The game is loaded in twoparts, the first being a lengthy instruc-tion manual. After the manual has fin-ished you can load the game. The object

is to destroy a race o f aliens called theSquarm w ho are t r y ing t o coloniseEarth. The enemy fighters are also seenin 3D and so are the planets on whichthe player can land to refuel and repairthe ship. I t is by far the best arcadeaction game so far for the Spectrum andcosts only 0.95.

Asteroids is also becoming popularon Sinclair machines. One o f the fi rstcompanies to launch a version for theZX-81 was Quicksilva. I t was a goodversion on such a small machine and isstill proving popular.

Quicksilva has als o introduced aSpectrum v er s ion c a l l e d M e t e o r

Storm. I t has the added attraction o fspeech before play. It is diffi cult to hearthe words but we are informed by theauthors that it says "Meteor AlertMeteor Aler t . " . Meteor Storm is anovel version o f Asteroids and costs0.95.

Sinclair Research has a good game ofasteroids, called Planetoids , in its newSpectrum Software library. The aster-oids are in 3D and much careful designwork on both the asteroids and theplayer's ship seems to have gone intothe game. Planetoids costs 0.95.

Artie Computing seems t o be theonly company to have produced a ver-sion o f Galaxians for the ZX-81„ Z X-Galaxians looks like Space Invadersbut the invaders are 'T-shaped and are

supposed to be inter-galactic birds. Thebirds swoop from formation and bombthe player's laser base. ZX-Galaxian isslow in action but can s t ill be a veryaddictive game. It costs L4.95.

Defender is still a much-sought-aftergame in the arcades and Artic Comput-ing took advantage o f that ear ly b yproducing a version for the ZX-81. Thegraphics are not particularly interestingand the spaceship which the player fliesacross the landscape is made up o f aseries of blocks which look only slightlylike a ship.

Despite those criticisms, the originalidea behind the game is s till there andthe Artic version can be exciting, as yousee the enemy ships rushing at you fromthe other side of the screen.

With the arrival o f the Spectrum,many manufacturers found an interestin the arcade game Sc r amble. T h ebest and fastest version so far is fromMikro-Gen. In the game you have to gothrough caves which become smallerand smaller as it progresses.

The game becomes progressivelymore diffi cult and can be run in slow,normal and fast modes. I t costs £3.95.

Silversoft has a Scramble-type gamecalled Ground Attack. It works on thesame principles as the Mikro-Gen gamebut is much slower. There is a good dealof blank screen between game roundsand the average waiting time betweenrounds is 15 seconds. Ground Attackcosts £5.95.

The range o f arcade-type games onSinclair machines is always increasing.Manufacturers seem to feel safe in pro-ducing standard arcade games such asSpace invaders and Scramble. Thosegames, especially for the Spectrum, arebecoming more imaginative and thegraphics and sound more impressive.

Manufacturers have t o be carefulabout copying ideas from other gamesbut with the imagination of some of thefirms in the Sinclair market, childrenand many adults w i l l be kept happywith arcade-type games on the ZX-81and Spectrum for a long time.

Space Invaders games have now beenovertaken by Pacman in popularity.

Bug-Byte, 9 8 1 0 0 The Albany. Old Hall Street,Liverpool L3 9EP

Ouicksilva, 92 Northam Road, Southampton SO2OP8

Artie Compting, 396 James Reckitt Avenue, HuilNorth Humberside

Sinclair Research, Stanhope Road, Camberley.Surrey GLI15 3PS-

M i k r o-G on, 2 4 A ga r C re sc en t, Bracknel l, Berkshire

RG12 213k.

Silversoh. 20 Orange Street. London WC2H 7E0

20 S I N C L A I R USER Annuai 1984

•

VAMPIRE VILLAGEIn a ruined castle near the village of Vladsdorflurks a vampire who roams by night.As mayor you must organise volunteers to save

SPACE ISLAND Reports J m e distortion around a P'•distnt planet lead you into the stran n t

civilisation that although lodead, now threatens the pres

This is a REAL-TIME graadventure and every gdifferent from the one befor

•

For the

i r- -1=Imi r- 48k

SpectrumAll Super Value at Rec. Price £6.95

•

the villagers.This is a REAL-TIME graphicadventure and every game isdifferent from the one before.

•

CITYA unique REAL-TIME better-than-a-board game for 1-4players that combines simplicity of use with complexityof form as the city you build takes on a life of its own.A flinctiorting economic model for you to play' while•

the Spectrum keeps track of thetime, the money, the propertiesand the people.

gdoi Agit*

TERMI NAL SOFTWARE28 CHURCH LANE, PRESTWICH, MANCHESTER M25 SAL

TEL:061-773 9313

Applications forthe Sinclair athome and the officeWhy not stop playing games and do some-thing interesting with your computer? JohnGilbert assesses the software

B O T H SINCLAIR machines canbe used for storing data o f anykind, such as names and address-

es, telephone numbers and even a never-changing record o f appointments.The ZX-8I needs the 16K R AM packfor any k ind o f data storage and bothinformation and program have t o beSAVEd together. T hat operation cantake up to six minutes and is not veryreliable.

The Business and Household cas-sette was one of the first packages avail-able from Sinc lair for the ZX-81. I tcontains three programs. One will keepa record o f names and addresses, thenext will keep a diary of events and thefinal program will handle all your finan-cial transactions.

The fi rst two programs worked wellbut the Ba n k Ac c ount program onside two took six minutes to load andSAVEing the program back on to tapewith the data proved very diffi cult.

The Business and Household cassettemay not be very reliable but it is goodvalue at £3.95.

One o f the best data managementsystems available for the ZX-81 is TheFast One, from Campbell Systems. I tallows the user to set up fi les of infor-mation i n any way which suits h im.The program w il l sort and search forspecific bits of data and i f numbers arebeing used i t is possible to total them.The program is a step forward for theZX-81 and is very flexible. I t w i l l doany kind of fi ling job, given the limita-tions o f the machine. T he Fast Onecosts £15 and has a comprehensive man-ual.

Spreadsheet programs are a n easyway to store numerical data in a formatin which i t can be used for calcula-tions. The spreadsheet is a matr ix , ortable, on the screen and any box, or cell,in the table can be addressed by usingthe letters and numbers which run hori-zontally and vertically at the sides of the

sheet. This type of program can be usedto plan the family budget and calculateautomatically running totals o f familyexpenditure. That is only one of themany applications for which it can beused in the home.

MiCROL produces a spreadsheetprogram called Matrix Planner. It iseasy to use and has a spreadsheet o feight rows by 30 columns. That con-figuration can be changed by the userthrough t h e program variables. Ap -proximately 300 cells can be created inthe matrix before all the 16K o f mem-ory is used.

Sinclair Research markets two pro-grams s imilar to the Matr ix Planner.Vu-Cale is a program which uses thespreadsheet. It has limitless possibilitiesand can be used for financial modelling,keeping track of bank accounts and evensetting-up scientific experiments whichrely on number-crunching for their out-come.

The second is Vu-fi le. I t is like Vu-Cale but the user can only store infor-mation and not perform calculations on

'There are programsfor data storage onthe Spectrum butmost of them can

be used only on the48K version'

data. Both programs are available forthe ZX-8I and Spectrum. Z X- 8I ver-sions cost (3.95 and Spectrum versionsL8.95.

The arrival o f the Spectrum set soft-ware houses the task of writing pro-grams which can use data files separatefrom the programs. It has opened theway to storing large amounts of data oncassette and, with the arrival of the


Microdrive on fl oppy tape. There areseveral good programs for data storageon the Spectrum but most of them canbe used only on the 48K version.

The Database f r om MI C R O L isone such program. The files can be splitinto documents. Those documents areuseful in splitting-up topics within themachine. You can give each document aheading, such as tax, income or budget,and you can have several o f them inmemory at one time.

Documents are split further into re-cords, with one record corresponding toeach datum. W i t h that system i t i spossible to do your tax and budgets atthe same time, without having to loadthe computer twice w ith information.The program can store up to 999 recordlines in memory. T he Database costs0.95 and is complete with handbook.

The. Mas t e r fi le p r og r am f r o mCampbell Systems is the most compre-hensive of the databases available. I t is

'Most dataprocessing programscan already deal with

more informationthan the ordinary

user needs'the successor to The Fast One for theZX-8I and provides fast access to largeamounts o f information. The user canalso model the program to meet specificrequirements. Data can be sorted andsearched and reports can be compiledusing the system. ,Masterfile costs £15for the 48K version and £12 for I6K.

The spreadsheets whic h proved sopopular with the ZX-81 are starting tocreep on to the Spectrum market Thebest, so far, are from MiCROL and Mi-crosphere. Both are remarkably similar.The MiCROL version costs 0 .95 andprovides the basic calculating power ofmost spreadsheet programs. I t is easy touse and can help the business or homeMCI with complicated calculations.

Omnicalc is the spreadsheet f r omMicrosphere. I t is ideal for someonewho has jus t found the spreadsheetconcept but i t is also a very powerfultool for anyone who has used one pre-viously. T he program seems to workfaster than the M iC R O L spreadsheetand information can be accessed almostimmediately.

The screen format is easily under-standable and very clear for the fi rst-

SINCLAIR USER Annual l984

time user. The program contains a helpoption which lists the commands avail-able through the spreadsheet. Omnicalccosts 0 ,95. I t is complete with a usermanual.

All-Sor t is an interesting utility pro-gram for the 48K Spectrum. It enables auser to sort data which has been set upwithin a home-built program. The datais stored init ially in an array and All-Sort can sort up to four of them at once.It can be obtained from Alan Firminger.The program is useful and very fast butat £18 exclusive of VAT it is expensive.

L i s & le i s a program whic h doesexactly what i t s name suggests. T h eprogram allows a user to store lists o fdata, such as names and addresses, andto access that information very quickly.Data is entered in blocks which can beup to eight lines of 26 characters long.An extra line, called the info line, can beused to index information but that isnot printed-out when the printer is usedto list the information.

Listfi le is available for the 16K and48K Spectrum and can be obtainedfrom G and I Bobker. I t costs DO andhas full documentation.

Now that the Spectrum has arrived,software manufacturers are beginningto think about software uses other thangames on Sinc lair machines. The dataprocessing programs c o u ld h a n d lemany tasks which are centred on thehome. Databases, such as the one fromMiCROI,, are useful for storing textualinformation, such as a lis t o f favouriterecords or even knitting patterns.

The Microdrive can expand the dataprocessing capabilities of the Spectrum.Information c an b e accessed mo r equickly and as a result bigger programscan be stored in memory and data canbe fed in bit by bit.

The capabilities o f the Spectrumcan be extended in this way but soonwe w i l l have to decide whether i t isnecessary. Mos t data processing pro-grams can already deal with more infor-mation than the ordinary user needs. I tmay be proved that that type o f appli-cation for the Microdrive is a waste o ftime.

Sinclair Research, Camberley, Surrey GUI b3BRMiCROL, 3 1 Bur leigh Street, Cambr i dgeCBI 1BR.Campbell Systems, 1 5 Rous Road, Buckhurst Hill, Essex 1G9 6I31.Microsphere Computer Services Ltd, 7 2Rosebery Road, London NI O 2LA.Alan Firminger, 1 7 1 Her ne Hi l l , LondonSE 24 9L RG and J Bobker. 29 Chadderton Drive, Uns-worth, Bury, Lancs.

23

24

New and varied life-forms now inhabit thePacman maze. John Gilbert investigates.

Eng the PacpACMAN is part of what the

video historians like to call thearcade maze craze. The game is

set in a maze where a hungry littleround creature eats dots and power pillsscattered through the corridors. Themonsters are ghosts which hunt thelittle man and will eat him if he is notagile enough to escape.

If, however, the Pacman eats a powerpill it can chase and eat the ghosts. Theoriginal game was introduced to thehome computer market b y Atari,primarily on its VCS video system andthen on the 400 and 800 computers.

The first versions for other computers,variously called Puckman, Gobblemanand Scoffer, arrived shortly afterwardsand since then new versions have beenreleased almost every month.

Not surprisingly, the ZX-8I did notescape the craze. T h e authors o fZuckman, from D X Software, claimedthat it as the first version of Pacman for

the ZX-81. The game runs in 16K andis written in machine code, which givesthe scrolling routines and Pacman asmooth movement. That is somethingunusual on the ZX-8I, as most gamesflicker slightly.

The game adheres as closely as possibleto the original and the limited graphics ofthe ZX-81 do not matter much. One snagwith playing the game on the ZX-81 isthe membrane keyboard. Moving aPacman round the screen using it can bedifficult but not impossible.

At the beginning of Zuckman theghosts speed on their victim and if youpanic trying to find the keys and do notpress them properly you are liable to losea Pacman or crash the machine. Once youhave a fair idea of the game, however, it issurprising how quickly you can move thePacman around.

Zuckman is available for £5.95 on theI 6K ZX-8 I and Spectrum. SuperGlooper is a version or Pacman, also forthe 16K ZX-81, which is retailed bySinclair Research. Glooper's task isslightly different from normal. Instead ofgorging himself with power pills he hasto paint the maze. Obviously the ghostswill not tolerate Glooper's antics —perhaps they do not like the smell of

paint. The ghosts will try to kill Glooperas usual but if he can get round the mazeand paint all the walls you have won.

The game is very amusing and is wellworth £4.95. The program will load inless than two minutes, so you will nothave to wait six minutes to play the game.

The launch of the Spectrum providedsoftware houses with an excuse to try toproduce the perfect Pacman whichsimulated the Atari version as closely aspossible but Atari guards its rights overproducts jealously and investigated theproducts of several firms in the ZXindustry.

The Abbex Spookyman game is themost famous of the Sptctrum versions. Italso looks most like the original. Mostgames, until then, included only dotsand power pills in the mazes. Abbexincluded dots, power blobs, diamonds,hearts, clubs, mean-looking ghosts and acute little Pacman which looks like adiamond turned on its side.

The keyboard is divided into threesections with left control on the left, righton the right, and up and down in thecentre. The controls are very difficult tomaster but, once you have done so,usually with the aid of both hands, youwill be surprised at the agility you canattain.

At times the game is almost impossiblyfast but Abbex estimates that the highestscore possible after every screen has beencleared is 22,400. If you manage to reach10,000 points you will receive a bonuslife. We managed to go that far only once.

Spookvman can be played by one ortwo players. If two play they take turns tocontrol the Pacman. Their individualscores and the highest score are includedat the top of the screen.

There are two unusual features inSpookyman. The first is that you can re-set the high score at any time betweengames; the second is that you can use ajoystick. The game is compatible withthe Kempston joystick and once you haveseen it in action it is almost a necessity.Spookyman is available from Abbex andcosts f4.95_

GuIpman is another variation onthe Pacman theme. T h e roundPacman is replaced by a little man


• = • • •M IEEM L .

St

isC.Drtoal

inre-ena

ithlyety.nd

onndIan

4a1 1984

running round the maze and the ghostsbecome frowning faces which smileonly when they have caught Guipman•

The game is very complex and youcan switch to any of 15 mazes in whichto play. It is also possible to change thetempo. A t tempo one the speed isbearable but a t tempo 10 l i fe is notworth living.

The little man can fight back slightlymore easily than in other games as heapproaches wi th a fully-loaded lasergun. If the ghosts get too close you canblast them away but only until yourenergy runs out. It seems as if the spaceage i s over-running everyth ing.Guipman is available from CampbellSystems and costs 15.95.

Hungry Horace , from SinclairResearch, has developed a reputation as afun game; in fact Horace is almost alegend. The game is a great improvementon the original and remained at the topof the software top ten for some time.

Horace is a large purple blob whichhas sprouted arms and legs. He wandersround the maze which looks like a park,eating everything in his path and tryingto avoid the guards who act like ghostsand try to capture him. He can scare awaythe guards b y using the alarm bellsituated somewhere in the maze.

If Horace reaches the exit of one of themazes he can enter the next maze andcontinue to the next exit. The mazesbecome more d i ffi cu l t a s Horaceproceeds further in his adventure and wemanaged to reach only the third maze.With a large amount of skill, however, itshould be possible to go further.

Hungry Horace , f o r th e 1 6 KSpectrum, i s available from SinclairResearch and costs £5.95.

Although the arcade industry in theStates, and now in Britain, is declining itis good to see that games concepts likePacman are being transferred to micros.

Some o f the Sinclair versions o fPacman seem as good as, i f not betterthan, the original Atari version. Gamessuch as Hungry Horace are setting-up aninteresting mutation i n the Pacmanconcept. They also seem more interest-ing than the original version because theyhave added to the idea of Pacman. So faras the consumer is concerned i t is to behoped that concepts such as Pacman willnot be destroyed within the industry.DJL Sof tware, 9 Tweed Close, Swindon,VVilts. 5N2 3PUSinclair Research. Stanhope Road,Camberley, Surrey. GU15 3PS_Abbex Electronics Ltd. 20 Ashley Court,Great North Way, London, NW5Campbell Systems. I Dept. SW, 15 PousRoad, Buckhurst HI , Essex, 1G9 6BL

SINCLAIR USER Ant wal 198425

Backgammon has long been a popular game which requires a mixtureof luck and skill. John Lambert reports on three versions

Ancient game has variedsuccess on the SpectrumBACKGAMMON is an ancient

game involving much more skillthan draughts, ye t dependent

more on luck than chess. It is as old, orpossibly older than any o f them. Theancient civilisations of China, India andGreece al l offer possible birthplaces.There are three versions of the game forthe Spectrum by Psion, 16K; HewsonConsultants, I6K; and C P Software,48K; all priced at £5.95.

Each cassette has instructions fo rthose new to the game. Those writtenfor C P are good, clear and detailed.Backgammon is a complex game andthe notes make play easy for a completebeginner. The Psion instructions areequally useful but those provided byHewson are not nearly as well pu ttogether and might be confusing for thenovice.

When playing Backgammon, the vi-sual impact o f the board and layout o fthe 'men' is vitally important — youneed to be able to assess your positionand your opponent's at a glance, so thegraphics are a prime consideration.

On loading, Hewson offers a choiceof single game, points series, gamblingseries or a demonstration game. Thelatter is very helpful for the newcomerand compensates a l i ttle fo r the de-ficiency in written instructions. Thereis also a choice of static levels and youcan choose who starts the game, al-though, strictly speaking, that is againstthe rules.

The board is swiftly presented butunfortunately it is not easy to see, eitherin colour or black and white. The 'men'do not stand out from the board and thecomputer moves are made much tooquickly for the experienced player tofollow, let alone the novice. A record ofthe moves appears on screen below thetable. The Hewson graphics are simpleand not very effective compared to theothers.

Load the C P version and you arepresented wi th brief instructions fo rplay, which neither o f the others pro-vides on-screen, but there is no choiceof skill level. The graphics are muchbetter than those o f Hewson, though

the board is drawn very slowly, thatpart of the program being in Basic. Thedefinition i s good, making the meneasily visible in colour, and only a littleless so in black and white, but since thepoints are not coloured alternately asthey should be i t is often difficult tocalculate your moves. In this programthe chosen pieces flash before a move ismade so that i t is easy to follow and arecord is kept below of the moves, but it

'The CP graphics are much better than thoseof Hewson, though the board is drawn veryslowly, that part being in Basic. The defin-ition is good, making the men easily visible'

is SLOW and your moves have to beentered singly, which can be frustratingwhen a double is thrown.

In its normal fashion, Psion presentsa screen display for you to look at whilethe game is loading, even though thescreen takes almost as long as the gameto load. Incidentally that was a blackmark for Psion; whoever drew its screenshould have realised that opposite faceson a dice add to seven rather thanadjacent ones. That criticism, however,should not detract from the spectacularnature of board display. You select fromfour skill levels, with a demonstrationgame available, and then are given theopportunity to input your own dicethrows. It is the only one o f the threewhich allows this, a feature which othergames programmers would be wise tocopy since your faith in the randomnessof the RND generator will be shaken bythe dice thrown in all the programs.

The board is drawn quickly with thepoints coloured alternately in black andwhite and the pieces, large enough tosee easily, four character squares, in redand cyan. The definition is not lostwhen using a black and white television.The dice 'roll' in 3D up the screen andthe pieces move across the board frompoint to point, making i t simple tofollow the course of the game. On the

points with more than five men, thepieces appear to stand on their edges tomake space, whereas the other twogames resort to using numbers in thatsituation. When blots are hit, they trav-el gracefully to the bar, where a maxi-mum of two men of any one player areshown at a time.

In the middle of the bar is the dou-bling cube, which moves from player toplayer in use. Hewson is the only other

game to offer doubles but only in itsgambling series.

Moves can be changed after theyhave been made by use of the DELETEkey, the men re-tracing their stepsacross the screen. EDIT elicits suggestedmoves t o he lp th e novice playerthroughout the game. The graphic dis-play is well-designed and effective.

All the games use the conventionalrules o f play, as published by Hoyle,but for scoring C P has no doublingoption, an integral part o f the moderngame. Hewson uses its own method ofcalculating points instead of the accept-ed one. Only Psion scores correctly.

Hewson plays erratically, sometimesbeing very conservative and at othertimes taking wild risks. Moreover, bymoving about frequently within its owninner table i t i s unable to take fu l ladvantage of the dice. When playing aback game i t does not persevere longenough and on one occasion when oneof its men was on the bar and most of itsopponent pieces had been borne o f fleaving a blot on the three, Hewsonthrew five/three and came i n on thefive, thus losing a gammon. Apart fromthat instance i t usually 'hits' at almostevery opportunity and so i t can betrapped by a skilful opponent. On thewhole the level o f play, even a t i ts

26 SINCLAIR USER Annual 1984

highest, is moderate and does not pro-vide a stimulating challenge to an exper-ienced player.

It is interesting to note that M Male,the author, also wrote the excellent airtraffic control simulation, Heathrow,for Hewson.

C P is another fanatical taker, butrarely takes the conventional precautionof building houses in its inner table. Onthe rest of the board its moves aregenerally conservative but its defeats ofHewson, as indeed when Hewson beatit, depended on some very lucky dicethrows towards the end of the game.The two programs are well matched,their skill levels being about the sameand their strategies very similar.

Psion plays a much more sensiblegame and provides more of a challenge.It makes better and more frequent useof the standard openings and its strategythroughout the game is more consistent.It protects its inner table and leaves fewunnecessary blots but once again whenplaying a back game it tends to lackconviction and runs for home too soon.

To test the abilities of the games a'tournament' was arranged. Each pro-gram played five games against each ofthe others. The results, shown in thetable, were surprisingly even.

It was expected, on the basis of play-ing the game individually, that the re-

Psion V.Hewson

1 2 3B

4W

5

WPsion wins 5/3

Hewson v.CP

CP wins 8/1

CP v.Psion W G

G Draw

W = Win G Gammon B — Backgammon


RESULTS

suit would be Psion first, Hewson andthen C P. None of those programs,however, can assess the play of its oppo-nent, which is why they fail to takeadvantage of each other's faults. Humanplayers would assess and eventually pre-dict their opponent's moves, frustrating

'Results dependedoften merely on the

luck of the dice'a back game by refusing to hit blots, oravoiding blots left as obvious traps.

Since the programs cannot do that,the Psion game, for example, fails torealise that its opponents play consis-tently badly and cannot capitalise onthat as a human player does. For the

same reasons, Hewson and C P opposedeach other three times with identicalstrategies and neither was able to realisethat and alter its play accordingly. Theresults therefore depended often merelyon the luck of the dice.

The Psion game is programmed en-tirely in machine code and so uses thecomparatively small space available on aI6K machine efficently, even using thespare space in the printer buffer for thetable of the positions of the men on theboards. Now the Microdrive is availableit may be a problem to fit it in. On theother hand Hewson and C P are writtenpredominantly in Basic, Hewson about70 percent and C P nearly 90 percent;that makes them somewhat cumber-some and would, particularly in the caseof C P, welcome the use of a goodcompiler,

27

Tower of Babelhits Sinclair

As more users become accustomed to Sinclair Basicand its limitations they have turned to other languages

to help solve particular problems. John Gilbert investigatesthe growing demand for new ways of conversing withyour machine, such as Forth, Pascal, Logo and Lisp.

BASIC, as used on the ZX-8I and

Spectrum, is a high-level lan-guage. That means that it is easi-

ly understood by human operators butthat the computer has to translate anyentry made by a user into the codewhich it understands.

Basic was designed to help peoplebecome accustomed to a computer andwas not written to perform any particu-lar task. That is the problem with itwhen compared to other languages.Languages such as Forth and Fortranwere written to perform specific tasks.

Forth has already been implementedon the ZX-81 and some versions areavailable for the 48K Spectrum. Thelanguage was designed originally forengineers who needed to process formu-lae. It runs at many times the speed ofBasic and, with graphics added to thelist of commands available, you can playa good game of space invaders by usingit.

The most interesting aspect of Forthis that you can define your own com-mands using words which already existas part o f the standard system. Adictionary of those words usually isaccessible on the system using a listcommand. For instance, if you want tofind the square of a number you woulduse the standard word DUP. I f youwant to find the square of a numbersquared again you could define yourown word, for instance DUPD, by de-fining it as DUP*DUP. All that seemsvery complicated i f you are used toBasic.

Some languages require even morediscipline on the part of the program-mer.

Pascal, for instance, is a languagewhich requires the programmer to de-fine all variables and functions usedthroughout the program in the first

section of the code. A program writtenin Pascal must then be structured as aseries of routines, each routine beingrelatively independent of the others.

The language is slightly more diffi-cult to use than Basic as it forces the

P101 SO much BASIC as EARTHY. "

programmer to think about how thecode is to be put into the computer,which operations are to be performedfirst, and where routines are to beplaced in a program, instead of decidingwhat code you need for a specific job.

Children and schoolteachers are be-coming interested in a language calledLogo, which has been iMported fromthe U.S. Its inventor is Seymour Papertand embodied in it are several contro-versial concepts which many education-alists are beginning to question.

The emphasis of the language lays

with teaching children about mathemat-ics through graphics shapes on thescreen and through the use of a robot,called a turtle, which can be controlledfrom a computer. The robot can be usedto draw shapes on the floor and putsinto practice the concept of learning byexperience.

Educationalists in Britain are scepti-cal about using turtles in that way. Thereason is that learning in British schoolshas been, and still is, by the repetitiverote learning method.

Some schools are experimenting withturtles but the lessons taught usingthem have been structured so that chil-dren are still learning by rote and not byexperiment or experience.

At present, Sinclair Research is de-signing a version of Logo to work on theSpectrum. Edinburgh University is alsoworking hard to produce a floor turtlefor the machine. The language will besupplied free to schools which choosethe Spectrum under the GovernmentMicrocomputers in Schools scheme.

The artificial intelligence languageLisp has already been released for theSpectrum by Serious Software. Lisp isused for list processing and programscan be written which will act like intelli-gent databases.

Serious Software has provided a data-base written using the Lisp package. Itincludes the names of a family groupwith relations which they form to eachother. Using the program you can dis-cover which members of the familyhave children, which have brothers, andwhether those brothers are married.The database seems intelligent becauseyou can ask i t questions which arelimited only by your imagination.

Normal databases would allow infor-mation to be accessed only using suchtechniques as entering a keyword to

28 S I N C L A I R USER Annual 1984

1

find data. You can also use Lisp to writeprograms which will seem to give mean-ingful answers to entries you type intothe computer. The computer will selectan answer depending on the data whichis stored in its memory and how it hasanswered questions similar to the cur-rent one.

Programs which simulate this type ofintelligent computer response havebeen written in Basic. One such pro-gram, Eliza, acts l ike a human psy-chiatrist and many o f the replies i tgenerates seem almost too much likehuman response.

The Eliza program in Basic is amus-ing but with large amounts o f data inmemory the program will respond veryslowly, sometimes taking two minutesto analyse entries. Lisp was devised forthat kind o f work and so i t has theadvantage o f speed over Basic in thisarea.

Most computer languages were de-signed with a purpose. Unfortunately,languages like Basic have been corrupt-ed and are now used for different pur-poses from those which their designershad intended.

Basic was not intended as a commer-cially-used programming language fo rthe design of space invader games. Un-fortunately, programmers can use onlythe langauge available to them and onthe Spectrum that i s either Basic o rmachine code.

Sinclair is now making it possible touse other languages but Basic is still themost popular, not because people like itbetter than other languages but becausevery few people have had the opportu-nity to use any of the others.

Only one small microcomputer hasbeen produced which wi l l run a lan-guage other than Basic, the Jupiter Ace.Sinclair is definitely an innovator in themarket, so perhaps a micro with a newdedicated business language may be thenext step.

FORTHArtic Computing. 3 9 6 James Reckitt Ave-nue, Hull. Nor th Humberside, ( 48K Spec-trumiZX•81).Abersoft. 7 Ma e s Mal l en, B o w Str eet.Dyfed SY24 5BA. (Spectrum 48K),PASCALInterlace, Dept . S U. 4 4 - 4 6 Earls Cour tRoad, London W8 6EJ. (Book wi th Basiccompiler).LOGOSinclair Research. Fr eepost. Camber ley,Surrey GUI S 3BR. (Spectrum — t o be re-leased).LISPSerious Software. 7 Woodside Road, Bick.ley_ Kent BR1 2ES. (Spectrum 48K).


Writing programs i s time-consuming. John Gilbert examines acollection of cassettes which help to make the job much simpler

The easier route fromasic to machine code

THE BEST WAY to learn about

machine code is to use an as-sembler. Machine code consists

of numbers but with an assembler theuser can write code in assembler lan-guav, which looks more like Basic andis easier to understand. The programwill then convert the user's assemblylanguage instructions, called sourcecode, into machine code.

Although the ZX-81 has been aroundfor several years there are only a fewmachine code assemblers available onthe market for i t. The only big com-panies to produce assemblers for themachine are Artic Computing and Bug-

Byte. Both built their reputations withthese assemblers.

The Attic assembler is a two-passprogram. I t w i l l permit fu l l use o flabels, will inspect and modify registersand also allows output to a printer. Thecode to be assembled is put into a REMstatement at the beginning o f the pro-gram and all code can be written instandard Z-80 mnemonics. The assem-bler will also assemble messages whichare to be used in programs into hexade-cimal code. It costs 0.95.

The other best-seller is the Bug-ByteZXAS. The program is similar to thatof Artic but was launched in a blaze of

publicity as being the fi rst machinecode assembler for the ZX-81.

Bug-Byte also wanted to be the com-pany which produced the first assem-bler for the Spectrum but i t was to bedisappointed. Wrangling w i th in th ecompany between its programmers putthe release date further and further backuntil the package became available earlyin 1983.

The program is for the I6K and 48KSpectrum, It is very comprehensive inits options and very easy to use. As wellas assembling user machine code, it hasa full editor facility with which the user


can v iew assembly code, delete andinsert, search for specific strings of textwithin machine code, and lis t a l l thelabels which have been specified by auser in a program within a cross-refer-enced table.

The editor w i l l also reverse 16-bitvalues, such as memory addresses, i f theuser specifies that option. That facilityis useful when dealing w it h a largenumber o f 16-bit addresses in a longprogram. The use o f 16-bit values canbe a problem for beginners, who oftendo not know whether or not to reverse anumber.

The program also has a good cassetteinterface. Both the source code — theuser's — and the object code — assem-bled-code can be fi led on t o cassette.That means that source code can besaved and re-edited when the user needsit. The saved source code could also beuseful i f the programmer wanted t oupgrade a program.

Unfortunately the manual, or lack o fit, provides po in ts agains t Aspec t.Instructions are wr itten on a piece o fpaper. They are just about adequate andcontain no examples. Aspect costs £9and is available from shops such as W HSmith.

Picturesque s lipped i t s Editor /As -sembler on to the market very quietly.The program is for the 16K and 48K

into operation. The usual ORG instruc-tion is included as part o f the instruc-tion set to define the address at whichthe assembled code should be put.

The program display is interesting,as the screen has a 40-column width andis split into several fields which corre-spond to those used in assembly lan-guage programming, together w i t h aline number fi eld. T he cursor recog-nises the end of one fi eld and jumps tothe next automatically. That makes the

'One of the most powerful assemblers whichwe have reviewed is produced by a small, andlargely unrecognised software house, CrystalComputing'.

Spectrum and is very powerful. I t iscomplete w ith a comprehensive usermanual which a complete beginner canunderstand.

The Editor is the part of the programwhich enters the source code. I t i spossible to enter code in the same typeof format as a Basic program, as eachline is given a line number. Unlike theBasic system o n the Spectrum, l inenumbers can be generated by the pro-gram automatically with the use o f theAUTO command. The use of line num-bers means that the source fi le can beedited quickly and easily.

When the source code has been en-tered correctly and there are no bugs inthe text, the assembler can be called


entered source code easy to understand.The Editor/Assembler is ideal for the

beginner and could also be a powerfultool in the hands o f a professional pro-grammer. I t costs £8.50.

The program which caused a buzz ofexcitement in the Sinclair User officesis probably one o f the most powerfulassemblers which we have reviewed. I tis a l l the more remarkable as i t i sproduced by a small and, unt i l now,largely unrecognised software house,Crystal Computing.

The program, Zeus, is a two-passassembler which allows the use o f thefull Z - 80 mnemonic ins truc tion set.Source code can be line-numbered andan AU T O line-number fac ility is also

available. The program is accompaniedby the best manual we have seen for anassembler. I t c ontains step-by-stepinstructions fo r enter ing and edit ingsource code. A n example is inc ludedwhich will, i f entered correctly, colourthe screen white, the current ink colour.

The use of an example in that way isgood, because if you make a mistake andthe program does not work you w i l lhave to re-learn the instructions. I f theexample works, users w ill have a goodunderstanding of how Zeus operates.

Zeus also contains several subrou-tines which can be used within sourcecode. They inc lude an I N K E Y S-t y p efunction and pr int a character routine.Other functions i n the assembler in-clude automatic re-numbering o f thesource fi le, outputting o f code t o aprinter, and the rec laiming o f 'o ld 'source fi les for further work Zeus hasbeen aptly-named by Crystal Comput-ing. I t costs £8.95.

There are very few good assemblerson the market although the big softwarehouses all c laim to have the best avail-able. I t is , therefore, surprising that asmall company like Crystal should pro-duce such an excellent assembler asZeus. T he reason may be that whilelarge companies spend their money oncolourful advertising, smaller compan-ies need to rely on very good-qualityproducts.

Artic Computing. 3 9 6 Jarnes Reckitt Ave-nue, Hull, North Humberside HU8 OJA.Picturesque. 6 Corkscrew Hill, West Wick-ham, Kent BR4 9B13.Crystal Computing. 2 Aston Way. East Herrington, Sunderland SR3 3RX.

31

After dealing with assemblers, John Gilbert turns his attention to theircounterparts, the disassemblers.

Making machine codeeasier to understand

THE TERM disassembler has

been used in many ways byprofessional producers of soft-

ware to describe their products andsome confusion has arisen as to what adisassembler should or should not do.The strict defmition of a disassemblercalls for a program which will translatethe numeric values of machine code intothe mnemonics of assembly language.There are other packages which do allkinds of things with machine code butdo not fulfil that definition. The correctterm for those packages is toolkit.

The mnemonics o f assembly lan-guage look like shortened versions ofBasic keywords. They are used to repre-sent the machine code numbers whichcomputers can understand but whichhuman programmers still find difficultto cope with in great quantities. It ismuch easier to understand a mnemonicsuch as RET, which means Return toBasic, than its machine code counter-part, which in this case is 201.

Most disassembler packages include amonitor program which allows the userto change machine code stored in RAMwhich has been disassembled. The dis-assembler makes the editing processeasier, as mistakes can be spotted quick-ly if the programmer has a disassemblyand not just a list of numbers whichhave to be sorted.

When computers had just been in-vented there was little software and

'The strict definition of a disassembler callsfor a program which wi l l translate thenumeric values o f machine code into themnemonics of assembly language.'languages such as Basic and Pascal didnot exist. Programmers had to use pro-grams which consisted of long lists ofnumbers. You can imagine the troubleif those programs did not work. Everynumber in the program would have tobe checked to see if it was correct.

The invention of assemblers and dis-

assemblers made things easier. Youcould enter code in mnemonic formusing the assembler and check the codeusing the disassembler.

When microcomputers were inventedthe disassemblers used on the largemainframe computers had to be alteredto work on the smaller systems, as manyof the instructions which were used onmainframes could not be used on mi-cros.

The first disassembler to appear com-mercially for the ZX-81 was ZXDB,from Bug-Byte. The company has builtits reputation with that package alongwith its ZXAS assembler and the reasonwas because it was cheap and ran on anexpensive computer.

The Bug-Byte disassembler was fair-ly standard in its performance. I t al-lowed you to specify the address, orposition in memory, at which you want-ed the disassembly to start. The pro-gram would disassemble one line at atime and you had to press NEWLINEfor the next instruction in memory to bedisassembled.

The ZXDB for the ZX-81 used twofields, or areas, on the screen in whichto display information. T h e fi rstshowed the address at which an instruc-tion was located and the second showedthe disassembly of the machine codeinstruction.

Other disassemblers, such as the Cry-stal Computing Monitor and Disas-

sembler for the Spectrum, use threefields. The extra area on the screen isused to display the numeric machinecode on which the disassembler is work-ing. It is a good idea as you can checkthe mnemonics and machine codeagainst each other-to see i f the disas-sembler is working correctly.

If a company produces both a disas-sembler and an assembler i t usuallymakes both programs compatible. Thatmeans that both programs can be putinto the computer to work together anddispenses with the need to load oneprogram to enter code and then load thenext to check that the code is correct.

Having both programs in RAM atthe same time will make programmingin machine code quicker and easier butthe amount of memory left for machinecode programs will be reduced drastical-ly. The advantages outweigh the disad-vantages, though, so it is a good idea tobuy a disassembler which can be usedtogether with an assembler.

Two problems occur when a disas-sembler starts t o produce questionmarks because i t has not been pro-grammed to recognise a machine codeinstruction. One disassembler whichdoes not follow the 1-80 instruction setis ZXDB from Bug-Byte. The programuses 8080 code instead of 180. Instruc-tions which are common on the Z-80 arenamed differently on 8080. For in-stance, LD in Z-80 is called M in 8080code. Those two names mean differentthings. The LD instruction means loada register with a value, whereas Mmeans move.

Trying to use a disassembler whichdoes not understand the full Z-80 in-struction set is like trying to use BBCBasic on a Spectrum or ZX-81. As BBCBasic is not the same as Sinclair Basic,the machine would not recognise theextra commands of the other language.As a result, when buying a disas-sembler, make sure that the programunderstands the complete Z-80 instruc-tion set and not just a subset.

Disassemblers can serve two pur-poses. They can be used to view codewhich you have stored in RAM or theycould be used to look at the ROM of themachine

With a good disassembler you couldobtain a listing of the complete SinclairROM for either the ZX-8I or Spec-trum. If you knew sufficient about ma-chine code you might also be able to tell

32SINCLAIR USER Annual 1984

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how the ROM works. To investigatethe ROM, or go bug-hunting in it, youneed the proper kind o f disassembler.Picturesque produces a monitor anddisassembler package which suits thepurpose. The disassembler has to pro-vide facilities for output to a printer,as the Basic interpreter and operatingsystem within the ROM are very lengthy.

A true analysis would have you jump-ing to different parts of the ROM whenJP, or JumP, instructiorls are indicated.jumP is similar to the Basic GOTOinstruction but there are many optionsavailable with that command and thedisassembler will help you to spot them.

Your disassembler should be capableof handling the RST instruction as it isused many times in the ROM. It meansReStarT and the instruction provides aquick entry point into the ROM forprogrammers using ROM routines i ntheir machine code programs.

The RST 10 instruction, fo r i n -stance, would send the computer con-

SINCLAIR USER Animal 1984

trol to the part of the ROM which dealswith the printing process. The routinesets up the machine to display onecharacter on the screen.

Most disassembler packages on themarket for both Sinclair machines arebeing sold mainly as an afterthought toassembler packages. The disassemblerhas a very important role in computing

'Many programs onthe market couldbe streamlined.'

and the second-class sticker with whichit has been labelled is unfair.

A disassembler should be a necessitywhen you are writing machine codeprograms.

I f you are to buy one, take as muchtime about choosing i t as you wouldwhen buying an assembler. I n manycases i t will be the disassembler which

will disappoint you wi th i ts perfor-mance and not the assembler.

For instance, the Bug-Byte ZXDBwas a breakthrough when i t waslaunched but with hindsight i t is some-what mediocre. The standard o f thedocumentation w i th ZXD B was fa rfrom satisfactory; as a result, the pro-gram was difficult to use.

Disassemblers are becoming morecomplex all the time and there is notmuch which can be done to improvethem. Many o f the programs on themarket, however, could be streamlinedto fi t into less RAM than is now thecase.

diCtronics. Uni t 2 , Shire Hill Industrial Estate, Saffron Walden, Essex, CB11 3A0.

Crystal Computing. 2 Ashton Way, EastHerrington, Sunderland. SR3 3RX

Picturesque. 6 Corkscrew Hill. West Wick-ham, Kent, BR4 BBB.

3 3

A PART FROM generalised spread-sheet programs o f the Vu-calcand Vu-fi le variety, there has

been l i t t le o r n o Spectrum softwarewritten for serious commercial applica-tions. Something of a new departure inthat direction is a specialised program,Beamscan, which is used to calculatethe sizes of steel beams used in buildingconstruction.

The program is used interactively,with the screen prompting the user atall stages and asking for details o f theloads. A diagram o f the beam is dis-played on-screen, which makes it clearexactly what information is being re-quested by the computer. The programseems w e l l error-trapped a n d user-friendly. When all the data is in, there isa wait o f about one minute while thenumbers are cmnched and then dia-grams are displayed giv ing shear forceand bending moment along the beam.

From its library of standard steelworksizes, the program recommends a choiceof up t o eight suitable sections w ithstress and deflection for each. A l l theregular r o lled s teel iois ts , universalbeams, universal columns and rolledsteel channels i n grade 4 3 steel arefeatured and a moment of inertia can beobtained for timber beams, from whichit is a simple matter to choose a suitablesection.

The beam must be simply-supportedand s ingle span. Cantilevers are notwithin the scope. That is perhaps theonly limitation worth mentioning. Anycombination o f point loads, distributedloads and uniformly-tapered loads i nany number up to a total of 99 can bespecified.

What is more, the distributed loadsdo not have to extend to the end of thebeam. With in the designated span o f0.3 to 20 metres, it is diffi cult to visua-lise any beam which could not be ana-lysed by the program.

Point loads frequently consist o f theend reactions of other beams. Both endreactions are given, which covers thatpoint and also is a great help in fi ndingthe stress in any supporting brickwork.

34

New ground broken bypowerful architects' aid

Sinclair machines are regarded still as little more than toys. DavidMarsh disagrees in this review of a new cassette

Also given are the maximum bendingmoment and shear force, the deflectionco-efficient, t h e permitted defl ectionand optimum moment of inertia.

That would mean that other types ofbeams, for example round or rectangu-lar hollow sections, could then be cho-sen using the data given in BS4.

For each beam size chosen, the Lir yand IYT ratios are iiven. together with

permissible and actual stresses,shear stress and deflection.

All that information can be put intothe form of a calculation sheet using theZX printer. That can then be submittedto the c lient or to the local authorityresponsible for checking the design. Al-though fu ll data is given on the resultsand the presentation is clear and con-cise, perhaps some local authorities mayconsider i t a lit t le too concise, in thatvirtually no details are given on how theanswers are obtained. I t is thereforedifficult to check the accuracy.

It is clear, however, from the printoutwhether or not the correct data has beentyped-in and, of course, that is half thebattle. The fact that a computer pr int-out is being submitted rather than themore usual written calculations shouldlend a reassuring air of professionalism.

It is also probable that in the perhapsnot-too-distant future when most calcu-lations are made in this fashion, variousprograms w i l l become widely-knownand generally accepted in the professionas being accurate. Some k ind o f type-approval system might even be possibleso that checking would be limited to thedata output.

That would be in line with the pro-cedure followed in other areas, wherecertain materials, for example buildingblocks, are given a certificate to indicatethat they comply with building regula-,ions. I f that make is used, then notimber proof is required that they meetthe requirements. Extending the con-,:ept t o software seems logic al andalmost inevitable.

Beamscan is supplied recorded onboth sides of the cassette and is suitablefor a 48K Spectrum, being about 35K.It is supplied with a well-written man-ual which guides the user through aworked example and describes the limi-tations o f the program as 999KN foreach load to a maximum total load o f10,000,000KN from the 99 loads men-tioned. They scarcely seem like limita-tions when there are other costlier beamdesign programs for bigger computerswhich cater for a max imum o f eightpoint loads while others cannot calcu-late the shear force or bending moment.

At £25, it appears costly compared tothe usual programs in Sinclair User butit is a more specialised item with a lowervolume sale than games or spreadsheetsand is much less expensive than any-thing comparable.

It should be ideal for small architec-tural practices o r the many one-manfirms involved in smaller-scale buildingworks. Neither is it necessary to pay afour-figure sum for the computer. Thewhole system — 4 8 K Spectrum, Z Xprinter, TV, tape recorder and software— can be up and running for s lightlyless than £300 and w i l l soon pay foritself in time saved.

Beamscan is available from Beams-can, 2 0 Vaughan Avenue, London,NW4 4H1.J. Tel: 01-202 8656.

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The technique o f 3D has been growing in popularity. John Gilbertfinds it is not always used in the best waysExtra dimension addsexcitement to gamesTHREE-DIMENSIONAL games

are increasing in popularity andsoftware houses are beginning

to see that 3D techniques have greatpotential in a market where Space In-vaders and Pac-man are rapidly becom-ing outdated.

Programmers are starting t o usesophisticated techniques t o achievethree-dimensional effects on the com-puter screen which seem more life-likethan the two-dimensional space-battlegames.

The effects are difficult to create, asthe programmer is working in threeplanes, or directions, instead o f theusual two. Most shapes are produced onthe screen using X and Y co-ordinateswhich correspond to the fiat horizontaland vertical dimensions. Three-dimen-sional shapes are constructed using anextra axis which, in theory, moves awayfrom or towards the computer screen.

The new axis is called Z and it is theinclusion of that dimension which givesthe three-dimensional figure its depth.When a 3D shape moves up, down andsideways i t uses the X and Y dimen-sions. When it seems to move towardsyou on the screen it is using the Z axis,which exists only i n theory, as thecomputer screen is flat and two-dimen-sional in shape.

I K Greye was the first company toproduce games using three-dimensionaleffects on the ZX-81. The game wascalled 3D Monster Maze and the play-er had to move around a three-dimen-sional maze to find the exit and also toevade the deadly jaws o f the dinosaurwhich prowled around the corridors.

Even those critics who dismissed theZX-8I as a child's toy had to admit thatthe program was innovative and well-presented. Monster Maze marked therise of the use o f 3D techniques onmicrocomputers as small as the ZX-81and Spectrum.

After the release o f 3D MonsterMaze, everyone could see the potentialof three-dimensional games and utilitypackages on small machines. Using 3Dtechniques programmers can portrayevents which seem real to computer

iInnual 1984 SINCLAIR USER AitHlial 1984

users when they are playing a game.Three-dimensional effects also hide

the inadequacies o f the computers onwhich games are played. The dinosaurwhich chased the player around a mazein the New Generation game was cre-ated using the standard ZX-81 characterset. That is not noticeable when thegame is being played and you could beforgiven for thinking that i t used high-resolution graphics.

The use o f 3D gives a game addeddepth but at the same time it can also beused to disguise a poor plot.

The game from New GenerationSoftware, 3D Knot, is an example o fthat. While the game has a basic plot i tis not deep enough when you strip awaythe 3D effects. That does not make it acomplete failure i n th is case bu t i tpoints to the fact that three-dimensionalgraphics are a means and not an end.

There are two types of three-dimen-sional effect. The first, and simplest toproduce, is shown in the Artic Comput-ing game for the 48K Spectrum, Com-bat Zo n e . T h e three-dimensionalshapes are shown as line drawings withno shading_ That means you can see all

the lines of the shapes, including thosewhich would normally be invisible i fcolouring and shading had been addedto the figures.

Combat Zone, l ike so many otherpieces of software for the Spectrum, isnot new in concept. It is a version of thearcade game o f the same name. Al -though the graphics are reasonable theanimation o f the line-drawn shapes isvery jerky.

The plot involves the player as thelast o f a race o f tank commanders.Enemy tanks a n d diamond-shapedspaceships are dotted round the land-scape and i t is the commander's job todestroy them.

The game involves plenty o f actionand credit must go to the programmerswho have managed to produce imageswhich do not bend out of perspective asthey move. Artic seems to have takenthe easy way out, however, as the pro-gram is so slow that it must use thosenotorious Sinclair line-drawing routineswhich are in the Spectrum ROM oper-ating system.

The Sinclair graphics routines are110T known for their speed, so it would

35

have been better for Artic to write newgraphics routines into the main body ofthe Combat Zone program.

The second type of three-dimensionalimage is produced reasonably well inthe Quicksilva 48K Spectrum game,Time Gate. The graphics for that typeof image are more difficult to produce,as the programmer has to shade andcolour the shapes to produce a picturewhich looks three-dimensional.

If the shading or the shape o f theimage is even slightly incorrect the pic-ture will appear to be distorted and theeffect wi l l ruin the playability o f thegame.

The three-dimensional effects createdin Time Gate show a slight distortion ofimage, which can be noted when anenemy ship approaches closer to theviewing screen of the player's ship. Theenemy seems to unfold its wings as i tgets closer and in some cases it appearsas i f the fixed wings materialise fromnowhere.

No doubt Quicksilva would explainthat as a feature of the game but all toooften features such as that are errors andare explained away too easily.

The ending o f Time Gate is disap-pointing, as the three-dimensional tech-nique seems to have been thrown out of

the window. When you have destroyedthe enemy you must approach its baseplanet. The planet becomes larger as i fan approach i s being made but thetechnique being used is so obvious thatit is embarrassing to watch.

The program uses what again ap-pears to be the Sinclair high-resolutionroutines to draw circles which startsmall and continue to grow bigger. Asthey increase in size the drawing pro-cess slows and the technique becomeseven more obvious.

It would have been better to do whatNew Generation did with 3D Tunnelon the Spectrum and create severalseparate pictures in memory to switchon to the screen one a t a time i nsequence. That will produce an animat-ed effect.

I f Quicksilva used that technique theplanet could have been produced i nhigh resolution at several stages of ap-proach and would have looked like areal planet and not a rope mat.

Time Gate has i ts technical faultswhere graphics arc concerned but i t isplayable. The 3D Tunnel from NewGeneration, on the other hand, haswhat can only be described as brilliantand imaginative graphics b u t i t i salmost impossible to play to the end.

The game takes you and your laser

base through an underground tunnelinhabited by rats, spiders, toads and avery impressive tube train. Unfortu-nately so much memory seems to havebeen used to create the three-dimension-al effects that the movement o f theplayer's laser base is awkward.

More attention could have been paidto that area of the game, as movement ofthe base is not smooth or quick enough.That is understandable, however, as agreat deal o f memory has been used toproduce the displays. Apart from thatproblem 31) Tunnel has the best graph-ics for a Spectrum game.

There are still very few 31) games forSinclair machines, although those avail-able give confidence that this sphere isdeveloping in the proper way.

In the next few months we could seea move away from 3D arcade games andinto 3D adventure games. There arealready a few graphics adventures onthe market but they do not use 3D.

As 3 D techniques are developed,computers will be better able to producesimulations o f the real world. Adven-tures wi l l become more exciting andarcade games more dynamic. The 3Dfield is, however, just starting to de-velop but it has a long way to go beforeperfect holographic images can be pro-duced on a small computer.

E D U C A T I O N A L S O F T W A R EPRICES DOWNPRICES DOWN

THE MICRO MASTER SERIESFOR ANY SPECTRUM

(designed and tested by teachers)The FOUR RULES OF NUMBER (for 7-13 years) — A cassette of 5 programmes designed toincrease calculation speeds to a very high standard. Computer adjusts to age and ability. Downto E9.90 (previously E11.70).LANGUAGE DEVELOPMENT SERIES (for 7-13 years) — 10 programmes per cassettedealing with VOCABULARY, SPELLING, VERBAL REASONING and KNOWLEDGE OFTHE ENGLISH LANGUAGE. Designed for 11 + , Common Entrance etc., but also useful forremediation Down to E5,90 (previously E7.90). Please state AGE when ordering Languagecassettes.One of each of the above — E12,70PREVIOUS CUSTOMERS/ENQUIRERS — MUST quote registration number to deduct asfollows from the above prices. 0000-0999 deduct E2•50. 1000-1200 deduct E1.50. 1201-1500 deduct E1.00.

Cheques/POs toMICRO MASTER, cio Dr Glasson,

94 Airedale Avenue, Chiswick, London W4 2NN.VISA purchases or enquiries Tel: 01-747 1373

TRADE ENQUIRIES WELCOME (sale or return)

SiNCLAIR USER Annual

Extend your 16kSpectrum to 48k forjustE2100.

And get a Freeprogram worthE450into thebargain.SP48, 32K Memory Extension with Program — £23.00

Now. our SP48 offers even better value.Because now, wire not only offering you the facility to up-grade your

16K Spectrum to 48K, we're also offering you the opportunity to be able to utilisethis vastly. m en d ed memo ry qu ick ly and easily.

For F93 all you need to do is plug the chip- set into the sockets providedby Sinclair on your issue 2 (or E35 for issue 1) arid you have a standard 48KSpectrum fullycompatible with all Sinclair add ons and very low in powercmsumCrle i s n o s o ld e ri n g r eq ui re d.

Fitting and remcKel are easy.And the SP48 cames our full warranty and is upgradable, on a part

exchange basis, to 5P80Then all you need to do is LOAD our specially written 48K guide

program. Beyond Hon-i nns ', a n d y o u r 4 8 K c o m pu t e r w i ll g u id e you t h ro ug h its

inemor(m

th no need to labour through manuals.This will saw you time, because we all know how easy it is to get lost with

memory mapsSP80 Paged 64K memory extension — E46

The fitting, power consumption and add-on compatibility are identical tothe 5P48 (Issue 1 Version E50l.

h can be used as a standard 48K, but software instructions can 9.4,itch to asecond page of 32K

But this is not recommended for the complete beginner.Yet it is of tremendous benefit to the serious user. And an SP80 FORT'

compiler will be available in late SeptemberFor a fit and test service at our premises E3, and by registered ptict E7.MAXIMEM VOL 32K — £39 (PLUS ONE USED IK

7X81) 64K — E59 (PLUS ONEUSE—ADThe MAXIMEM 32 and 64K is a modified ZX81 and not Just a RAM

pack It fits inside the case.We also give a six-month guarantee on the computer. regardless of the

age of your trade in 7:1481.The extra memory uses only a quarter of the power consumption of a

iSINCIA i It USER A wow' 1984

4 1 1 W : i“1 1 1 7 11 • 1 1 11

Is th e manual past chapter 24 a mystery toynu? Beyond Horizons'

shows 48K Spectrum MO's how to PEEK and POKE systemsvariables, how to manipulate the display file, bow to control t heattributes, how to find out how much spare memory is left and much.much more. With the SP48 this program is free. On its own. V4.50.

16K plug in memory and does not interfere with any standard add-ons, such asprinters RS232 or other interfaces.

Slowloader — E10The ZX Slowloader Is a software masterpiece that will help you to LOAD

Z)(81 programs onto a Spectrum, saving hours of typing timeThe Next Robotics Exclusive. The TrickstickThis r K,w ) o ys t i c k L S a r ew lu t io n in computer games control With our

Trickstick from one to eight players will be able to play simultaneously.It will be on sale soon — see our next advertisement

r 7p roduc ts on this order form are in stock at the time of going to press Same day dispa711

tor phoned Access and Visa ordersTo East London Robotics Ltd: Please send by return trick items required I• MAXIMEM 32K II:39)64K (E59) • Ikzysi• SP48 [Issue 1 E35) (Issue 2 123)L I s mo (Issue 1 E-50) (Issue 2 E,461E l SLOWICADER EIOE l "BEYOND HORIZONS- p r o g r a m D 1 5 0O Hee catalogue I SAE only)Postage0.65p 'enclosed cheque.130for M y A c c e s sN i s a l l o

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and interfacing.This thermal printer, now available in the U.K., is thestandard printer used with the American version otthe ZX 81. The printer plugs direct into the Spectrum

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a through port allowing the use of additionalrough the same connector.of the printer is 7% x 5% x 3% ins.

attractively packaged in a moulded mattblack plastic case.

A separate power pack is suppliedin a 21/ 2 x 3./ 7 x ins. case.

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Two switches mounted on the printer allow foron/off switching and also access to the test modeand paper advance commands.The printing speed in the self test mode is 120 linesper minute.The paper rolls are 4% ins, wide and 25 metres inlength.

E59 Price includes - Printer, power9e supply, full interfacing, one

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1


Hardware World

The ingenuity of the peripheralsmanufacturers has continued and SinclairResearch finally launched the Microdrive.Stephen Adams reviews another interesting

year for Sinclair users.

Stephen Adams summarises the add-ons

Ingenuity beatsSpectrum limits

40

T HE BIGGEST blow to users ofnon-Sinclair-produced e q u i p -ment was the announcement of

the Spectrum. I t knocked most mem-ory-mapped add-ons on the head, as noprovision fo r those devices had beenmade. That was because, unlike the ZX-81, there was no way of turning-off theinternal RAM from the expansion port.The only thing left was for producers toput things in the input/output map or tosupply RAM packs or RAM upgradekits.

The I /O map was already fu l l o fSinclair devices, allowing the use o fonly eight separate devices, i f theywanted them to be compatible with theMicrodrive. Nevertheless, ingenuitybrought forward a large number of newdevices after the initial shock had wornoff.

RAM ki ts for upgrading the I 6 KSpectrum to 32K are now readily avail-able for about £21. Fox Electronics, forexample, supplies a kit for £20.99 and ithas instructions on how to improveyour TV display. They are easy to fi tand now have simple instructions onwhat to do, i f you can overcome the fearof opening the case. The kits are usuallyidentical to the proposed Sinclair up-Microdrive

grade but will fi t only on model 2-typeSpectrums. East London Robotics canalso supply an extra 64K kit which ispaged.

For those with a model I Spectrum,identified easily by the grey keys, thereis the choice o f an add-on board madeby Downsway Electronics or the Spec-trum 32K RAM pack by Cheetah Mar-keting. The Spectrum RAM pack willalso fi t on to any other Spectrum, as itplugs into the expansion port.

Another memory-mapped deviceavailable this year was in a surprising

'Printers and otherhardware devicesmake the software

come alive'

place, inside the Spectrum I 6 K RO Mspace. I t was the Orme ElectronicsROM containing RENUMBER, blockdelete o f Basic lines and many otheruseful routines in a 2K ROM. That canbe very useful, as i t i s immediatelyavailable on power-up.

Sinclairhas a l s oprovided twonew devices foruse in the ROMspace, which shouldplease hardware a n dsoftware users. One is theMicrodrive Interface O n ewhich not only contains the con-trolling ULA and hardware to runthe RS232/network/highspeed cassetteMicrodrive but an extra ROM whichcan he used to write your own Basiccommands. The other is the ROM car-tridge system available with InterfaceTwo.

The RS232 can handle a printer easi-ly with its limited handshaking abilitybut sti l l is limited for input from anRS232 device, as all that is under soft-ware control and not a hardware chip.The network is a very simple arrange-ment which allows you to talk between64 Spectrums but I have no doubt thatsomeone will write similar software touse i t w i th the ZX-8 I through thecassette sockets. T w o books whichshould help in this respect are those byAndrew Fennel and Dr Ian Logan.

The Fennel one also contains an ONERROR GOTO machine code routinewhich should trap 90 percent o f Basicerrors and send them to a program lineto deal with them.

Sinclair h a s a l so launched t h eInterface Two, containing two joysticksockets which will operate the first orlast set o f five number keys. That willmean that software wi l l have to bere-written to use Sinclair joysticks, asthe accepted standard at the moment isthe one set earlier i n the year b ythe Kempston joystick interface whichoperates as an I/O device, depending forits decoding on A6 only being low.

SINCLAIR USER Artntdat 1984

i-:y

1-p.e-

attohechby

inesicI n c

theickor

willbe

, asit isby

uchfor

Irual 1984

M u c hsoftware h a s

already been con-verted to use it and I

cannot s e e softwarewriters wanting to do i t all

again. Programmable joy-sticksare just starting to reach the market,

which will eliminate the need to re-write the software.

For the Spectrum and soon the ZX-81, the Stonechip one seems to be best.For ZX-8I and Spectrum users, acheaper hardware-based version, thePickard controller, can be used as it fitsboth computers by plugging into thekeyboard sockets. The A GF versionuses crocodile clips to set up the fivekeys to be used; it is a little unstable butit plugs into the edge connector anddoes not require entering the machine.

The Interface Two also has a singleROM socket which allows you to useSinclair-designed cartridges. I t i s notknown whether software suppliers willwant to try to l i t normal ROMs to aport like this. That, and the fact thatrecording Microdrive cartridges i s aslow process, will l imit the amount o fsoftware available from software manu-facturers on Sinclair devices. EPROMsoftware for ZX-8 Is is available fromEprom Services and Audio Computers.

Both, however, concentrate on themachine code user and not the gamesplayer. The fall in price of the ZX-8 Iand the amount o f hardware availablefor it has started to attract the businessuser as a control processor for a robot orcontrolling some industrial process.That is because i t contains all the re-quirements of the development systemon one board — Z-80-A, one of the mostpopular processors, w o rk i n g a t

SINCLAIR t 'SER tirtnual 1984

Microdrive with Interlace

3.25MHz,TV interface,

cassette interfacefor program storage,

alphanumeric keyboard,Basic as well as machine code

monitor for designing programs,and an expandable memory map and

I./0 map.There is also a wide range of machine

code assemblers, dissasemblers,EPROM cards and blowers, RAM, bat-tery-backed memory already available,costing just a few pounds. That to theindustrial process manufacturer is pea-nuts, as a development kit from a chipmanufacturer would cost more than£200 with far fewer facilities. The ZX-81 costs only £45 with a massive I6Kmemory included.

Plain-paper printer interfaces for theSpectrum abound and Tasword, theword processing program, can workwith most o f them. Hilderbay andKempston p rovide software-drivenCentronics versions, while Morex pro-vides both RS232 and Centronics out-puts. Deans also introduced its versionof the Timex printer, which uses amuch better paper than the Sinclair,

gives a clearer print in both black andblue ink, and wi l l use Sinclair com-mands to control it, so there is no needfor extra software.

Printers and other hardware devicesmake the software "come alive" andthat combination makes the Spectrum avery powerful business computer.

That is the most important event o fthe year, as the more software which iswritten to use the large amount o fhardware, the more that hardware willbe used Voice output units, modems —to talk to other users or databases overthe telephone — RS232 interfaces andlight pens all rely on good software tomake use of them.

The Cheetah Marketing Sweet Talk-er, for instance, works better because itis accompanied by an instruction tapewhich not only demonstrates how to usethe unit but also shows the user how tostructure programs to make it easier touse in their programs.

Modems from Maplin, Ambit andMicronet — for Prestel — wil l allowusers of the Spectrum and, in the firsttwo cases, the ZX-8I, to talk to manyother computers. Some of them will beother types of computers, like the BBCand the Commodore 64. The others willbe maintained by public and privatecompanies w h i c h main ta in l a rg eamounts o f information and programson their computers.

Micronet 800 is a database main-tained on Prestel computers as a 24-hour-a-day, seven-day-a-week computerclub. It has hints and tips on Spectrums— Z.X-8 Is at the moment cannot use thesystem — as well as news, free programs

41

AGE programmable joystick

and a mail box facility. Keyboards andconsoles also have been making theirpresence felt as ZX-8 I and Spectrumusers want to upgrade their machines.Plastic cases from W H Smith are aboutthe cheapest containers at £3.99 andwill take a ZX-8I or Spectrum, as wellas a few add-ons. The d'Ktronics key-board and case or that from Fullersappear to be the most popular bu tneither will allow the use of the Micro-drive interface without taking i t out o fits case.

The Filesixty button set is a cheapalternative for ZX-81 users which givesthe advantage o f spring-loaded key-board the same size as that o f Sinclair,but without costing more than £10.

Colour for the ZX-8I is now availablein a simple form for all PA1. televisionusers — that is, most o f Europe. Theblack box requires only two wires toinsert between the modulator and thebreaking o f tracks and can be re-con-nected i f required. The rest o f the boxplugs into the back of the ZX-8I to giveblack characters on a choice of 16 col-oured backgrounds or coloured charac-ters on a black background from DDC.It is also more stable than the Spectrumand requires no extra memory to use it.It will work even on a I K machine.

One device which requires extramemory is the excellent High-res screen— 192 by 256 pixels — and user-defin-able graphics package made by Notting-dale Technology Centre. I t uses theZX-81 internal I K RAM for its systemvariables and 6 K o f memory for thestorage of the screen in the program. Nointernal wiring is required, as the unitplugs directly on to the back of the ZX-81.

For th e Spectrum, a u n i t h a sappeared which will be of great delight

42

to children and disabled users. It is theCurrah microSpeech unit which plugsin to the back of the Spectrum and, oncommand, will speak the key pressed.That happens during program input aswell as INPUT and INKEYS.

It requires no programming o f the

Orme Electronics EPROM read card

speech by the user. Speech output canalso be programmed by using S$ tocontain the alphones — sounds whichCheetah Sweet Talker

make up words — which ,ire then spok-en immediately. Thus input and outputcan be spoken rather than read.

Tapes have been causing problemsever since the ZX computers came intoexistence; the Spectrum is better thanthe ZX-81 but sti l l can be improvedwith some extra hardware.

Tape fi lters and switch-controlledSAVE and LOAD devices are availablefrom several firms, l ike Abacus andElinca. There have now been threeSpectrums produced by Sinclair. Themodel Is, which can be identified by thegrey keys or by looking through theexpansion interface and seeing an ICsocket on the left-hand side; the model2s have the large, black, ROM chipthere. Those Spectrums need their extra32K o f RAM mounted on a printedcircuit board before they can be put intothe computer. There are no SinclairRAM boards available for the machine.

The model 2s were re-designed com-pletely by a computer and the ULA waschanged to get rid of an extra IC whichhad to be inserted in the model Is, dueto a design error. The extra 32K o fRAM which can be added to 16K ma-chine now requires only chips to beplugged in to sockets on the board.Model Is and model 2s have had to havean extra transistor fitted to prevent aclash between the keyboard and theULA TV interface.

The latest model 3s have also hadtheir internal circuitry re-arranged andthe ULA updated to give a wider tuningrange on TV sets. I t has also causedsome software problems, as the key-board inputs are no longer held tobinary I — + 5 volts — when not in use.That was done to reduce the powerrequirements of the UL.A.

)WEEI TALKER

SINCLAIR USER Arrnidal

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During the year we published a series tohelp you learn how to program and

occasional articles on how to add gloss toyour listings. We now collect them to make

a complete programming course.

45

Follow route tobetter programsBasic Sinclair coding with John Gilbert

MANY PROGRAMS written

by beginners to computingshow a lack o f what profes-

sionals call structure. The structure of aprogram is the way in which i t is puttogether and the order i n which thecode—the language in which i t is writ-ten—is put down in the finished prod-uct.

To help the beginner with how tostructure programs so that they wi l lwork faster and occupy less memory, adatabase is constructed which can beused to store lists of information, suchas names and addresses or telephonenumbers. The information stored in thedatabase can be called back by typing-ina keyword which corresponds to theinformation sought by the user.

Before we start to do any coding it isimportant to know about flowcharting.A flowchart, such as the one in figureone, is constructed before coding to actas a guide to what the finished programwill look like. I f i t i s written aftercoding has been completed and beforethe programmer starts to search fo rerrors—to debug the program—it wi l lFigurcs I and 2

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be an aid in finding redundant code orcode which inhibits the flow o f a pro-gram.

The program fl ow i s the way i nwhich the program will be executed. Itis important to have that correct o rerrors wi l l continue to occur i n theprogram and the speed o f the programwill be slower.

The basic flowcharting symbols arehe Input/Output box, operation rectan-gle and decision diamond and a nexample of each is shown in figure one.

The I10 box is used to mark placeswhere an entry is made by the computeroperator, or when the computer dis-plays data on a screen or printer. Thebox can be used for all forms of input,including keyboard, joystick, o r evenpunched cards on a large mainframecomputer.

When debugging a program, checksfor errors should first be made at thosejunctions in the flowchart, as the boxesmark places where a user can crash aprogram by entering the incorrect infor-mation.

The decision diamond is the most

complex operation box in a computerflowchart—and the most necessary. Acomputer is distinguished from othermachines through i ts ability to makedecisions based on information. Usuallythe processing o f that information willprovide a simple yes or no answer. Theinflow to the diamond descends verti-cally and splits in two to provide theyes/no options.

The option which contradicts theprogram flow goes out to the side of thebox and can be directed up, to form aloop unti l the action has been per-formed correctly, or down i f alternativeaction is required to that o f the normalflow. Finally, the operation rectangle isused to show that the computer has toperform some kind of calculation. Thatmay b e adding numbers, assigningnumbers to variables, o r scanning astring of characters. The use of that andthe other boxes is illustrated in figureone.

Flowcharts usually are constructedbefore writing a program but it is a goodidea to draw up one from the finishedprogram to see i f the program flows as itwas originally intended.

When drawing a chart the boxesshould be balanced as much as possibleto the left and right of the main stem ofthe flow. The whole point of flowchart-ing is to create an easily-understooddiagram. The labels inside the symbolsshould be written in English and not inBasic.

The diagram in figure one uses sever-al decision diamonds and they branch toboth left and right. A flow on just one

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side of the diagram looks sloppy i f thereare more than two decisions to be made.

The way not to structure a flowchartis shown in figure two. The flow lines atthe side have been run together, makingit almost impossible to decide whathappens next. That is remedied easilyby making the chart longer and re-structuring the lines into separate boxesas shown in figure three.

When writing a program it is a goodidea to draw several flow diagrams. Thefirst would be an overall plan showingthe sections o f program to be writtenand subsequent diagrams would expandeach box to show the flow of the variousroutines.

A program is structured in a similarway to a flowchart. Most programs areconstructed i n the way figure oneshows. The technique is called modularprogramming because the structure isbroken into subroutines, o r sections,called modules.

The reason is to eliminate as manyGOTO statements as possible, o r tomake a CTOTO statement jump only to apart of the routine in which i t is situ-ated, i.e., to make what is termed a localjump, or the control routine at the topof the program.

The control routine consists o f aseries of GOSUBs. It is the part of theprogram which is used most, so it is thefirst thing the computer encounterswhen scanning the program. In thatway the program is faster in execution,so it becomes more efficient.

A control routine can have two dis-tinct structures. The first is used in a


game-type program. That type o f pro-gram wi l l execute routines by goingdown through each of the GOSUBs inturn and then returning to the begin-ning.

The other type o f structure is thatwhich we shall use for the database.The program wi l l fi rst jump to themenu routine where the user will selectan option. Control is then sent back tothe control routine and, using a series ofIF T H E N statements, the programwill go to the subroutine selected by theplayer. The control program will not godown through all the GOSUBs but willjump only to those specified by the userthrough the menu.

The database wil l function using akeyboard recognition function. Th euser enters a few words which act as akey phrase. The program will then lookthrough the list, or file, of informationin the program and, i f a match is madebetween the key phrase and part o f apiece of information, that piece of infor-mation wil l be output. The computerwill output al l information which i sassociated with the key phrase.

The program will also have to sup-port separate data files and be user-friendly so that anyone can use it. Theprogram menu wil l have search tiles,display entries, load or save files, andwill create new files. Th e programstructure will look like this from top tobottom, with the control routine at thetop.

The complete flowchart o f the data-base is shown in figure one. Using thatchart i t wil l be easy to translate each

operation into program code.With programs such as the database,

which is being constructed, the screendisplay is very important. The com-puter uses the screen to display infor-mation to a user.

Many people who use programs suchas databases or word processors wi l lknow nothing about how a computerworks or what i t expects as input. Themore information given to the user by aprogram the better. That does not meanclogging the screen with vast quantitiesof text. Instructions o n the screenshould be easy to read and well-spaced.The clear screen command should beused as often as possible to break-downinformation into easily-read pieces butat the same time the jump between one

of instructions and anotherbe almost transparent to the

screenshoulduser.

The text must flow naturally andthere should be no illogical jumps in theinstructions. That is a matter of experi-ence but the database has been designedwith clarity of instructions and promptsfor inputs in mind.

The most important instructionsshould stand out from the rest. That canbe done by liberal use of the commandsBRIGHT, INVERSE and FLASH onthe Spectrum and the GRAPHICSmode on the ZX-81.

Listing one is the menu subroutinefor the database. I t is written for theSpectrum but is easy to re-write for theZX-81. To do that take out the IN -

VERSE in 1020 and 1021, BRIGHT in1021 and FLASH in 1040. INVERSEcan be substituted with the GRAPH-ICS inverse lettering of the ZX-81 andthe ti tle MEN U should have spacesbetween each letter to make i t moreprominent.

The menu should not be surroundedby a border of a different colour, as thatcan confuse a user and make the screenlook crowded. It is also important not touse excess graphics commands. A dis-play with FLASH or INVERSE all overthe screen is just as confusing as i f theywere not there.

One other thing which people tend toforget is that they have the use of all thescreen. Do not cram things into thecorners o r sides o f a screen. Ti tlesshould be central and i f there is only aninput prompt on the screen, a goodplace to put i t i s the top left-handcorner.

Listing one is the first module of theprogram. I f there is a menu in a pro-gram it should be situated at the top ofthe code after any single or array vari-ables have been declared, as in line 100of listing one.

The menu module wi l l display theoptions available from the program. Askwhich you require, put the number o fthe option selected in a string variableAS, and transfer to the control program,also in listing one, at the top of the code.The control program, consisting o f aseries o f IF T H E N instructions,will then transfer to the subroutineselected from the menu.

The two other modules which arelisted are fo r LOADing data files—listing two—and SAVEing files- listingthree. They are for the Spectrum butZX-81 users can add toolkit routinesavailable from such companies as JRSSoftware. They will handle data files forthe ZX-81. I f you do not want to go tothat expense you will have to SAVE theprogram and variables together.

ZX-81 owners will have to break outof the program by erasing the left-handquote mark o f an input and typingSTOP. Then type SAVE "programname". When LOADing it back in, dothe usual load but do not press RUN.Instead use GOTO 200.

The SAVEd program can be verifiedon the ZX-81 by re-winding the tape,typing LOAD " " , and re-entering theprogram you have just SAVEd. I f theprogram has SAVEd correctly an 0/0error code will appear; i f not you willget another number error code. I f thathappens you will have to re-SAVE,

In the SAVE and LOAD routines afile name is asked for in lines 4010 and

48

5010. On the Spectrum a file or pro-gram name can be only 11 characterslong. To prevent the program crashingi f the name typed-in by the user is toolong, lines 4020 and 5020 will take onlythe first six characters o f a file name.The other letters are cut o ff or trunc-ated. Truncation is also used to cut theYES/NO inputs to Y or N.

The displays in both the SAVE andLOAD routines are important. Errormessages should be displayed i n thesame position on the screen every timethey appear. Every program shouldhave a standard error message area towhich the user will become accustomed.In the case of the database, that is in themiddle o f the screen. Also the errormessage in line 800 is BORDERed inred to warn the user that a specific inputis required.

Be careful about using the word "in-put" i n a prompt, as i t is computerjargon. The word "enter" is preferredas is shown in line 1040 of the database.

The prompts and information in theSAVE and LOAD routines may seemsimple and not worthwhile bu t thewriter knows about the internal work-ings of the program and what to enter.A newcomer to a program, on the otherhand, needs to be taken through it stepby step.

When a module o f a program hasbeen written it is a good idea to test it ona friend or relative who knows nothingabout computers. I f they can follow theprompts, leave the display as i t is; i fthey are confused, you know you havemore writing to do.

Data structuring comprises a series oftopics which most beginners l ike toleave alone, unless they are doing 0 orustifigt

A level courses in computer science.There is only one data structure in theBasic language and that is the array. Anarray is a series or table o f data itemswhich are grouped under one name.They are indexed using a number. Mostprofessional data processing programsare not written in Basic but in machinecode, because o f speed restrictions.Also, using data compression tech-niques in machine code you can entermuch more data into the machine thanwould normally be possible.

Databases written i n Basic do notoften use arrays as it is better to use longstrings of characters into which the datais put, or concatenated, as it is entered.In that way a user does not have tospecify the length of a file or how manydata items can be entered as a maxi-mum.

Arrays occupy more memory spaceand their length has to be fixed beforedata entry but sorting and searching iseasier to understand by using one- ortwo-dimensional arrays, as we can dealwith data one element at a time.

The fi le creation and data entryroutines o f the database being con-structed are shown in figure four.

The listings shown are for the Spec-trum but can be used for the ZX-81with the changes mentioned earlier.Line 100 of listing one has been alteredslightly to contain another array, cS.That array will hold the number of thenext available space in a file, the maxi-mum number of data items it is possibleto store, and the maximum length, incharacters, of a data item.

In the file creation routine the usercan define the fi le length and wordlength but i f they are over the maxi-

1@ D I N b $ ( 1 0 0 , 2 0 )2 O G O S L I E a t I A 03 0 0 I F a = " 1 " T H E N G O S U E 2 ' 0 04 0 0 I F a = • • 2- T H E N G O 5 1 . IB 3 00 0

5 0 0 I F a v s " 3 " T H E N G O 51..JB 4 0 0 0B O O I F a 4 ) 4 " T H E N G O S U B 5 0 0 07 0 0 I F a S = " 5 " T H E N G O 5 U S 6 0 0 08 0 0 I N K 6 : C L S - B O R D E R 2 : P R I N

T F L A S H 1 ; A T 1 0 , 0 ; " E N T E R i N U M B ER P 4 O 5 E 2 0 0

9 0 0 G O T O 2 0 01 0 0 0 P R P E R 0 : B O R D E R 0 : I N K 4 :L 51 0 1 0 P A P E R : B O R D E R 0 : I N K 4 4 : CL S1 0 2 0 I N V E R S E 11 0 2 1 P R I N T I N V E R S E 0 , B R I G H T 1 ,I N K 6 ; T A B 1 4 , •• H E M ) "1 0 3 0 P R I N T A T 5 , 7 ; " 1 S E A R C H F I L

' ; A T 7 , 7 ; " 2 D I S P L A Y F I L E; A T 9 , 7 ; " 3 L O A D F I L E " ; A T 11 , 7 ; " 4 - S A V E F I L E " , A T 1 3 , 7 ;-5 CREATE FILE

1 0 4 0 I N P U T " I N K 5 , F L A S H 1 ,E N T E R O P T I O N ( 1 - 5 ) " a1 0 5 0 I F a r = " " T H E N G O T O 1 0 4 01 0 5 0 R E T U R N

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F L A S H 1 ;-5 E T U P T AP E RND PRE5

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mum bounds, the computer will setthem automatically to 100 and 20 re-spectively. The data entry routine is notyet included on the menu. It is best toput it in the menu routine at line 750and set it to the Entry Subroutine at line7000. The menu display at line 1030will have to be changed so that "EN-TER D A T A I T E M " i s displayedunder "CREATE FILE".

When those alterations have beenmade, the enter routine at line 7000 canbe added to the listing.

Figures five and six show programlistings for two techniques which can beadapted for use with the database. Theyare two of many. The study o f datasorting techniques has interested aca-demics for a long time and some sophis-ticated algorit hms, step-by-stepmethods o f solving problems, haveevolved.

Figure five shows the Bubble o rShuttle Sort. I t is fairly simple to usebut very slow when dealing with largeamounts of data. It is called the BubbleSort because the data is sorted into a listin ascending order with items in theincorrect order 'bubbling' up to the top.The data items are sorted using akeyword, usually the first word of ornumber in the item. The Bubble Sortwill take the first character in an itemand compare it to the first character ofthe next data item.

You may like to change the routine tolook at the first three or four letters of aword. The routine can take anything upto three minutes to sort 50 items of data.If you are not concerned with the timeelement, the routine is easy to programand use.

In the program, line 8010 defines thepointers being used i n the routine.Pointer pl will show the first item onthe list and p2 the one beneath it. Thevariable sc will contain the number ofswaps made in one pass. When that iszero at the end of a pass, the sort isconcluded.

Line 8020 will send control to the


swap routine i f the first data item isgreater than the second. Line 8030 ad-vances the pointers and line 8040 willreturn to the menu i f the sort is com-plete. L ine 8070 returns control t omake another pass of the data.

The swap routine starts at line 8080and 8090 w il l swap the data itemswhich are in the incorrect order. Line8100 returns control to the main sortroutine and line 8110 informs the userthat the sort is complete. The routinecan be improved by adding a line tomake the computer display a message,such as 'SORTING', to inform the usera sort is taking place.

The Basic listing in figure four canbe used as a base for the other sortingtechnique known as the Shell Sort andthe line numbers which have beenmodified are shown in figure six.

The Shell Sort, shown in figures sixand 7b, is slightly more complex thanthe Bubble Sort but will run faster withlarge amounts o f data. I f a relativelysmall amount of data, for instance 100items, is to be used, the Bubble Sortwill do the iob just as quickly as theShell Sort.

For the Shell Sort the data file is splitapproximately into two halves, T h epointer pl is, as with the Bubble Sort,set to the first data item in the file. Thepointer p2 is set to the item halfway

Listing 3

5 0 6 0 P R I N T ' F I L E •S A V E D .-"-R E W I ND T AP E TO

A N D P R E S S N E W L I N E .-:

5 0 7 0 V E R I F Y C $ D A T A 1 a $ ( 3P R I N T " F I L E ' " ; C $

through the data file.The item pointed to by p l is com-

pared to all the items in the second halfof the fi le and swaps are made, asbefore, i f pl is greater than p2. Whenpl has compared item one to all of thelast half of the file it will point to thesecond item and again compare that tothe second half of the file.

The sort is finished when either p I orp2 arrives at the last item of the file andthe sc swap counter variable is O. Thatshows that no swaps were made in thelast pass through the data and the infor-mation in the file is in the correct order.

Both structures created by the sortroutines from figures five and six areillustrated in figure seven. As I havesaid previously, they are just two o fmany routines and i t is possible t ocreate several other sorts using the twobasic structures outlined.

There are many methods of searchingdata and no technique is better thananother but in the proper circumstancesone technique can be used in favour ofanother. The Binary Search deal is oneof the fastest searching routines and oneof the easiest to learn.

Obviously, speed is important in anysearching routine. Someone cannot waitfor an hour for data contained in a list of30 items to be retrieved by the com-puter. I f that were the case it would beeasier to search through a list on paper.

One method of searching a list wouldsimulate a person doing it by hand verywell. That is called the Serial Search—figures eight and nine—which can takeup to half an hour to search a list of 100names and addresses. T h e listing infigures nine and I I w il l run on theSpectrum but multi-statement lines,such as 2030, will have to be eliminatedfor use on the ZX-81. The routines willrun without the database but i f youwant to include one of them in the mainprogram you use lines 2000 to 2040,

The computer scan the data list, stem

5 0 0 0 R E M S A V E R O U T I N E5 0 1 0 C L 5 : I N P U T -E N T E R F I L E N A M

csg O l i I F c $ =

- - T H E N G O T O 5 01 0

5 0 2 0 I F L E N , C S > 6 T H E N L E T . C S = . c $ 11 T O 6 )5 0 3 0 P R U S E 1 0 : C L S P R I N T" F L A S H 1 ; - S E T U P T A P E A N D P R E 55 N E W L I N E " : P A U S E 05 0 4 0 P R I N T " I N V E R S E 1 ;-F I L E ' -; C $ - . B E I N G S A V E D5 0 5 0 S A V E c $ D A T A l a $ ( )

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49

by item, trying to match the key, a nameor telephone number entered by theuser with the items in internal memory.When a match is made the item will bedisplayed in full on the screen.

The length of time of the process willdepend on the speed o f the high-levellanguage, such as Basic, or the speed ofthe central processor i f the program iswritten in machine code. The numberof items in the list to be searched willalso be a factor in the amount o f timetaken by the computer.

I f you are planning to use only a fewdata items you could use the SerialSearch technique. The coding is simple.Use a variable as a counter to point toeach data item in the listing in turn.Increase the pointer by one every timean item is compared to the user's entryand no match is made. When the matchis made, print it to the screen.

The Binary Search is as easy to pro-gram as the Serial Search but the rou-tine is much faster, as it does not have tosearch every data item on the list. Thedata must be sorted in alphabetical ornumerical order and the computer willlook at the element at the centre of thelist of data as the starting-point—figure10—cutting the list into two halves.

I f the identification keyword or num-ber, typed-in by the user to trace anitem in a file, and the element in the filedoes not match, the computer has tocontinue its search. The computer willfind i f the alphabetic character or num-ber is higher or lower than the keywordtyped-in by the user. I f it is lower thecomputer w i l l take the last element

Figure 41 0 R E M A D D I T I O N A L P O I N T E R A R R A' C V A R I A B L E -p • P O I N T S T O N EX T

A V A I L A B L E S P A C E F O R D A T A .3 . 00 D I M ( 1 ( 2 1 0 . 2 0 1 D I M c ( 3 ) L

p = 15 0 0 0 R E M C R E A T E F I L E5 0 1 0 C L S I N P U T " H O U M A N Y D A T AI T E M S I N F I L E- 7 " d$5 0 2 0 L E T d = V A L d $

6 0 3 0 C L S • I N P U T " W H A T I S T H E M AX I M U M " ' " L E N G T H O F E A C H I T E M " , $: L E T e = o f I L e $ : I F e > 2 1 7 1 T H E N L E T

=2E15 0 4 . 0 D I M b $ f d , e )T C ( 3 ) = e5 0 5 0 P R I N TE R O F I T E M S " ;, • • " O K R Y ? "6 0 5 0 I N P U T /5 0 7 0 I F $ (.1 T O 1 ) = " n " T H E N G O T0 5 0 0 05 0 8 0 R E T U R N7 0 0 0 R E M D A T A E N T R Y R O U T I N E7 0 1 0 I F p T H E N G O T O 7 0 7 07 0 2 0 I N P U T -E N T E R I T E H 0 $ IF

b $ = • ' 5 1-O P T HE N R ET UR N

7 0 3 0 I F L E N b $ b $ l p 3 T H E N G O-ro 7060

7 0 4 0 L E T b $ t p 3 =12,$ L E T P =p * 17 0 5 0 G O T O t7 0 6 0 P R I N T " E N T R Y T O O L O N G . R E — Ef - r r-E R " • GO TO 10

7 0 7 0 P R I N T " C U R R E N T F I L E F U L L "0 T O L7 0 6 0 R E T U R N

examined and make that the end of' thefile, cutting away the other half.

I f it is higher, the computer will takethe last examined item as the beginningof the new, shorter file. The computerwill then find how many elements are inthe short file and divide it by two. Thenumber found will be the element at themiddle of the file and that is the elementlooked at next by the computer.

The process continues until a matchis made. Then the computer will print-out the full data item found in the file.The whole process is shown in figure 10and a listing of the resulting program isshown in figure 11. The listing can beused alone with a short data entry rou-tine o r with the database which hasbeen discussed as an example.

The listing in figure nine includes ashort entry routine so that you can testthe speed of the Binary Search. Line 30of the routine will check to see i f thekeyword entered at line 25 is the sameas the clement pointed to by variable Lin the data file, bt. I f it is less than thevalue o f the file entry, the pointer, L ,will move further up the list and i f it isgreater it will move down the list.

That part of the program is executedin lines 30, 40 and 50. The number ofthe file element in L must be an integer,so INT is used in those lines. The 0.5 atthe end of the lines mentioned must beadded to the INTeger in L to round itup and not down, as the Sinclair ma-chines do automatically during math-ematical operations.

In some cases i t is necessary to dis-play every item in a data file which has

: L E T C t 2 ) = d : L E

I N V E R S E 1 , " N U M B" - - " L E N G T H " , e

an entry which corresponds to thekeyword input by the user. That can bedone by adding an extra condition,IF T H E N , statement before line 40so that i f a match occurs the programwill continue to search the file in casethere are more corresponding items. If along file of data is to be processed anddisplayed it is a good idea to introducepaging into the display routine.

A list o f data must not turn over theend o f the screen so that a 'scroll?'message is displayed. T he computershould display the data in pages and atthe bottom o f each page a message tothe user should be displayed askingwhether he wants to see more. I f theuser types-in 'no' the program controlcan be returned to the main menu.

The display o f data is an importantfacet of any program and the guidelinesapply t o data output as well as dataentry. When a menu is used in a pro-gram and is not displayed for some timewhile other operations are taking placeit is important to let the user know whatother options are available at that time.That can best be done by displaying aband across the bottom o f the screenwith the options and the 'return to mainmenu' option on it.

The main point I want to stress isthat no t a l l users arc programmers.That may be less so now than in thepast with the advent o f home comput-ing but there are still some users whohave difficulty even getting around thekeyboard.

While it is important to know abouttechniques for file processing, it is more

Figure 5

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,3020 IF b$ (pl) 11 TO 1) )4%$ (P2) (1

T O 1 ) T H E N G O S U B 5 2 1 9 0. 50 '30 L E T p l = p 2 : L E T P 2 = p 2 + 1e t e 4 0 I F c = o A N D p 2 ) p T H E N G O T O

6 1 2 i ,8 0 5 0 I F p 2 ) p T H E N G O T O 5 0 2 0a 0 6 0 I F s c = 0 A N D p 2 > p T H E N G O T O

if215 0 7 ' 0 G O T O 8 0 2 08 0 5 1 0 L E T c =5 c + 15 0 9 0 L E T h S = 1 , $ t p. 1 ) : L E T b S ( P 1 .1 = bi p 2 ) L E T b $ I P 2 ) = hS 1013 R E T L M N8 1 1 0 C L 5 : P R I N T " S O R T E D " : P R L 1 5 E

21210

5 1 2 0 R E T U R N

Figure6F 0 0 0 R E M 5 H E L L S O R T .

M O D I F I C A T I O N S T OO NE

5 0 1 0 L E T p 1 = 1 : L E T p 2 = I N T. i c = 0

t7e0,3t3 I F p 2 ) p T H E N R E T U R N

F I S LIRE

f p / 2 )


Figure 7BUBBLE SORT STRUCTURE (BEFORE SORT)

ITEM NUMBER D A T A ELEMENT

23

SINCLAIRMICRODRIVEPRINTER

Figure 713 •SHELL SORT STRUCTURE (BEFORE SORT)

ITEM NUMBER D A T A ELEMENTUSER F I R S T ITEM IN FILE

2 H E L P L I N E3

important to know about the user inter-face, i.e., how the user will interact withthe computer and how he will cope withyour program. Once you can see thelikely reaction of the user and fit theprogram around your intended user,everything else will seem simple.

Now I want to take you back to showhow a program is constructed in a seriesof numbered steps. To begin, however,I want to discuss errors which can occurin programs, commonly called bugs,and how to rid yourself of them.

Much has been written about bugs.The term is derived from the early daysof computing when only large main-frame computers existed. They had tobe, and still are, kept in specially-pro-tected areas where dust or insects couldnot enter the machinery. I f computerswere not kept clean and serviced theycould often crash and data and pro-grams could be lost.

Most of the bugs encountered byprogrammers occur because programstructure is incorrect. The statementscausing the crashes are usually theFOR T H E N and GOTO lines.

When a program crashes, look at thereport code shown on the bottom of thescreen and find the line number wherethe computer ceased the R U N . AGOTO effect should be limited to oneroutine. If an error occurs at a certainline you have to look at that routine.

On some computers the system offersa command which prints-out the linenumber to which the computer goesduring operation. It is called the TRaceON (TRON) routine. It can be simu-lated on a Spectrum if you wish to addan extra instruction to each of thetroublesome lines. That instruction willmake the computer print-out each linenumber as it is executed.


MODEM S E C O N D ITEM IN FILE

It is not important that you knowhow it works but for those who areinterested the PPC system variable isPEEKed and the current line numberreturned from t he t wo addressesaccessed by the statement. The instruc-tion to be appended to program lines isPRINT P E E K 23621 + 256*PEEK(23621+ I).

That instruction can be put any-where any number of times. It is best toappend it to the end of lines.

It is also possible to chart the courseof FOR N E X T loops. It is done byprinting the variable used in the loop.The print statement should be put atthe end of the FOR statement andnot at the end of the NEXT statement.If you do the latter the count printedwill be incorrect. Both techniques areillustrated in diagram A—for GOTOsand—B for FOR . . N E X T.

The two techniques can be incorpor-ated together in a program and, with theerror message you get when the pro-gram crashes you should be able to

Figure 8

locate and correct the error.When talking about these techniques

and correcting errors, I must stressagain that they will be of help only ifyou have used the structuring tech-niques which have been explained.

I have detailed the pathway to struc-tured programming as a series of struc-tured steps:

First: Decide what type of programyou want and what you want it to do. Itis best to write it as a series of state-ments in plain English.

Second: Decide how you are t ohandle the task and whether it can bedone with your machine and with thelevel of experience you have.

Third: Break the task into a series ofheadings a n d sub-headings. F o rexample, most programs need someform of instructive display—an entryprocedure, a calculation procedure andan output procedure. They must be tai-lored to meet your needs.

Fourth: Draw a flowchart. Thatshould take a long time in many cases.It is a good idea to draw several charts,expanding the most important boxes inthe main one. In that way you will know

Figure 9

SEARCH KEYWORD: Sinclair

STAGE ONE:

STAGE TWO:

STAGE THREE:

SEARCH COMPLETED

Memory aidRead Only MemorySinclair Research

Memory aidRead Only MemorySinclair Research

Memory aidRead Only Memor ySinclair Research

2 0 0 0 D I M b $ ( 1 0 , 1 2 ) : R E M s' sET U P E_it t IMPLE D A T A F I L E2 0 1 0 F O P X =1 T O 1 02 0 2 0 I N P U T b $ ( k ) : R E M D A T A F I L EE N T R Y2 0 3 0 N E X T : P R I N T " F I L E E N T R Y CO M P L E T E " : P R O S E 1 0 0 : C L 5

04-(211 INPUT a $: REM SEARCH KEYLIOR

2 0 5 0 L E T a = 1 : R E M a =N U MB ER O F F lL E E L E M E N T B E I N G M R T C H E D2 0 6 0 P R I N T F I T 1 0 , 1 0 , F L A S H 1 ; " 5 EA R C H I N G "2 0 7 0 I F b $ ( a ) ( 1 T O L E N a $ ) = a $ T HEN G O T O 2 1 1 02 0 8 0 I F a = 5 T H E N G O T O 2 1 0 02 0 9 0 L E T a = a + 1 : G O T O 2 0 7 02 1 0 0 P R I N T A T 1 0 , 1 0 ; F L A S H 1 ; a $.;" N O T F O U N D- : S T O P2 1 1 0 C L 5 : P R I N T A T 1 2 , 0 ; F L A S H1 ; " I T E H L O C R T E D " F L A S H 0 , 1,11 a ) :

STOP

51

52

Figure 10

SEARCH KEYWORD; Sinclair

STAGE ONE

STAGE TWO:

STAGE THREE:AlphabetBubbleMemoryResearchSinclairZX 81

SEARCH COMPLETED

the concepts of the program before youbegin coding. If flowcharting does noth-ing else it will concentrate your mind onwhat you want to do.

A word of warning to peole who havetaken flowcharting to their hearts. Thetechnique is a means to an end and isnot an end in itself. I f you think acertain number of charts is necessary,draw them, but do not draw charts forthe sake of doing so, because you willoften be confused as a result.

Figure I I

Diagram A

Diagram B

AlphabetBubbleMemoryResearchSinclairZX 81

AlphabetBubbleMemoryResearchSinclairZX-8,

Fifth: Coding the program. Thecode, in this case using the SinclairBasic language, should be laid out inseparate modules. The control moduleshould be put at the top, as it is the partof the program which will be used most.Each module should be complete andGOTO statements should be local to amodule if possible.

Sixth: In long programs, bugs, orerrors, are liable to occur frequently.Bugs occur usually in the data entryparts of the program and in the flowstructure. Flowcharting and structuredprogramming will not dispose of allbugs but it will eliminate a few.

Now you should be able to writereasonably complicated programs. As Ihave stressed, there are two factorswhich are important, more so than someof the others, which are necessary tomake programming easier and moreenjoyable.

The first is structure. I f your pro-gram is well-structured it will containfewer bugs and will, in most cases, runfaster. The second point is that theprogram must be designed for ease ofuse, so that it can he used by someonewho knows nothing about computers.

If you have taken my advice, or evenmodified it using your own techniques,you are on the way to being an efficientprogrammer. You will find that you cando more and programming will becomeless of a difficult task and more reward-ing.

2 0 0 0 D I M b $ ( 1 0 /1 2 ) : R E M S E T L I P E

X A M P L E D A T A F I L E2 0 3 . 0 F O R k =1 T O 1 02 0 2 0 I N P U T b $ t k ) R E H D A T A F I L EE N T R Y20•Z30 N E X T K : P R I N T " F I L E E N T R Y CO M P L E T E : P A U S E 1 0 0 C L S2 0 4 0 I N P U T a : R E M S E A R C H K E Y L I O R

2 0 5 0 L E T L = I N T t 5 / 2 ) + 0 . 52 0 6 0 I F b S ( L ) 1 T O L E N a $.) = a $ T HEN P R I N T F L A S H I . ; " I T E M L O C A T E D; F L A S H 0 ; b $ t ) S T O P2 0 7 0 I F b $ 1 t1 ( 1 T O L E N TH

EN L E T t = I N T t r 2 ) + 0 . 5:3080 IF b$ LY (1 TO LEN TH

EN L E T 1 = I N T ( L * 2 3 + 0 • 52 0 0 G O T O 2 0 5 0

a $ 3 > a $

a $ ) < a $

1 0 P R I N T ; P R I N T P E E K 2 3 5 2 1 + 2 5f . * P E E ' . f 2 3 5 2 1 + 1 )

2 0 P R I N T P E E K 2 3 6 2 1 + 2 5 5 6 4 - P E E K( 2 3 6 2 1 + 1 ) . G O T O 1 0

1 0 F O R & = 1 T O 1 0 : P R I N T k2 0 P R I N T3 0 N E X T k

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ZX-81 owners will know, the I Kmemory provided in the basic

machine is often insufficient for eventhe simplest o f programs. That canleave the user frustrated as he thinks ofthe program he could have writen hadhe bought a 16K RAM pack. Thereforeany bytes of memory which can besaved in a program are of great import-ance.

There are many ways in which vitalbytes can be saved on a 1K machine.Once mastered, the user will discoverthat his compter is very versatile.

The ZX-81 1 K —1,024 bytes—ofmemory is filled with 124 bytes used bythe machine as its system variables; xbytes for the program; y bytes for thedisplay file—varies depending on howmuch is printed—and finally z bytes forthe variables defined during the pro-gram.

Each line in a ZX-81 program takesfive bytes as soon as it is entered—twobytes for the line number, two more forthe length of line, and one byte at theend for the NEWLINE. Anythingtyped in the line viill take up morebytes. Thus REM statements should beremoved as a needless waste of memory,as they serve no useful purpose exceptin a machine code program.

More memory can be saved by mak-ing one line out of two. Thus:10 LET G = 1520 IF INKEYS = "5" THEN LETG = G -- 130 I F INKEYS = " 8 " T H EN LETG = G + 140 GOTO 20can be replaced by10 LET G = 1520 LET G = G + (INKEYS = "8") -(INKEY$ = "5")30 GOTO 20

The removing of one line saves thefive bytes which are taken up by eachline and because of that saving theprogram will RUN considerably faster.

The method shown, making two IN.KEYS lines into one, is a type of condi-tional statement similar to IF, Thecondition inside the brackets can either

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be correct or incorrect. I f it is correctthe result of the brackets will be I but i fit is incorrect the result of the bracketswill be O. Therefore i f the user werepressing "8 ", the result o f the fi rstbracket would be I and the secondwould be O. Under those circumstancesG would increase by one. An expansionof the system is shown in the followingtwo programs:Original10 LET G = 1520 IF INKEYS = " 5 " TH EN L ETG G - I30 IF INKEYS = " 8 " THEN L ETG - G + I40 IF G < 0 THEN LET G = 050 IF G > 30 THEN LET G = 3060 GOTO 20After revision

Amnia/ 1964 S i N C I L i t USER An n u a l 1 9 1 0

10 LET G - 1520 LET G - G - (INKEYS = " 5 "AND G 0 ) + (INKEYS = "8 " andG < 30)30 GOTO 20

Probably th e most effective andpossibly the simplest method of savingmemory i s b y the use o f constantswhich are non-varying variables. First,you define a variable, e.g., 10 LET N

number used more than twice in theprogram, at the start of the program andwherever that number appears in theprogram substitute it with the variable.

As proof o f its effectiveness, 0.9Kwas saved in a 16K program by the useof only one constant—zero.

In a program line a number is storedas follows:Number as itappears inthe program

Byte E x p o n e n tcontaining B y t e126-(7Ehex)

Four mantissabytes

manage of the number ten1.0 1 2 6 1 3 2 3 2 . 0 • 0 • 0

When using a variable the number will

2 LET RINCODE " + "3 LET N*NOT P I4 LET U*VAL 1 12 "5'••LET W*SGN P I

6 DIM HO(VAL " 5 " )10 LET HioN20 LET S *N30 LET P000DE " 7 "40 LET Y *R50 LET XoRNDSR60 LET AO NN" 0 ( ta t tg 6,1 h1 )"

70 I F S>VAL "1E 3" THEN LET AO*" C ( . 2 Y19 7,g t)"

SCrIF S>VAL "2E 3" THEN LET Al io"W( Ott j r Q w )"

90 I F RND>VAL " . 9 " THEN LET Rs. CO ( 2 6 : - i g 5 ) "

100 FOR ToU TO R-W110 LET P*P4,<INKEYS*"0" AND P < 2

8)-(INKEYO*"5" AND P > N)1 1 9-C LS

'The removing ofone line saves five

bytes'take up only one byte of memory. Con-stants wi l l save memory only i f thenumber is used three times or more inthe program.

If, however, there is a number in aprogram which is used only once ortwice there are two more relatively effi-cient methods of saving memory in this.

l ithe number is betweeen 0 and 255,the function CODE can be used:10 LET T = 14can be replaced by:10 LET T - CODE " : "That wil l save four bytes o f memory.This method will be effective for thosenumbers which have a character as-signed to them but wil l not work forthose numbers 67 to 127, as they are notused in the ZX-8I character set.

The second method is for those num-bers above 255 or between 67 and 127.It makes use of the function VAL, thus:10 LET V••- 300would become10 LET V = VAL "300"The use of VAL will save three bytes ofmemory.

Numbers above 999 which can bewritten easily i n scientific notationshould be written in scientific notationin conjunction with VAL, which wi l lsave even more memory-10,000 c a nbecome VAL "10000" which can be-come shortened even further to VAL"1E4" which saves another two bytes.

After all those methods have beenemployed there are sti l l a few moreways of finding those extra bytes. A 0can be replaced by NOT PI. That takesup two bytes and saves five bytes overthe seven-byte number zero. A " I " canbe replaced by SGN PI. That uses onlytwo bytes and saves five bytes over theseven-byte number one. A "3 " can bereplaced by using IN T PI, which alsosaves five bytes.

Galaxians is aprogram which makes use of the whole

simple 1 K invaders

TO )JAT Y,g4J)"

)>*U THEN

JAT T , X JL

120 PRINT AT T , X ;RS (U,P-444J",";AT R, P J" (g q , g 6

130 I F Y>T OR ABS ( P - XGOTO VAL " 1 4 0 "131 P RI NT AT T , X ; " - * - "

ODE ASJCHRO N132 LET S*S.FLODE AS1 3 3-G 0T 0 CODE "L"

140 I F YONT THEN LET Y *R150 LET YT,Y-U*(INKEYS*STRS N ORY<R)160 LET Y * I NT ( X + R N D * 3 - W-( X > 26 )

4.<X<W))170 NEXT I200 I F H<S THEN INPUT HO2 1 0-I F H(S THEN LET H*S

220 PRINT AT RiPJ"X*X"JAT N , N;SCORE "JS J" H I " JHJ" BY " ;HO

230 INPUT AS240 CLS250 I F R S " " THEN GOT° CODE " * "

*I

54

screen area. There are four types o finvaders—on-screen dis play o f base,missile and alien plus score, highestscore and highest scorer's name. A l lthose superb features are achieved bysome power ful memory-saving p r o -gramming.

The features to note in the LISTINGare the absence of REM statements, asfew numbers used as possible and theuse o f four constants. Condit ionalbrackets are also put to their fullest use.

Four constants are used—R, N , Uand W which are set in lines 2 to _5.They are followed by the variables H$,H, S, P, X, Y and AS in lines 6 to 90.

The F O R- NEXT loop T is used tomove the invader down the screen.That is the most effective way of doingit.

Line 110 is the INKEYS line whichcontrols the movement o f the missilebast. T hat makes the fulles t use o fconditional brackets. N o t e tha t t h eAND inside the brackets stops the basefrom mov ing o f f either s ide o f thescreen.

In line 120 everything to be displayedis printed, for three reasons—memory issaved as all the pr inting is done in theone line; everything is displayed speed-ily and that leads to lit t le fl icker afterthe CLS in line 119.

Line 130 tests t o fi nd whether analien has been hit. Line 140 resets themissile when necessary. Line 150 movesthe missile upwards. L ine 160 movesthe alien horizontally to either side atrandom.

Lines 200 to 250 are used at the endof the game. Note that the CLS in line240 empties the display, thus leavingsufficient memory for the initilisationroutine in lines 20 through to 90, i.e.,memory is saved here by adding anextra line to the program.

To play Galaxians fi rs t R U N theprogram. Al ien after alien w i l l div etowards you. Use keys " 5 " and " 8 " tomanoeuvre your base. Key " 0 " to fire.You cannot move and fi re at the sametime due to the basic INKEYS. As yourscore increases the type of invader willchange. The random invader scores abonus of 200 points.

At the end o f the game i f the scoredoes not appear but instead an INPUTprompt appears that means you have seta new highest score and the computer iswaiting for you to INPUT your initialsof up to five characters. Once the scorehas appeared, press N E W L I N E f o ranother game; any other IN PU T w il lend t h e game. I n t ha t eventualityGOTO 20 w i l l s tart the game oncemore with the highest score retained.

Two into one willnow go on ZX-81Merging programs is made possible

0 NE PROBLEM until now withthe ZX-81 has been that when aprogram is loaded from tape any

previous program in the computer isNEWed and lost. That means that twoprograms, each saved separately o ntape, could no t be merged in to oneprogram. That would clearly be usefulfor, say , w r it ing subroutines whic hcould be written and tested separatelyand then merged with a main programon a different tape. The merge featurehas been included on the Spectrum andthe routine we developed means thatnow two programs can quickly be com-bined into one, with few restrictions onthe progtams so merged, on the ZX-81.

The procedure used is outlined andexplanations of the important steps aregiven. T he basic theory is to reservespace in the 16K memory by puttingRAMTOP, the address of the first byte,above the Basic system area, to a valuebelow the normal 16K value of 32768,and then transferring the first program,byte by byte, into the reserved space.

The second program is then entered,along with a routine which will retrievethe first program, add it to the secondprogram, and correct the values of linelengths—the third and fourth bytes ineach program line, see page 171 o f theZX-81 manual—and so on, so that theprogram will not crash or behave abnor-mally. Here is the procedure:

First, the user's first program is en-tered from cassette tape. Restrictions onthe program are that the line numbersmust all be lower than 9899 but greaterthan the greatest line number o f theuser's second program, yet to be loaded.That is so that when the two programsare merged eventually, the line numberswill be in the correct order and thecomputer w il l not crash. T o this pro-gram must then be added the final line:XXXX REM ENDwhere XXXX is the line number, whichroust be big enough to make it the lastline of the first program but must s tillbe less than 99. When the program isentered, the following direct commandsmust be entered, in the correct order:LET X = PEEK 16396 + 256*PEEK16397 - 1LET Y = 49230 - XPRINT Y

and the value of Y should be written orremembered. Then:POKE 16388, Y - 256*INT(Y/256)POKE 16389, INT(Y/256).

X, the value of D FILE—see chapter27 of the ZX-8I manual—minus one, isthe last byte of the program and is thusthe last byte which must be transferred.Y is the location where the first byte ofthe program will be stored-49230 waschosen as i t leaves a lit t le spare roombefore the end of the computer's 16K.and RAMTO P is poked to the value-the t w o P O K E commands—so thatwhen NEW is executed the transferredbytes w il l not be erased. That can beverified by typing:PRINT PEEK 16388 + 256*PEEK16389which should give the value of Y whichwas written.

Next the routine given in listing one.lines 9900 to 9920, is added to the firstprogram. Then type:GOTO 9900 followed by:NEW as soon as the computer has

finished the loop starting in line9900.

That routine copies the bytes of thefirst program into the memory, startingat the location given by the variable Y.NEW is executed to clear everythingexcept those stored bytes. To verify thatthe fi rst program is s till stored aboveRAMTOP, type:PRINT PEEK (your value of Y)*256 +PEEK (your value of Y + 1).

That should return with the first linenumber of your first program.

The next stage is to load your secondprogram f r o m tape. T h e programshould have a l l o f its l ine numbersgreater than 13 but smaller than thesmallest line number in the fi rst pro-gram, so that, again, the eventual lineswhen merged w i l l be i n the correctorder. Once that is done the routinegiven i n lis t ing two—lines I t o 13only—should be typed-in, and then thefollowing direct commands:

Listing L

9900 FOR F=16509 TO X9910 POKE Y- I6509+ F,PEEK9920 NEXT F

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LET Y= (your previous value of Y)LET K = PEEK 16396 + 256*PEEK16397and after those, REM statements mustbe typed-in, as lines 9900 and 9901 inlisting two. Each R E M statementshould include 100 Xs and there shouldbe 10 such REM statements for each1K o f the fi rst program which hasalready been copied above RAMTOP.

After one REM statement has beentyped-in, the other can be duplicatedquickly by using the EDIT facility andadding 1 to the line number each timethe line is copied. In that manner thecorrect number of REM statements canbe produced quickly.

As soon as the REM lines have beentyped-in, th e command G O T O Ishould be entered. The routine—lines 1to 13—will then transfer the first pro-gram back from above RAMTOP backto the main program, and when thereport code 9113—STOP executed i nline I3—is seen, the final. The mergedprogram can be tidied by deleting linesI to 13 and any left-over REM linesafter line 9900 may also be removed.

This is how the final 13-line routineworks:

The first two lines POKE RAMTOPto its usual (16K) value of 32768. Thatis so that as the routine progresses, thespace where the first lines were storedcan be over-written once those lineshave been re-transferred, and that en-ables longer programs to be merged.

Lines 3 to 4 check for the location ofthe REM command in the line:XXXX REM ENDat the end o f the first program, thatbeing the marker used to indicate theend of the first program, and the looppasses to line 5 with the variable Fbeing the location o f this REM com-mand. The variable K which was de-fined previously by direct command isthe location of the first byte in the firstREM line—line 9900—and is the loca-tion into which the first byte of the firstprogram is POKEd• The REM state-ments are used to reserve space belowthe Display File—we spent some timetrying to POKE the system variable DFILE but with no success—and the firstprogram is simply POKE into the loca-tions occupied by the REM lines. Thuslines 5 to 8 POKE the first programinto the space reserved by the REMlines, except for the C H M 118 whichindicates the last character in the line:XXXX REM ENDLines 7 and 9 are to clear the spacewhich was occupied by the first pro-gram. Finally, lines 10 and 11 count theextra Xs left over from the last REM

SINGAIR USER Annual 1984

line POKEd into and line 12 POKEsthe new length of the last line into theappropriate location. That means thatthe lineXXXX REM ENDwill finally become:XXXX R EM EN D ( + left-over Xsfrom the REM line)e.g., X X X X R E M E N DXXXXXXXX XXXXXand the appearance o f this is an indi-cation that the merging is successful. Ofcourse, i f the final REM line had exact-ly the correct number o f Xs, the linewill remainXXXX REM END

Using this routine we believe thatany two Basic programs can be mergedinto one. O f course, that does not ex-tend the limit of 16K imposed by hav-ing only a 16K RAM pack and it shouldbe noted that any variables stored willbe lost as the procedure is followed.

A large number o f direct commandshave been used where they could havebeen included in the two routines wehave given—listing one and two—sincei f the procedure is to be worthwhile i tshould be as short as possible.

For long programs i t i s obviouslysuperior to run the two routines i nFAST mode but that is not very infor-mative i f for any reason the computershould crash. Therefore until you areconfident that you have the procedurecorrect, we suggest that you take theextra time to run the routines in SLOWmode and keep an eye on the computer,even i f that takes a long time.

Listing 2.POKE 16388,0

2 POKE 16389,1283 FOR F Y TO 999994 I F P E E K F < >234 O R P E E K(F+ 1)< >42 OR PEEK (F+2 )< >51OR PEEK (F+ 3 )< >41 O R PEEK(F+4 )< >118 THE N NE X T F5 FOR t o F+ 36 POKE GsK—Y,PEEK G7 POKE G,08 NE X T G9 POKE G,010 FOR G K —Y+4 to 9999911 IF PEEK G < >118 THEN NE X T

12 P O K E F + K — Y - 2 , P E E K( F + K — Y - 2 ) ( F + G — K + Y-413 STOP9900 REM X X X X X X X X X X X X X X XX X X X X X X X X X X X X X X X X X X X XX X X X X X X X X X X X X X X X X X X X XX X X X X X X X X X X X X X X X X X X X XXXXXXXXXXXXXXXXXXXIO(XX9901 RE M (100 Xs)

to lines per IK stored program

Chess isin checkChris Whittington

BROADLY, there are two main

schools o f thought concerningthe problem o f programming

computers to play a game such as chess.The first and most dominant suggeststhat the way forward i s to use thenumber-crunching power and speed ofmodern computers to plough their waythrough as many possible paths arisingfrom a particular position, apply somesimple evaluation to the positions aris-ing in the path, and by that methodarrive at the best move. That approachhas become known as the brute forcemethod.

The second school of thought pointsto the highly-successful techniques al-ready applied by human players to theproblem and suggests that the best ap-proach would be to teach the computerto think like the best human players.We shall ca l l th i s th e knowledgemethod.

Faced with the problem of producingan effective chess-playing program for ahome computer such as the Spectrum,we can probably discard the knowledgemethod, i f only because we still have noreal idea how i t is that human grandmasters decide on their next best move.Indeed, what do we mean by best move?-there is no real choice at present other

than to use the brute-force method forsolving the problem.

Before we begin to explore a possiblesolution it would be best to examine insome detail the nature of the problem.Chess is a two-player game.

Whatever is good for one side is hadfur the other and vice versa; such gamesare known as 'zero-sum games'. Thatwill allow us to make statements such asthis move gives White a score of +250and thus gives Black a score of —250.

The game is played on a board o ffixed size with a fixed number of pieces;therefore we should be able to representthe board and pieces in some way in thecomputer memory.

The laws o f chess define how thepieces move, whether any position isillegal—for example, leaving one's kingin check—and how to decide on wins,losses and draws. In principle, there-fore, we should be able to define and

55

encode all the possible ways of moving achess piece, detecting checks and so on.

Unfortunately, f r om o u r po in t o fview, a number of different chess pieceseach move in a different manner andsome o f them move in some differentmanner i n special circumstances—forexample castling, en peasant.

I suspect that the apparently daunt-ing task o f defining all those possiblemoves for each of the pieces and encod-ing them into assembly language detersmany a budding chess programmerfrom beginning the task.

Some o f the early chess programs,and even some one can still buy, avoid-ed the problem by not implementingthe diffi cult portions, w ith the resultthat their program just never did castleor capture en passant.

The problem is not as daunting as itseems; one can work out routines to dothe task and there are published algo-rithms, and even lis tings, which canremove some of the tedium.

Since we have to decide on a bestmove we will need some way to evalu-ate, or attach a number to, any move.The conventional wisdom is t o keepthat pos ition evaluator as s imple aspossible, usually measuring the balanceof material and a few positional factors.It w i l l be o f interest t o note that thepositional evaluation w i l l be the onlypart of the program where chess knowl-edge and sk ill, as apart from a knowl-edge o f the rules o f the game, w il l berequired.

There has been muc h controversybetween strong chess players and coin-

'We must concentrateon refining our

search through thetree of moves'

puter programmers as to whether poorchess players can produce good chessprograms.

Certainly the best programs usuallyhave been prepared with the help o fstrong players and my feeling is thatsubstantial chess knowledge is o f mostuse after the program has been complet-ed and is being play-tested to tweak theprogram to its optimal performance byadjusting the evaluation function.

Then we have the problem of how toplough our way through all the movesto arrive at our brute-force solution. Inchess programmers' parlance that i sknown as the 'exponential explosionproblem' and i t goes something lik e

this:On the Spectrum we can evaluate a

position in, say, 25 milliseconds. In anyone chess position there w ill be around30 legal moves to consider. Thus to lookone half-move deep we need to evaluatesome 30 positions to arrive at the bestmove. That takes 30 times 25 millisec-onds, or 0.75 seconds.

To search two-ply deep we need tolook at 30 positions and a l l the 3 0positions arising from each of those-30times 30 positions in all w il l take 900times 25 milliseconds or 18 seconds.

By that reckoning to search three-plytakes nine minutes, four-ply takes 4.5hours, five-ply takes almost a week, andso on.

To achieve good results agains tstrong players, a program w ill need tosearch between eight- to 10-ply moves

deep. According to the previous calcula-tions an eight-ply search would take 400years to complete. Such a game, startingin pre-history might now be nearingcompletion.

I f we are to get anywhere using brute-force methods we must concentrate onrefining our search through the tree o fmoves to reduce or eliminate the blow-up effect. As an aside, a game such asdraughts, which has far fewer possiblemoves arising from any one position,

does not generate such severe problemsand thus machine-coded draughts pro-grams are more likely to defeat strongplayers than similarly-encoded chessprograms.

Fortunately there are several methodsto refine the tree search. The programsavailable on the Spectrum and ZX-8Ihave reduced the multiplication factorfor each p ly from about 30 times toaround four to eight times.

Adopting a top-down approach to theproblem, w e can formulate our fi rs tstatement o f the approach we shall betaking.

We shall use the method o f bruteforce with refinements, evaluating eachnode—position—in the tree o f movesaccording to a simple and fast evalua-tion function, biased heavily by materialfactors.

The program will need to be as fast aspossible and must therefore be encodedinto machine code. Basic would be fartoo slow.

We shall require adequate tools forthis task. As a minimum we shall need apowerful editor to work on the assemblylanguage tiles. Since those fi les may beas large as 4 0 K by tes - 100K byteswhen properly documented—we shallneed a disc-based system to hold them.

We shall need an assembler programto turn the assembly language files intomachine code and a monitor program tohelp remove bugs.

Only after the program is runningwithout bugs shall we consider puttingit on to our small home computer sys-tem.

Our next task will be to break downthe problem further and define particu-lar areas o f the program to which wemust attend.

Ma i n m o d u l e s-t r e e-s e a r c h a l g o -

rithm; move generator; is king in check?detector; position evaluator.

D a t a b a s e-h o w t o r e p re s e nt the

chessboard; how to store the moves andpositions as we move up and down thetree; tables containing knowledge aboutthe position which can be used by theposition evaluator.

REFERENCESChess skill in man and machine, Editor, PeterFrey. Publisher, Springer-Verglag.Sargon, a computer chess program, Au -thors, Dan and Kathe Spracklen. Publisher,Hayden,The machine plays chess? Author. Alex Bell.Publisher, Pergammon.Think like a gr and master. Author . Al ex-ander Kotov_ Publisher. Botsford.


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Putting brainsinto monstersDonald Hughes writes

HOW MANY TIMES have you

wished you could write adven-ture programs? How many

times have you started, only to cease anhour later, frustrated by the awful com-plexity? I f the answer to the secondquestion is too many times, you areprobably approaching the problem fromthe wrong end.

An adventure game should be splitinto two parts—the brain and the adven-ture. •

The brain is the interactive part o fthe program which communicates withthe adventurer, answers queries, picksup items and drops them. The adven-ture can then be rendered into datasuitable for the brain.

The brain is a loop, normally large,which uses a READ statement to takedata for the adventure from successiveDATA statements. Normally the brainprogram will run i ts course once peradventure location, so when a locationis left, i t draws new data from theadventure. Using such a brain, eachadventure location can be stored in oneDATA statement of set format.

You must start b y deciding what

adventures

initial intelligence the brain will have. Irecommend you do not aim for any-thing more intelligent than the simpleexample. The example brain under-stands only one word at a time and theymust be keywords. I f the commandgiven is not a keyword, the brain is sounreceptive that i t proceeds merrilyalong as i f it had found a keyword. I t

'Do not expect yourfirst brain to runadventures of a

professional standard'works, though, and you can write ad-ventures, using the brain, in two hours.

Starting with a brain similar to theexample, you can add keywords slowlyuntil i t i s reasonably intelligent, andyou can have complex adventures, butstart simply, or you wil l find yourselftrying to debug a program which doesnot work far enough for you to find thebugs, let alone see what is not correct;and it will be back to the frustrations.

Do not expect your first brain, or theexample, to run adventures o f a pro-fessional standard; that is not the aim—it is to let anyone starting on a Spec-trum have fu n w i th programs theythought were only i n the realm o fprofessionals.

A simple brain operates in this way.The text of the first location is read in;the number o f items in a room is readin; the items in the room are read into astring array, then printed-out alongwith a copy of the text; the monster inthe room i s read in , along wi th i tsstrength. Logically, before the playermay take an item he must defeat themonster. Once the monster is dead, thebrain asks what function is required.The functions understood are:Take—to pick up an item.Drop—to drop an itemInve—produces an inventory.Leave—leaves the room.

Those instructions, combined withan imaginative adventure, are sufficientto entertain.

SCORE SHEET

Due t o t he l i m i ta ti ons o f the br a i n,here is how to score your per for m ance inthis adventur e:

I f you cheated with the priests, 0; i f youtook the heavenly being, 0; i f you died, O.

You should have wi th you a sword, bagof coins, box o f coins, r uby a n d Spec-tr um — the most valuable item_

I f y ou ha v e a l l fi v e , excel l ent; onl yfour , good; onl y thr e e , fa i r ; onl y tw o,bad; onl y one— have you not pl ayed a nadventur e game previously?

10 LE T t o,9 5 015 D I M 5 ( 1 0 , 1 020 LE T N.q2195 R E M L i s i c fi r s t v i e w97 CLS

100 READ t e105 I F te l m "e nd" THE N GO TO 9 9 0 0118 P R I NT t $120 P R I NT " I N T H I S ROOM THERE I

S"130 PEAL r c135 D I M s g r r c , 4 0 )140 FO R 4 • 1 T O r c150 READ 1 4 ( 4 )160 P R I N T 5 1 1 ( 4 )170 NE X T 4180 REM m o n s t e r s190 READ mal.m195 I F m $ • " n o n e " THE N GO TO 2 6 5200 P R I N T "Y O U S E E A

DO YOU WI S H TO F I G H T/ P U N < F / P ) "210 I N P U T w $2 2 0 > I F w i l W f." T H E N G O T O 4 50

230 I F 6011.."h" THE N P RI NT " B Y WHICH E X I T DO YO U W I S H TO MAKE YO U12 ESCAPE"

240 I N P U T e S250 GO TO 4 3 0260 P E N r e t u r n f h o m fi g h t270 P RI NT "Y O U MAY NOW TAKE O P

DROP AN I T E M O P Y O U MAY LE AV E "288 I NP UT c S290 I F c e " t a k e " TH E N GO TO 5 7 0

300 I F c e w " d r o P " THE N GO TO 6:;:03 I 5 I F c e • " l e x u e " THE N GO TO 4 1

0320 I F c e - " i n v e " THE N GO TO 8 2 0390 P R I N T " U S E commANDs TAKE • O

P O P . I NV E , LE AV E "-340 GO TO 280

400 REM4 1 0 P R I N T " I N WHI CH DI RE CTI O N"4 2 0 I N P U T c e4 3 0 GO TO 9 0 0 04 4 8 ',S T OP

4 5 0 REM fi g h t i n g4 6 0 P R I N T " T H E " , 0 1 1 . " HAS " . s , . "STRENGTH P T S , D 0 v o u S T I L L W I S H

TO F I G H T "478 P R I N T - ( y / N ) .480 I N P U T P $490 I F f g " . 4 " THE N P R I N T " B Y W

H/ CH E X I T DO YOU W I S H TO MAKE Y OUP COWARDLY ESCAPE"

495 I F f S . • w " TH E N GO TO . 1 05 0 0 GO TO 2 4 05 1 0 L E T 2 5 - ( m i t < P ND. 1 . 1 > )520 I F T H E N P R I N T " H A HA

YOU AP E DE AD, BY E "525 I F s > 0 THE N GO TO 5 4 0530 GO TO 4 4 054e P R I N T " T H E " f t m e," I S D E A D "

5 5 0 GO TO 2 6 05 6 0 REM t a k i n g570 P R I N T "WHAT DO YO U W I S H TO

TAKE"

5 7 5 > L E T F I P 44. 15 8 0 I N P U T Y W n,582 I F N> . . 5 THE N P R I N T ° Y O U Mlie.

T DRO P AN I T E M BEFORE YO U MAY T AKE AG AI N"

6 0 0 P R I N T "Y O U MAY NOW CO NTI NUEPi

G l e 17 . 0 TO 270

6 2 0 REM d r,: . P P i n 96 3 0 P R I N T "WHAT DO YO U W I S H TO

DROP"635 D I M d $ ( 1 0 )640 I N P U T D $650 FO P C • 1 T O N660 I F de k . v i t e c, T H E N G O T O 71 8

670 NE X T c688 P R I N T "Y O U DO NO T OWN SUCH

AN I TE M "690 P R I N T " T R Y AG AI N"700 GO TO 6 9 0710 FO P 2. . . c TO n720 L E T . 0 1 1 ( r.. ' 1 0 1 5 ( :41 )

73e NE Y T 7735 L E T n ! 1 - I740 P R I N T " O . K . "750 P R I N T " D O Y O U WI S H TO TAfr E

AN I T E M 1 • .,• 0 "

760 I N P U T C S770 I F cl i lK)"14" TH E N CO TO 6 0 0780 P R I N T "WHAT 7 ."790 L E T n..n-1.18 0 0 I N P U T i n81P Gr ) TO e o e

bowl 1984 I SINCLAIR USER Annual 1984

58

The brain then asks a question, de-pending on the keyword used. Fo rexampk, What do you want to take?Type-in, e.g. "sword". What do youwish to drop? Type-in, e.g., "coin". I f

INVE was used, the brain prints-out aninventory.

When LEAVE is typed-in, the brainasks in which direction. That is merelyfor show as, when a direction is typed-in, i t PRINTS "you are going to thenext room", PAUSES for a second;CLEARS the screen; and RESTARTSTHE LOOP, reading in the next por-tion of DATA.

One of the first improvements to thebrain you should make is a way o f

flipping through the DATA to find anyadventure location, so one can go N, S,E, W. The example brain suffices with-out that.

In writing adventures, first examine

'A simple brain operates by reading in the textof the first location; the number of items in aroom is read in; the items in the room are readinto a string array; the monster in the room isread in, along with its strength'

the listing. The brain is obvious, lines95 to 850. Rernovethedatastatements,1000 to8000. Insert your own data, inthis form:1000 D ATA " A " , " X " , " B " , " B " ,

sA is text describing the room; X is

the number o f items in the room andmust be equal to the number of stringsfollowing it; B is a string, an item in theroqm; M is the name of the monster; Sis the strength o f the monster. Should

you not want a monster, type-in theDATA positions for M and S "none", 0

Try typing-in the adventure detailedinto your Spectrum and playing it to seethe possibilities, within the limitationsof even a simple brain. You should haveplenty o f fun. After that, write youradventure for it. Real beginners shouldbe very careful when typing-in the ad-venture; a bug will make itself immedi-ately and annoyingly apparent.

To use the brain on a ZX-81, you willhave to circumvent the "who needsREAD statements" problem.

Combat works th i s w a y ; y o u rstrength is S; monster strength is M. Incombat, this operation takes placeLET S S-(M*(RND-1- I))which means a random figure varyingbetween M and nearly M*2 is removedfrom your strength i n defeating themonster. For different adventures, dif-ferent Ss can be given, so only bychoosing carefully what to light can youwin.

List of variables used in the program.

T$ =textre -number of items in a roomAS =array of room contentsMS=monmer nameM g•monster strengthWS=answer to tight/run optionCS =command wordC =used in loopsZ =used in loopsS - y our strengthFS =answer in fight routineYS =answer in take routinedS answer in drop routineeS -exi t direction

10 LE T s-. 3 5 015 D I M y e r 1 0 . 1 0 , •20 L E T N e 095 P E N t . l s i c fi r s t v i e w97 CLS

100 RE AD t $105 I F t i e " e n d " THE N GO TO 9 9 0 0110 P R I N T UV120 P R I NT " I N T H I S ROOM THE RE I

S"130 READ r c135 D I M a l l ( r c . 4 0 )140 FO R g e l T O r c150 PEAD 5 4 ( 4 >160 P R I N T s i l l (q170 NE X T q180 P E N m o n s t e r s190 READ mO,m195 I F m i l l e"none" TH E N GO TO 2 6 5200 P R I N T "Y O U S E E A

DO YOU WI S H TO FI G HT/ P UN < F / R ) "210 I N P U T w $2 2 0 ) I F w I l e "c " THE N GO TO 4 7 0230 I F w i l l e"r " TH E N P R I N T " B Y U N

ICH E X I T DO YO U WI S H TO MAKE Y O UP ESCAPE"

240 I N P U T of t250 GO TO 4 3 0260 REM r e t u r n f r o m fi O h t270 P R I N T "Y O U MAY NOW TAKE O P

DROP AN I T E M O P YO U MAY LE AV E "280 I N P U T •290 I F c e e " t s k e " THE N GO TO 5 7 0

300 I F c $ e " d r o P " THE N CO TO 6 2 0315 I F c $ e " l e a v e " THE N GO TO 4 1

0320 I F o i l l e " i nv e " THE N GO TO 8 2 0330 P R I N T "U S E COMMANDS TAKE • D

POP.. I NV E , LE AV E "340 CO TO 2 8 04 0 0 REM410 P R I N T " I N WHI CH DI RE CTI O N"4 2 0 I N P U T4 3 0 GO TO 9 0 0 04 4 0 S TO P450 REM fl O h t i r c )460 P R I N T " T H E " , m . . " HAS " . m , "STPENCTH P TS , DO YO U S T I L L W I S H

TO F I G H T "470 P R I N T " ( Y / N "480 I N P U T f $4 9 0 I F f g e " w • T H E N P R I N T " B Y W

H/ CH E X I T DO YO U WI S H TO MAKE Y OUP COWARDLY ESCAPE"

495 I F f $ e " v " THE N GO TO 3 1 0500 GO TO 2 4 05 1 0 L E T s e s - ( m t f R N D + I ) )5 2 0 I F s r e 0 THE N P R I N T " H A HA

YOU ARE DEAD.. BYE"525 I F s > 0 THE N GO TO 5 4 05 3 0 GO TO 4 4 0540 P R I N T " T H E "JP I S J" I S DE AD"550 GO TO 26 (3560 REM t a k i n i l5 7 0 P R I N T "WHAT DO YOU W I S H TO

TAKE"

5 7 5 >LE T N e N41580 I N P U T Y O ( n )582 I F N > e 5 THE N P R I N T "Y O U NUS

I DROP A N I T E M BEFORE YO U NAY T AKE AG AI N"

6 0 0 P R I N T "Y O U MAY NOW CO NTI NUEPI

6 1 0 GO TO 2 7 0628 RE M dr oP P i nQ6 3 0 P R I N T "WHAT DO YO U WI S H T U

DROP"6 3 5 D I M d $ ( 1 0 )6 4 0 I N P U T D o6 5 0 FO P Ce 1 T O N6 6 0 I F d I l l = s 0 r c, T H E N G O T O 7 1 0

6 7 0 NE X T cEeet P R I N T "Y O U DO NO T OWN SUCH

AN I TE M "69e P R I N T " T R Y AG AI N"700 CO TO G 3 0710 FO R z e c TO n720 L E T . 9 1 1 ( z ) . . v $ ( z 4 1 )7 3 0 NE X T z735 L E T n e n - 17 4 0 P P I N T " O . K . "75e P R I N T "DO Y O U W I S H TO TAP E

AN I T E M ( s l / n ) "76e I N P U T C I7 7 0 I F c e r > " w " THE N CO TO 6 0 07 8 0 P R I N T "WHAT 7 "790 L E T n e n e l8 0 0 I N P U T w S ( n )8 1 0 GO TO 6 0 0


Sorting through memoryfor some useful addressesS YSTEM VARIABLES are the

bytes i n memory from address16384 to address 16508 in RAM

on the ZX-81. They are used by thecomputer to remember certain thingsabout i ts workings, such as where toprint next.

You can make use of some of them inyour programs either by reading theirvalue—PEEKing—or replacing themwith new values—POKEing—so as touse the information they contain o rmake the computer do something i tmight not otherwise do.

Not all o f them can be used in thisway; some may ignore you, whereaschanging the contents of some of themmay cause strange effects, like making amess of the screen display. At worst, alittle nasty known as a crash may becaused.• 16384 E R R - N R ( E r r o r rep o rtnumber). The value contained in ad-dress 16384 determines the report code.If you POKE a number into 16384which is anything other than 255, theprogram will stop and display an errorcode, which may be non-standard butmeaningful in some way.

For example, i f you wanted to ar-range that i f the user entered an incor-rect value the program stopped witherror U—standing for USER ERROR—you w o u l d arrange t h a t P O K E16384,29 was executed. To determinewhich value to POKE, remember that16384 has a value o f 1 less than thereport code.

The error report code can be sup-pressed by POKEing certain values intothis system variable. That may be use-ful at exhibitions, where a report codemay be an unsightly distraction fromthe rest o f a display. Experiment withPOKEing some o f these numbers into16384: 43, 70, 72, 73, 74, 75, 76, 77, 7981, 82, 89.•16386/7 ERR-SP. This system vari-able contains the address o f the firstitem on the machine stack after theCTOSUB returns. Wi th PEEKing thistwo-byte system variable you can checkhow many CTOSUB return addresses arepresent on the stack, for example tocheck i f any bug in your program hadbeen causing i t repeatedly to call andjump out of subroutines. Here is how to

Dilwyn Jones explains the workings of systems variables1K ZX-81.

The value contained in RAMTOPalso determines how the display file—screen picture—is made up after CLS.If the value in RAMTOP is less than19712-16388 = 0 , 16389 = 77—thedisplay file is contracted to minimumsize consisting o f only 25 NEWLINEcharacters. I f RAMTOP is 19712 orhigher, the display file is expanded byfilling with spaces. A contracted displayfile has the advantage that i t takes fiveseconds less to LOAD or SAVE pro-grams.• 1639112 PPC . Contains the l inenumber o f the statement being exe-cuted. I t could be used as an aid todebugging a program which has com-puted CTOTOs/GOSUBs all over theplace; a few PRINT PEEK 16391 +256 x PEEK 16392 statements hereand there could determine whether ornot th e program went where yo uthought i t should do.

In the last line of a program it deter-mines the line number to be printed bythe report, e.g., 0/100. You may like touse that to print a score on the screen atthe end of a game.4,16396/7 D- F IL E. Contains the ad-dress of the start of the display file. Thecharacter pointed to is the first NEW-LINE character i n the display fi le.Since the display file floats above theprogram in memory, you can use i t Cotell you where the program ends, givingyou an indication o f the length o f theBasic program, since the Basic programstarts at 16509: PRINT PEEK 16396+ 256 x PEEK 16397-16509 will tellyou the length of the program in bytes.

I f you want to PEEK/POKE into thedisplay file for any reason, this systemvariable helps you by telling you wherein memory it starts.• 16398/9 DF-CC. Tells you where inmemory the current PRINT positionlies. PEEK 16398 + 256 x PEEK16399 gives the address in RAM of thecurrent PRINT position. That could bePOKEd to change the PRINT position.Alternatively, i f you PEEKed the ad-dress o f the PR IN T position, youwould obtain the CODE of the charac-ter already at that position—useful fordetecting collisions and so on in games,or for programs which require a screen

SINCLAI R USER Annual 1984

check:PRINT (PEEK 16388 + 256 x PEEK16389)—(PEEK 16386 + 256 x PEEK16387)4,16388/9 R A MT O P. R A MT O P isthe address of the first byte of memoryabove that used by Basic. NEW oper-ates only this far, so anything placedabove RAMTOP i s safe from everyBasic function except POKE—that ishow you would put it there. That makesit ideal for storing machine code or data

you want to pass between two pro-grams, so that i t is not lost when youexecute normally-destructive c o m -mands like LOAD or NEW. On a 1KZX-81, 16388/9 have the values 163880 16389 68.

Using the formula from chapter 28 ofthe ZX-81 manual, 0 + 256 x 68 is17408. That is the normal address o fRAMTOP in a 1K ZX-8 I I f you have aRAM pack plugged-in and wish to see i fa program you have would fi t into 1K,it may be tested by POKEing the fore-going values into RAMTOP, then en-tering the command P R IN T U SR1040. The machine will behave like a

59

§cursor to be highlighted in inverse videosuch as word processors:LET AS = C H R S ( PEEK ( PEEK16398 + 256 x PEEK 16399))

IF AS > " A " AN D AS <then print at Y, X; CHRS (CODE AS+ 128)

The statement P R I N T A T Y , X ;moves the cursor without printing.• 1640011 VARS. This pair of systemvariables enables you to find the addressof the start o f the variables area i f youwant t o g o PEEKing o r PO KEingaround, or the end of the display fi le i fyou want to work backwards to POKEcharacters on to the bottom two lines ofthe display which cannot normally bePRINTed upon.• 1640415 E-L INE. Contains the ad-dress o f the end o f the variables area.We can examine it to give a rough ideaof how much memory we have used,including system variables, program,display and variables:PRINT PEEK 16404 + 256 x PEEK16405-16384• 16412/3 STKEND. Contains the ad-dress o f the top end o f the calculator,immediately below spare memory. Usedin conjunction with ERR-SP 16386/7,we can obtain an approximate idea o fhow much memory we have lef t i nwhich t o w o r k . P R I N T ( P E E KI6386—PEEK 16412) + 256 x (PEEK16387—PEEK 16413) The figure is inbytes.16417 not used. This system variableis not used but is available to the user;you could use it to store information inthe form o f an integer from 0 to 255.That would be saved on tape when theprogram is saved.• 16418 DF SZ . Define screen size, orthe number of lines in the lower part ofthe screen. I f you POKE a value of 1 or0 into this system variable you can uselines 22 and 23, so that PR I N T A T22,0; and PR I N T A T 23,0; becomeacceptable statements. I f using INPUTor SCROLL, you should restore theoriginal value, normally 2, or you maycause a crash. Conversely, i f you areshort of memory and using a SCROLL-ing display, you can make scrolling startfrom further up the screen by POKEinga value greater than 2 into 16318, aBasic part screen scroll.• 16419/20 S-TOP. This contains thenumber o f the top line in automaticlistings. Automatic lis tings are thoseproduced when you press NEWLINE.It can be annoying when you are tryingto work on one part of a lis ting and thecomputer insists on displaying a differ-ent part.

To place any line number you want,

say line X, at the top of auto listings youmust fi rs t move the cursor to a linenumber greater than the one you wantat the top. Then enter the commands:POKE 16419,X—INT(X/256) x 256POKE 16420,INT(X/256)0,16425/6 NXT EIN . The address o fthe start o f the next program line. Youcould use i t to run machine code in aREM statement anywhere in the pro-gram, e.g.:100 L ET A U S R (PEEK 16425 +256 x PEEK 16426 + 5)101 R EM m a c h i n e code

Or you could use N XT L IN to securi-ty-lock lines into programs to point outthat, for example, you hold copyright toa program. I t should not be possible toedit out those lines easily. The easiestway o f doing so is to change the linenumber t o 0, which cannot easily beremoved. As an example, we will lockline 100 in the following program:

'It may be necessary to determine whetherthere is room for a word on the current line ori f it is necessary to move to a new line toprevent the word being chopped in two'

I R EM any program2 REM 1982

90 LET A P E E K 16425 + 256 xPEEK 16426100 REM (C) D ILWYN JONES 1982110 POKE A,0120 POKE A + 1,0130 STOP

Now edit out the additional lines 90,110, 120, 130. You should be left with:1 R EM any program2 REM 19820 RAM (C) DILVVYN JONES 1982

Note that the lines are not necessarilyin the correct order but that w i l l notaffect lis tings o r the running o f theprogram.• 16436/7 F rames . T his is a framecounter which counts the frames o f apicture sent to a TV set. It is increment-ed 50 times a second and can be used fortiming with a range of about I I minutesbefore repeating. T o set the timer in-itially we use:POKE 16437,255POKE 16436,255

They may be entered as direct com-mands or used as program statements,although o f more use within programsbecause o f the limited t iming range.The values of the frame counter start at65535 and count down to 32768, be-cause bit 15 is normally 1. Once it hasbeen re-set, its value is read like this to

give a value in seconds: LET T IME =(65535—PEEK 1 6 4 3 6 - 2 5 6 * P E E K16437)/50

The variable T I M E then containsthe time elapsed in seconds since theframe counter was re-set.

Remember that PAU SE uses t heframe counter, so you cannot be timingand use PAUSE, too. I f you want adelay while using the frame counter fortiming, use a FOR/NEXT loop of about1 t o 6 0 f o r every second o f delay.Remember also that b it 15 should al-ways be I when timing. I f both bytes ofthe frame counter reach zero, the pro-gram will crash.• 16441/2 S- PO SN. Af ter you usePRINT at Y,X; where Y and X areprint co-ordinates:PEEK 16441 would be 33—XPEEK 16442 would be 24— Y

16441 contains information as to thel'R INT column number but i t is not

very easy to use. I f X is 0—the PRINTposition is somewhere on the left-handside o f the screen—the value o f 16441starts at 33 and decrements by I f o revery column across the screen. T hevalue o f 16442 starts a t 2 4 i f thePRINT position is at the top o f thescreen and decrements by one for everyline moved down the screen; 16441 maybe used in programs which handle text.

It may be necessary t o determinewhether there is room for a word on thecurrent line or i f it is necessary to moveto a new line to prevent the word beingchopped in two. Suppose the word to beprinted was A$. T o prevent AS beingchopped in half you could use:IF P E E K 16441 < L E N AS + 1T HEN PRINTalways assuming, o f course, that theprevious PRINT item ended in a semi-colon or comma. It may help to think of16441 as the number of characters + 1which can still be printed on this line ofthe screen.• 16444 to 16476 printer buffer. I fthe printer is not used, may be used tostore information i f you have nowhereelse to put it.4,16507/8 n o t used. These two un-used system variables can be used bythe programmer t o s tore integers i fneeded. They are saved on tape alongwith the program.


1

Inside Sinclair

Sinclair Research has always been muchmore than Sir Clive Sinclair. In our

occasional series we have been behind thescenes to find the people who help to make

the company successful.

1984 I S I NCLAI R USER Annual 1984

I h a t i 11:-

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PEEPING from behind rows o f ter-raced houses near the centre o f Cam-bridge is the Sinclair Research ultra-modern new computer centre.

The architect, Cristoph Gri tlet, pic-turedle ft, o f Lyster, Gri tlet and Har-ding, i s sa id t o have combinedCambridge traditions with major inno-vations in architectural design, interiorfurnishing and environmental controlsystems.

One o f the ducts for the system canbe seen in the picture on the immediateleft above the office which overlooks theentrance hall. The hall is dominated bythe sculpture, shown far left, DoubkTorso II by Helaine Blumenfeld.

Stainless Sinclair

•

b 3

Former school chum nowlooks after the money

In the management changes at Sinclair Research last year, Bil lMatthews became financial director. He talks to Claudia Cooke

B I L L MATTHEWS sits i n hisoffice and smiles at the recollec-tion o f his old school chum, Sir

Clive Sinclair, tinkering w i th radioswhile the other boys listened to them.

"He was innovative even at that age,you know. H e was always tinkeringwith something and he made his firstmatchbox-sized radio while we werestill at school.

"We lived very near each other inGuildford and I remember going to hishouse for enthusiastic demonstrationsof his latest plans. I think he was verymuch an individual character and didnot fi t into the standard schoolboy im-age at all".

A great deal has happened to bothmen since those early days a t S tGeorge's School, Weybridge, Surrey.Now, once again, they are together, BillMatthews having joined Sinclair Re-search as finance director last Septem-ber.

"I was working in Toronto last yearand Clive had to go there for a Mensa

conference. We had lunch and he askedme i f I was interested in this job. Ithought what the hell, why not? Here Iam, thoroughly enjoying i t".

The tw o men, i n fact, workedtogether previously, bu t i n the veryearly days o f Sinclair Radionics. " Ithink I kept his cash book or somethingwhen he was busy packing-up and sell-ing little bits by mail order. It seems along time ago".

Matthews, now 43 and married withfour children, went straight from schoolto read economics and business admin-istration a t Sheffield University. H efollowed that with training at a firm ofaccountants in London, qualifying as achartered accountant in 1963.

The first five years of his career werespent in public accounting in Turkeyand Italy. " I t was great to be able totravel and, having been released fromall that studying, I d id a reasonableamount o f work but certainly nothingyou could call strenuous".

Then followed marriage and the offer

of a job with ICI as a group accountant.He spent four years there and sti l lconsiders it one of the best-run compan-ies for which he has worked.

He moved on to become financialcontroller for Sony U.K. for two years

'He asked me i f I wasinterested in this job.I thought what the

hell, why not?

and was involved in setting-up the com-pany's successful television factory i nWales. Emigration to Canada was thenext step, working for management con-sultants Price Waterhouse. H i s mostrecent job, in Houston, Texas, was asexecutive vice-president o f a companywith clients from the oil and gas indus-tries.

11 SINCLAIR USER Annual 1984 !

A varied career but one which hasalways involved him in the use of com-puters, particularly for management in-formation. The finance department atSinclair Research is now in the processof computerising i ts system wi th anICL 25. Matthews expects i t to be o fconsiderable help in financial reportingand control.

One o f his first tasks at Sinclair wasto place 10 percent o f the companyshares with institutional investors, anoffer which was well-subscribed, H esays:

"We see ourselves getting a StockExchange quotation in two years. I t isstill our intention to keep the companysmall in terms of the number of peopleemployed; that concept has not disap-peared.

"Sales have grown substantially andwe have reached a size where we couldissue shares and get a public quotation_It wi l l be our coming o f age, i f youlike".

Matthews sees one o f his tasks asensuring that Sinclair has sufficient re-sources to continue to grow rapidly and

'We have to becareful because the

life expectancy of ourproduct is fairly

short'

ensuring that those resources are gener-ated from within the company — fromits profits. No easy task, he admits.

"Coming fro m a financial back-ground, you find all companies have agreat deal in common. The exceptionalthing here is the sheer speed with whichwe are growing and the dynamism o four research activities,

"It can be a problem to find theresources to cover all that development.It creates i ts own problems and putsexceptional pressure on everyone whoworks here but i t also creates a muchmore optimistic attitude among thestaff. We tend to pay better than thenormal market rates to get good peopleand it is a marvellous team".

Matthews says the company philos-ophy will always be to design productswhich are inexpensive and produced inlarge volume, thus making them widely-available.

"I think the Sinclair computers aremarvellous little machines. We are justseeing the beginning of a revolution inthe use o f computers. The first stage

was to make them so inexpensive thatanyone could use them and Clive hascertainly done that.

"We have to be careful because thelife expectancy o f our product is fairlyshort. You can be fairly sure other firmswill catch-up rapidly. We have to makethe best use o f that technical lead andexploit i t fu l ly, to the best possibleadvantage. We cannot afford to sit still.In three years I do not suppose the ZX-81 will be marketed. We are not makingpyjamas for Marks and Spencer afterall; that kind of thing you can probablygo on selling for about 200 years.

"We must have a stream of new andinnovative products all the time and wemust remain inventive".

Listening to those exacting standardsis tiring but they are the standardswhich have taken Sinclair to the top soquickly and Matthews has absorbedthem with equal speed. Approximatelyhalf the staff o f Sinclair Research i sinvolved in research and developmentand Matthews intends to concentratesubstantial resources fo r i ts continu-ation, buying new premises and rational-ising existing ones.

With Sinclair products tending to bemarket firsts, Matthews admits there isoften a tendency to under-estimate theproduct. "When sales are restrictedthey are restricted b y the ability toproduce rather than lack of demand forthe product but one has to be cautiousto a certain extent," he says.

"You are making a commitment tothe subcontractor, so you have to becareful not to over-estimate the demand.Then the subcontractor has to buy com-ponents and perhaps hire people_ Soyou hzve to be as realistic as you possi-bly can.

"Producing new concepts means agreater risk element and greater flexibil-ity i n financial control. You have tokeep re-assessing the situation in finan-cial terms and try to predict what willhappen".

Because the Sinclair market is largelydomestic i t is by nature more volatilethan selling to big industry. This isanother factor Matthews has to takeinto consideration. With all that on hismind, Matthews, who displays a Casiocalculator on his desk, has not yet hadmuch free time to experiment with theSinclair products.

His eldest 1-year-old son has com-pensated for that. He has two Spec-trums at home and, his father says,spends most of Es time sitting solidly infront of them, lost to the world.

He has has two sisters, aged 12 and13, and a five-year-old brother, bu t

none is yet showing the same enthusi-asm.

Matthews likes to keep fit in his sparetime and when I visited him was keenlyawaiting the Sinclair half-marathon duein Cambridge on July 17. No newcomerto running, he participated in last year'sBoston marathon. Nevertheless he wastaking the Cambridge event seriously.So, no doubt, was one o f his fellowrunners, S i r C l i ve Sinclair. Th e i rspeed, it seems, is not confined to work,nor their competitive spirit.

Matthews is reluctant to predict howlong he will stay with Sinclair but says:"The chances are it will be a long time.I am really enjoying i t so far and withthe effects o f recession hitting so manycompanies, i t is fine to work for one assuccessful as this.

"We have built a very big turnoverand we have the financial resources toexpand into the future. That all givesthe company a great deal o f strength".

As part o f the Sinclair management

BI LL M A I-T H E : W S

'Sinclair compuieri are manellousl i t k muchincs'

team, Matthews attends the monthlymeetings of the board, together with SirClive, Nigel Searle the production di-rector, and two research directors.

At the moment the board doubles as amanagement committee which has en-abled Matthews to look at every aspectof the company within a short space oftime. He likes what he has seen and isfull o f praise fo r everyone, from thegenius of Sir Clive through the dedica-tion of the rest o f the stall down to theexcellent quality o f the company can-teen.

In short, he appears to have beenconverted and he speaks as i f he hasbeen with the company for years. StGeorge's, Weybridge should be proud.

SINCLUR USER AFtnual 19S4 65

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1490

We meet the people who deal with your queries and complaints.A behind-the-scenes look at the Sinclair mailing house

The go-betweensINCLAIR RESEARCH com-puters are now in a class of theirown in the home computer market,which the company has done

most to create. Despite i ts policy o fselling many o f its products by mailorder, however, few of its customers havehad direct contact with the company.

The reason is one o f its other well-known policies — sub-contracting. Asmuch as possible o f the business o fmaking and selling Sinclair products isdelegated to outside companies, allowingSinclair Research to have a very smallstaff, slightly more than 50 a t themoment.

Most people who manage to obtaintheir machines and software without toomuch trouble find that the nearest theyget to Sinclair Research is a companywhich works from small offices and awarehouse on a featureless industrialestate in the Surrey town of Camberley.

The offices are those of GSI U.K., theaddress and telephone number of whichappear in Sinclair advertisements and towhich the mail order coupons are sent. Itis GS! which has the task ofbeing the firstline of complaint and query, answeringthe growing number o f Sinclair usersthroughout the country. It is also the GSIswitchboard which plays music to soothethe patient person waiting for a query tobe answered.

GS! U.K. is the British subsidiary of aFrench company which has bui l t areputation as a supplier o f marketingservices to the motor trade. It maintains amailing list for a large number of motordealers which can be used when aparticular group o f people need to becontacted. GS I also looks after thedespatch of the information.

NI GEL BROWNIn charge or the Sinclair accou t

Wirtit s assotiates, GSI claims to bethe biggest computer bureau fo r themotor trade i n Europe. I ts ultimateparent is CIT-Alcatel, a division of CIT,the power generating company which isthe private equivalent o f Britain'sCentral Electricity Generating Board.

The expertise for large mailings with acertain amount of mail order distributionled to the company being consideredwhen Sinclair was looking f o r adistributor.

"We had a good deal ofexperience withkeeping names and addresses on file andmailing, so it was natural to start doingsomething like the Sinclair work," saysNigel Brown, product manager at GSI,who is in charge of the Sinclair account.

"We started working with Sinclair inOctober, 1980 when the ZX-80 was stillbeing produced. Before that Sinclair hadlooked after the distribution 4nd weneeded only four people at that stage."

At that time the company was known asJaserve, changing to GSI when i t wastaken over in April, 1981,

"WIth the launch o f the ZX-8 I i nMarch, 1991 the work became muchbigger, which was when I became theaccount manager, "Brown adds.

N 3W there are 58 people workingexclusively on the Sinclair contract,whith has grown to become a substantial

(18 S I N C L A I R USER Annual 1984

part of the British company's turnover.Every one of the Sinclair products, the

range o f which now includes tw ocomputers w i t h different versions forthe different television and powersystems throughout the world aprinter, printer paper and a growingamount o f software for all uses, passesthrough Camberley on its way to thecorners of the world.

Each day tw o large, articulatedcontainer lorries make the long journeyfrom Dundee to Surrey with the latestbatch o f Spectrums, ZX - 8 Is andprinters. Another slightly smaller lorrytakes more products from the otherSinclair suppliers.

They all go into the large, highly-secure GSI warehouse but rarely stay forlong. The items to be sent to distributorsin export markets are sent to anotherwarehouse, leaving GSI to deal with thedistribution i n Bri ta in and thosecountries which have no agents.

Many items go almost immediately tothe growing number o f retailers nowstocking the Spectrum and thc ZX-81,while the rest go in batches of 50 to themail order customers.

When the mail order system is runningsmoothly there is a clear number ofstagesin the processing o f each order. Everymorning the post i s sorted in to thcqueries and the orders, which are thenfurther divided, depending on the goodsrequired and the method of payment.

Cheques and cash are paid into aspecial holding account, where themoney stays until the order has beensatisfied; then i t is transferred to theSinclair sales account. Credit cards arenot charged until the order has beenfulfilled.

The orders are then entered on thecomputer and all the data stored on tape.When the goods are available to be sent,address labels are printed and anotherSpectrum or box of cassettes is ready forthe post.

At the moment it is possible for GSI tosay which stage a particular order hasreached but not where i t is within thatstage. That resulted in many complaintsduring the Spectrum delay difficultieslast year. Although an anxious customercould be told that their order had beenreceived b u t was no t about t o bedespatched, they could not find the placeof their order in the queue. A new systemis being installed which will allow thestate of orders to be seen at a glance.

Brown adds that at the height o f theproblems i t was difficult to be morespecific, so that customers were notmisled.

SINCLAIR USL7 Annual 1984

"We could give only general replies asthe situation was always changing, so wethought i t better not to give a specificanswer which might then have to bealtered," he says.

"Sinclair made a policy that everyoneshould be kept as informed about theposition as possible and I think we wereable to achieve that."

Most o f the queries and complaintswere by telephone, a customer servicewhich has grown rapidly along with therest of the Sinclair business. In October,1980 there were only two lines. Theyhave grown in stages, first to four, theneight, then 18, and last summer another10 were added.

"In the early days on our two lines wewere receiving about 100 calls a day.When the ZX-8I was launched thatexploded to 1,000 a day. Now I think weprobably have a capacity of about 2,000 aday," Brown says.

The calls deal with a vast number ofsubjects. Apart from complaints aboutThe warehouse filled with Sinclair products ready for despatch

non-delivery or faulty machines, manyusers need advice on particular aspects ofusing the machines. Some things, such assaving and loading difficulties, arc thesubjects of regular queries and there arealmost 40 leaflets giving advice whichcan be sent.

For the more complicated queries therearc three more technically-mindedpeople available who attempt to find ananswer.

Whatever the difficulty most o f thecallers are still polite. Even when thedelays were at their worst last year, no-one became abusive when makingcomplaints.

The GSI position as the public face ofSinclair Research will be reduced as theretail sales of Sinclair products increases.It is likely to remain the first place peoplewill contact wi th their problems andcomplaints and will remain an importantpart of a string of companies involved inthe production and selling o f Britain'smost popular computers.

69

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.1-:OMNI CALC 148K Spectrum)The best Spectrum spreadsheetyou can buy. Writ ten in machinecode to be faster, to give youmore s pac e f o r data, and t oal low mo r e f ea t u res t o b einc luded. i t i s g u a r a n t e e duncrashable* 99 columns or 250 rows.* Fully prompted input.* Extensive repeat facilit ies.* S u p p o r t s A L L S p e c t r u m

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- ,INCLAIR USER Annual 1984

Futurology

A speech by Sir Clive Sinclair to the BritishMensa Society on the expectation o f a newGolden Era being caused by the growth of

computer use began a series on what peoplebelieve will be the result of the increase in

computer ownership.


Computers bringnew Golden AgeSir Clive Sinclair sees a bright future

As WELL as being head of Sinclair

Research, Si r Clive Sinclair ischairman o f British Mensa, an

exclusive club whose members have !Qswhich reach the genius level.

In a speech at the Mensa GoldenAges symposium a t Cambridge, S i rClive outlined his ideas for the future,not o f his range of personal computersbut of the Western civilised world. Hesaid: " I intend arguing that the mostGolden Age of man's history may welllie before us, i f we can only move in theright direction."

The new age would need to be trig-gered by an event which wi l l startlesociety. Th e trigger, h e explained,would be something similar to the in-vention of writing or moving type. Hesaid: "Both o f those developments re-duced the cost of data transmission by afactor of 100."

He saw leisure, or periods of time notoccupied by formal work, as an oppor-

tunity to broaden the mind. I I the trig-ger occurs at the proper time and theGolden Age arrives "the body of menarises which can turn i ts attention tomatters other than necessities. Thuswealthy patrons produce th e greatflowerings of arts which are a feature ofthe Golden Ages.

"Equally, the Golden Ages are oftenmarked by one great individual, a typeof philosopher-prince, e.g., Pericles,Augustus, Lorenzo de Medici, Eliza-beth I and Louis XIV."

In business operations, S i r Cliveseems to regard the personal approachbest — one man at the head o f a com-pany. He has stressed that approachmany times through Sinclair Research,so that now he is as famous as hismachines, whereas other manufacturersremain masked by their company exter-iors.

During his speech he referred hisideas to the present day. He saw the

Golden Age as being very close. Someof the features which marked the Gold-en Ages of the past could be identifiedwithin our time. That could place us onthe threshold of a new Golden Age, Todemonstrate it, Sir Clive returned to theidea of a trigger.

"Is there a trigger? It so happens thatanother hundred-fold reduction in thecost o f data publication and transmis-sion is about to occur. A single 12in.diameter optical disc, being developedfor use w i th T V can, remarkablyenough, contain the information o f10,000 books and that disc will cost notmuch more than a few books—almost,in fact, a thousand-fold reduction incosts,"

The reduction in costs and the inno-vations in mass marketing are comparedto what Sir Clive calls "the potential ofthe individual". Unti l now, society hasaccepted that people will work togetherin large groups. People work in largecompanies, they commute into townsand cities every working day. Thatmassing o f the working population isthe motive force behind the presentstate of the economy.

Sir Clive said: "We have for sometime been passing through a great in-dustrial age in which the economic basisof society has demanded the bringingtogether o f people in great numbers,many thousands per factory, many mil-lions per city. I believe that our moveaway from this type of organisation willrestore the potential of the individual."

Individual human potential is some-thing he seems largely to favour. WhileSinclair Research is a company, likemany others, where everyone pul lstogether, i t is sti l l mostly a one-manoperation. Si r Clive is the man whodefines what he wants and lays-out thetimetable for its development.

That style o f operation has so farproved successful, first with the ZX-80and ZX-81 and then with the Spectrum.The hundreds of firms which give sup-port to Sinclair microcomputers wouldalso seem to prove his point to becorrect.

He sees the new Golden Age as beinga time of the mind, with less stress puton the body and building culture ratherthan labouring. He feels that anotherGolden Age requirement is an abundantsupply o f patrons, people who can ap-preciate, as well as create, art.

"We have a well-educated popu-lation, a society which reveres the arts,and have become a world centre formusic and for the written word."

The reason fo r the swing towards


cultural pursuits is marked wi th thestigma of a current curse on society.

Sir Clive said: "We have potentialartists, partly for the sad reason that wehave three million unemployed; this isnot a passing phase o f recession but atrend which will last until the end of thecentury, during which I expect themanufacturing industry to shed a fur-ther seven mill ion jobs and fo r theproportion employed in manufacturingto decline from some 42 percent o f thepopulation to less than 10 percent. Thiswill occur as automated systems arenow radically cheaper than manualcosts."

The resulting factors o f unemploy-ment due to technological innovationand automation wi l l leave the popu-lation with a great deal o f spare time i fpresent trends continue. I f the numberof unemployed rises to more than 90percent it may be necessary to re-definethe term altogether.

"Many, if not all, of today's youngpeople will always work for small or-ganisations and indeed must foundthem. We must encourage people tofollow this route i f we are to createfuture employment—whether in hightechnology, in a revival of a class, or inservice industries."

Sir Clive foresees a new "creativeendeavour". People are experiencingnew technology, seeing what i t can dofor them. It can relieve them of manualtasks so that they can use their mindsmore fully.

Young people were just beginning tolearn about new technology. Accordingto Sir Clive, the learning process wouldbe only the beginning.

Learning about ne w technologythrough machines such as the ZX-81and the Spectrum which, because of lowprices, were within the reach of' nearlyeverybody, was the beginning o f aprocess which may lead to what hebelieves is a new Golden Age.

"Because w e n o longer need t odevote the bulk o f our time to theproduction o f objects, I can see theplateau o f a Golden Age before us.Certainly we may need inspiration andleadership, great building, a bridge overrather than a tunnel under the Channel.

"Early in the next century we willhave made intelligent machines endingfor all time the pattern of drudgery. Itmay be that Western civilisation, seededin seventh-century Ireland, is only justabout to flower."

To some, his ideas may seem likescience fiction but some cynics said thata machine like the Spectrum was notpossible only a short time previously.


MORE THAN 2,000 years ago,

Aristotle made the commentthat we work to have leisure.

For him, leisure was a reality, since allthe toiling and much o f the producingwas done by human slaves. For mostother people then, and since, work hasbeen the essential part of human life aspeople have struggled just to survive.leisure has been, at the best, a residualand generally meagre amount of time.

Today, because of the introduction ofcomputers and microprocessors, we aredeveloping a new type o f slave, in theform o f electronic robots o f all kinds.That represents a major change in ourlives, which will give new meanings andnew dimensions to work and leisure.

Perhaps, most of all, new technologymeans a growth in the amount of leisuretime. That is not an unmixed blessing.Although people will need to work less,they wi l l also have to learn how todevelop their lives in the v,:tay Aristotlemeant when he talked about leisure.

In some measure, we have alreadyentered an age o f leisure, with a mile-stone at the beginning o f the 1970swhen the amount o f time the averagefull-time worker spent at work during ayear fel l below the amount o f timeavailable for leisure.

Since then, a typical worker's leisuretime has increased by some seven per-cent to more than 2,500 hours a year,while the number of working hours hasfallen to 1,950, including travel to andfrom work.

Less positively, we now have thelarge amount o f enforced and ma!-distributed free time represented b ymore than three million unemployed.

With the expansion of free time andthe need to find ways of occupying it ina satisfying manner, the development ofthe microcomputer, with its time-inten-sive quality in use, seems to be particu-larly fortu i tous. Certa in ly h o m ecomputers will become increasingly im-portant in people's lives but we need tobe realistic about just how fast privateownership o f computers wi l l developand a lso about exactly h o w th emachines will be used.

Without becoming involved t o o

Less work, morecomputer playFuture leisure activities surveyed

deeply in the psychology o f leisure, i thelps when thinking o f the possibleroles microcomputers might play in ourleisure lives to consider for what we useour leisure. I t is possible to identifythree functions of leisure which formsomething of a hierarchy—rest and re-cuperation from work, entertainmentand the relief of boredom and, finally,personal and social development.

In the era of leisure we are enteringthe function of leisure as rest and recu-peration declines in importance as theamount of work lessens and the effortinvolved decreases. That puts the em-phasis in leisure time use on the twoother functions of entertainment andself-development, both areas where weexpect to see the microcomputer play anincreasingly large part.

An obvious role microcomputers playin the area of entertainment is of beingvirtually an infinite compendium o fgames. They can provide an unendingsource of pastimes for those who wish tooccupy their leisure in this way.

It could be argued that people coulduse a chess set or a pack of cards insteadof a microcomputer for those simpleractivities. The answer lies probably inthe basic attraction o f using new tech-nology, as well as in the perpetual self-challenging quality of computer gamesand the wide variety of pastimes avail-able from the one machine.

Once attracted to the computer, thegames player is likely to look progres-sively for more complex games to playand may eventually take the step to-wards developing improved or originalprograms. At that stage, the computermoves from being a source of entertain-ment to potentially a very time-consum-ing hobby, offering great opportunitiesfor individual learning and develop-ment.

Many people have turned to micro-computers without any particular em-phasis on games playing. Either way,and whether interest lies primarily inthe hardware or software, all computerhobbyists have found a leisure occupa-tion of absorbing interest. In the future,when there may be considerably morefree time but possibly not so much extra

75

76

money to spend on leisure, the time-absorbing nature of computing is a valu-able characteristic.

In addition, as members of computergroups know, there can be a strongsocial element in the hobby, producingnew friendships as we ll as a usefulexchange of experience and ideas.

There are other aspects o f what wehave termed self-development in whichwe believe the microcomputer poten-tially has an important leisure role toplay. By self-development, we mean thewhole process of learning and enlargingone's mental and physical capabilitieswith the aim o f leading a fuller andricher life.

Naturally the microcomputer cannottake the place o f weightlifting, joggingor other sports in improv ing physicalcapabilities but, as a provider of aid toeducational and cultural development,it could have a v ital part to play. Pre-viously i t was often people o f leisurewho went t o university t o enjoy thebenefit o f learning, often for its ownsake; in the future, the micro will helpto take learning to the homes of all whowant it.

How quick ly w i l l a l l this happen?How soon can we expect to see a microin every home, as some commentatorsenvisage? How many people w i l l , i npractice, be encouraged to use this newgadget to educate themselves and theirfamilies?

Our forecasts appear to be somewhatmore conservative than those o f manyothers. We expect that, by the end o fthe decade, something like one-fifth o fall households, s ome f o u r m i l l i o nhomes, w i l l have a mic ro bought forpersonal use; others, as now, will have

machines used both for the business andfamily.

Behind that view lies the assumptionthat microcomputer prices w il l fall toaround one-third o f what they are atpresent. An even sharper fall in priceobviously would boost demand. We donot think a very high proportion of the33 percent o f households where thehead of the household is over 60 yearsof age w i l l b e buy ing a microcom-puter, even i f it costs only £10.

Despite the growing amount o f freetime, the majority of people are likely tobe fair ly s low t o recognise what themicrocomputer can offer them. T h eattraction o f games-playing is obviousbut for many people the idea of leisureas a period of education is a novel oneand, dur ing the 1980s, mos t o f thedemand for educational use is likely tobe stimulated by children's needs.

It w i l l probably not b e un t i l t he1990s, when the first generation of chil-dren to whom computers are a part o feveryday life become adults, that a realwidespread educational use o f homecomputers will develop.

Since many people, not least the un-employed, will be having a leisure prob-lem well before then, w e hope thatthose already keen on computing w il ldo a l l they can t o t r y t o make ourforecasts seem too pessimistic.

Aristotle probably would have en-joyed the challenge of microcomputingbut even he might have needed someencouragement to take the first steps inthis new leisure direction.• B i l l Mar t in and Sandra Mason o fLeisure Consultants, Sudbury, Suffolkhave published a report on leisure in the1990s.

MicrojunkiesChris Reynolds

MANY YOUNGSTERS have

home computers becausethey, or their parents, feel

that owning such a computer will helpthem in their careers. As a universityLecturer responsible for training futurecomputer professionals, I hav e m ydoubts. Let me explain.

In the last 30 years the uses of com-puters as part o f practical working in-formation systems have mushroomed.For most o f that time there has been adesperate shortage o f suitably-exper-ienced staff. Salaries rocketed as com-panies bid to obtain employees with thegreatest length of experience, apparent-ly regardless of quality. The whole wassurrounded with the prestige of being atthe forefront o f modern technology, atleast in the eyes of one's neighbours.

Much of the gloss has now been shed.There is, o f course, s till a shortage o fgood computer professionals bu t theincompetent now find it almost imposs-ible to c limb on the bandwagon, andsalaries are no longer so wildly out o fline w ith other occupations. O ne nolonger hears people boasting that theyknow someone who knows someonewho works with computers. I n fact, itseems likely that in five years having acomputer in the house will be socially assignificant as is owning a digital watchtoday. When acne-embarrassed school-boys with home computers are ten-a-penny the simple ability to program willhave no value in the job market.

Those changes w i l l have a majoreffect on the structure of the computerprofession. The need for highly-skilledpeople to work on research and develop-ment projects in the computer industrywill continue. The majority o f existingprofessionals work for companies whichuse computers as tools to help the com-pany business and it is in that area thatthe biggest changes will take place. Thepressure w il l be for more fl exible andeasier-to-use systems with the minimumof fuss.

A prime requirement will be for staffable to communicate with other people,verbally and in writing, with the mini-mum of jargon. Knowledge of manage-ment, economics and psychology, and

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the design o f systems are next on thelist. A good understanding o f what acomputer can reasonably be expected todo is of far greater importance than theability to PEEK and POKE on a par-ticular make of microcomputer.

Universities already have moved inthat direction and introduced courseswhich anticipate that future need. Forinstance, Brunel University has a Sys-tems and Information Managementcourse which has been running for fiveyears and which attracted 28 good stu-dents this year, compared to 22 on itsmore conventional course. Because it isfelt that breadth o f experience is im-portant, students who do not have Alevels in computer science and math-ematics are preferred to those who havealready specialised narrowly w i t hdouble mathematics and computer sci-ence.

Many o f the leading 2 Ist centurycomputer professionals are n o w a tschool and in the light o f the foregoingcomments, it is useful to speculate whatthey are doing now. We can be certainthat they will be well-acquainted withmodern electronics technology. Digitalwatches and pocket calculators will betaken for granted. Their parents wil lhave television sets with teletext and avariety of electronic games. As soon asthey are old enough they will use auto-banks and credit cards to buy thingssuch as electronic organs. Even i f theynever saw a general-purpose computerthey would take for granted keys to bepressed, video displays, and automaticinformation processing.

While at school they will almost cer-tainly have been given a computer ap-preciation course and may have hadcomputer-aided instruction. Most wi l lhave taken 0 and A level computerscience. That will not be because this isnecessary for their careers hut because

'The pressure will beon for more flexible

and easier-to-usesystems'

the education system encourages earlyspecialisation.

Socially, most o f them will be goodmixers. They are therefore likely to befound in the Boy Scouts, the schoolband or the local cricket team.

One thing not mentioned is owner-ship of a home computer. The reason isthat the evidence at Brunel suggests

that in many cases a private micro canhave a n adverse effect o n studentstudies and sometimes on employmentprospects.

There are a number of reasons. Thefirst is that to understand and use alanguage well, vou have to be able tothink in that language, be i t French,Arabic, Pascal or Cobol. Students whohave written a large number o f pro-grams in a single language, often on asingle machine, have difficulty in trans-ferring to other languages.

Gerald Weinberg, in his book ThePsychology o f Computer Programming,showed how easy i t was to guess astudent's former language by the stylis-tic errors he makes in learning a newlanguage. Ten years later the problem ismuch the same. Most novice studentslearn rapidly the essentials o f modern

purer is bought by enthusiastic parentsto encourage him in what is certain tobe a wonderful career in this marvelloustechnology. He is delighted to be al-lowed to spend many hours every even-ing enjoying himself in the privacy o fhis room. Socially, he finds he can boastabout his wonderful programs whichlook most impressive, w i th flashingscreens and perhaps even sound effects.

Because o f all this praise and theabsence o f anyone who can assess thequality o f his work properly, he soonbecomes convinced that he is a com-puter genius and spends even more timeat the keyboard. He has become a codejunkie who craves for his two-hours-a-day session at the keyboard.

In fact, the idea of code junkies is notnew. In the last decade we have hadseveral who have become addicted to

'The big danger seems to be the bright butsocially-gauche adolescent. H e fi nds t h eschool computer more fr iendly than h i sschool-mates and develops an interest rapidly'

programming concepts, such as block.structuring and recursion

Students who have extensive experi-ence in old-fashioned languages whichlack those features often insist on usingmore powerful high-level languages as i fthe newer features did not exist. That isapparently because they find it easier towrite longer, inelegant programs thanto learn something new.

The second problem is that writingprograms and playing games on a homecomputer i s most entertaining. Th eability to use a home computer is, how-ever, o f little relevance to any but themost junior jobs in the computer field.Most adults would discourage a childfrom wanting to become a televisionnews reader simply because he had builta crystal radio at the age o f eleven.Unfortunately computers are so new,and so mysterious to many adults, thatmost teachers and parents are not suffi-ciently knowledgeable to recognise afun hobby as just that and, as a result,they encourage children to attempt tofollow a career path for which they maybe almost totally unsuited.

The big danger seems to be thebright but socially-gauche adolescent.He finds the school computer morefriendly than his school-mates and de-velops an interest rapidly. A home corn-

the university computer. From experi-ence we know that almost a l l suchstudents fail the course. They prove tobe almost unemployable because o ftheir inability t o get o n wel l w i thpeople, and because of a marked reluc-tance to work with, rather than playwith, computers.

In 1981, for the first time, we had theproblem o f new undergraduates whowere already code junkies before theyarrived. This year the number o f stu-dents who have home computers onarrival has more than doubled and it issuspected that many of them will proveto be junkies.

It has been said that home computersand computer games will help to keepthe future unemployed occupied in anenjoyable manner. That may well betrue in the long term, when society hasbecome adjusted to the new technology.In the short term there is a danger thatthe majority o f the unemployed whoplay such games wil l be code junkieswho caught the bug during a vulnerableperiod of adolescence.• D r Chris Reynolds is reader in com-puter science at Brunel University. Heorganises the computer science teaching forfirst-year mathematics computer sciencestudents. He also researches improved sys-tems for the man—computer interface.

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Hooked onarrogance

R Bird supports micro training

COMPUTING is much more

than programming. I t is con-cerned wi th the flexible use

and application of ideas. The ideas arestructured logically by means o f a lan-guage.

That is one of the reasons why manyof the conclusions of Dr Chris Reynoldsare incorrect. Although much o f whathe says is valid, the tone was prejudicedand negative_

All the problems o f vocational com-puter training were blamed on ownersof the home computer. The only slightcomment in favour of the powerful littlemachines appeared in the last paragraphbut even then they were dismissed aslittle more than games machines.

To condemn home microcomputerowners as potential code junkies—people with an addictive, perverse inter-est in computers—probably as failuresin academic life and as unemployable isa form of professional arrogance. Mostpeople who have an interest in comput-ing also have other interests.

It is the same arrogance which leadsmany people to claim exclusive rights tocomment o n particular branches o fknowledge, especially h o w thosebranches will develop in the future.

There are likely to be many problemsassociated with the future in areas suchas jobs or careers, leisure and education.None of those can be answered by anyone group, be they teachers, employers,lecturers or workers, claiming they havethe exclusive right to comment anddecision-making.

Neither should Reynolds be advocat-ing novice students in computing. Thatkind o f logic is rather like a professorFrench insisting on novice speakers—those who do not speak yet—if he is toproduce good speakers of French.

A teacher of a foreign language musttake account not only the students ownlanguage but also their developmentwithin that language.

If a student has had experience o f acomputer language i t is reasonable toexpect lecturers to take it into account.If specific languages cause problems,the lecturer must identify the problemand work out ways of overcoming them.

A lecturer should not advocate novicestudents; i t is no solution.

There is a clear and unfortunate ri ftbetween academics and non-academics,professionals and amateurs. Academicstend to be more concerned with protect-ing their access to knowledge ratherthan sharing it. Professionals seem to bemore concerned w i th keeping the i rright to knowledge rather than sharingit with amateurs.

Computing at a high level is for asmall number o f highly-qualified stu-dents and to suggest that the needs o fthose few are best served by denying thevast majority of home micro owners useof their leisure time activities is wrong.Academics appear to see things in oneof two ways. Either they are shut inivory towers researching and learning

'To condemn microowners as failures isa form of arrogance'

for pure knowledge, or are selling theirability to industry.

While I should not subscribe whollyto that view, I wish the apparent r i ftwhich contributes to i t did not exist.

With the introduction o f new tech-nology, people will find vast changes intheir life-style; work may never be thesame again. The concept o f five to 16education being sufficient may disap-pear: re-training several times may be-come the norm.

Most people with home microcom-puters would not suggest that theirwork with the computer would changethe world but they would not suggestthat those with computer PQX wereinferior to them or that all mainframework was necessarily superior.

The assumption common to manyvocation-minded computer studies/com-puter science lecturers, that their workwas important, simply because theytrain professional workers, is to misreadthe future. Before long, the day of thelarge "brain" will be over and the dayof the small, powerful computer wi l lbegin.

It is also clear that plain language oreven interactive voice computers are onthe way. When the man in the street cantalk to a computer and ask it questions,the mystery o f the languages probablywill disappear. Before that day arrives,however, we have the problem of manycomputer languages, but it is surely notbeyond the understanding o f profes-sionals in the computer field to struc-ture courses to take that fact in toaccount.

I notice that the Open University isto use a further form o f Basic in i tscourse Computing and Computers. Iam not condemning the intellectual lev-el o f the OU course but rather regret-ting the introduction o f yet anotherdialect.

Even with the limitation o f the newOUSBASIC, the Open University isshowing the way to other universitiesand polytechnics. The course has beendesigned to introduce beginners to skillsand techniques of computing. Most mi-cro owners would concede that theirprograms and computing would be im-proved for a better knowledge of struc-ture and logic, not to mention bettertechniques.

So, i n effect, what we have i s auniversity o r polytechnic departmentwith the skills and resources to teachboth the structure and techniques toimprove the standard o f home microowners. Alongside that pool of skill wehave a large number, perhaps some half-million at the moment, who would nodoubt welcome some of that skill beingtaught to them.

What better way of bridging the aca-demic, professional and non-academicamateur r i f t than bringing the twotogether?

That would create a new area of non-vocational studies for the institutes o fhigher education. As a spin-off, it wouldalso retain in those institutions some ofthe teaching jobs which are disappear-ing under the present retrenchment inthe higher education sector.

Clearly there would be advantages forthe students o f such courses. Theywould learn better techniques, theywould learn better ways o f using com-puters, they would learn other com-puter languages, not to compete withthe professionals but to use i n theirprivate studies.

The interaction between m i c roowners and the professionals, both atthe formal teaching and informal sociallevels, could only benefit both. Experi-ence from both sides could stimulatemore courses and lead to a leisure timeeducation industry.


1

Books

Publications of varying quality and quantityhave gone on sale during the year. John

Gilbert looks at the growing bookshelf andselects some typical examples of recent

developments.

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John Gilbert assesses publishing

THE COMPUTER publishing

market has developed so quicklythis year that publishers have

been desperate to lay their hands onanyone who knows something interest-ing about Sinclair computers, program-ming techniques, or who has someprograms they want to sell.

Some publishers have even askedteenagers to write books because insuffi-cient adult writers have been able to getto grips with the subject. That kind ofmove sets a precedent in the publishingindustry. N o other sector has eversought young writers with such vigour.If you can write and you have an above-average knowledge of computers thereis a good chance that a publisher willcontract you for at least one book. Theproblem is, and has always been, thatyoung writers know little about thepublishing industry and, through noconscious fault of the signing companyor the young author, writers do notobtain everything they should. Fortu-nately that does not happen often but itis a side-effect of the market growth andthe urgency with which publishers seek

Young authorsget opportunity

titles. The youngest writer of the yearmust be Patrick Bossert, author of thePenguin You Can Do The Cube. I nAugust, Penguin released one of its firstmicro-computer books by the 14-year-old. Unfortunately Micro Games waslittle more than a book of listings, astage though which many companiessuch as Shiva Publishing, Interface andMelbourne House passed earlier in theyear.

Penguin seems to have relied on Bos-sert's fame with the Rubik Cube andthat the puzzle and computers share thesame intellectual image in the publicmind. Just because Bossert can do thecube, however, does not make him anautomatic genius at computer program-ming.

The concepts for most of the pro-grams in his book existed earlier in theyear when all you could buy in terms ofthe Spectrum were books of listings.There is little that is new in the title — apity, since it is from Penguin, a publish-er renowned for its quality of output.

Books of listings were popular at thebeginning of the year when the ZX-81

had more of the limelight than theSpectrum. Authors such as Tim Hart-nell were having at least one book pub-lished a month. Most of those bookswere for the ZX-8 I, as most publishershad not yet advanced to the Spectrum,although i t was launched in April,1982.

Before the beginning of 1983 theonly publishers to try for somethingextra from the ZX-81 were Interface,Melbourne House and Shiva. All werestill small but it is a mark of theirinnovation which shows their successand expansion to date. Now all threehave a large share of the publishingmarket where Sinclair machines areconcerned.

By May all three companies had donesomething different for the Spectrummarket. Machine code programming forthe Spectrum was a subject whichwould sell books and the big threepublishers knew it.

Shiva produced Spectrum MachineCode, by Ian Stewart and Robin Jones.It was launched as part of the FriendlyMicro series and, although it did notcover the area in as much depth as someof the American books about the Z-80processor, i t provided a n excellentgrounding in machine and assemblylanguage. I t also added a humorouselement missing from many other bookswith 'bug' cartoons spread throughoutthe pages.

The other publisher renowned for itsstock of titles on machine code is Mel-bourne House. It has two machine codetitles which cover the ZX-8 I and Spec-trum. Both are similar in approach andit seems as if the Spectrum version wasedited from that of the ZX-8 I, withextra examples showing colour andsound added.

The other range of machine codebooks from Melbourne House is by DrIan Logan and, in the case o f TheComplete R OM Disassembly, writtenwith Dr Frank O'Hara. The books areexcellent value and contain a good dealof necessary information for the ma-chine code programmer.

Because of his knowledge of the Spec-trum ROM, Logan was asked by Sin-clair Research to write the routines forthe Microdrive ROM. As a result, andwith the blessing of Sinclair Research,he wrote the Spectrum Microdrive Book.It includes much information about thedrives, Interface One and the possibilityof adding or patching-in extra com-mands to the Basic.

The emergence of the book resultedin a rash of similar texts from publisherstrying to keep in the race for the most


up-to-date information. In most casesthe follow-up texts represented a re-arrangement o f the original but, unfor-tunately, that is not so with the newMicrodrive texts from Interface andSunshine Books.

When first exhibited at the PersonalComputer World Show in September,the Interface book was little more than aslim cardboard-bound photo-copy. I twas planned to use it as the basis for a'proper' publication. The Sunshine ef-fort, however, was better-presented.

The author o f the Sunshine MasterYour ZX Microdrive is Andrew Pennel,a friend of Logan. His book containedinformation which Logan's could not.One reason was that he was not limitedby what he could say. Although Loganspeaks with an authority which is diffi-cult to match, Pennel's book is slightlybetter as it contains information whichSinclair Research did not want used inLogan's book.

Even with the restrictions, however,the Logan book is good value so far asmoney and information are concerned.

The release o f the Microdrive textshas introduced a new area to the com-puter publishing market. We have hadbooks on machines, books o f listings,and books showing software techniquesbut there had, until then, been no bookson one specific peripheral for a ma-chine.

The Microdrive seems t o haveopened an area which could soon in-clude how to get the best from yoursound generator or using a disc drivewith a Spectrum. Book titles such asthat may seem absurd now but with theway books are becoming so machine-dependent, and with the search for newareas to write about, such titles maybecome available.

The information in the Melbourne


House book on the I'Vlicrodrive containsa good deal of machine code. The pub-lisher is s t ill determined to introducemachine language anywhere it can andthe release o f another machine codebook for the Spectrum was inevitablebefore too long. The new book is Super-charge Your Spectrum and many pagesare occupied by machine code listings.They include routines to search forstrings in programs, re-number lines,and delete blocks alines . I t has proved

'While the areas which belong to the gamesand utility sector have developed by leaps andbounds, the business and education markets

are still nothing more than a mess'

extremely useful to Spectrum ownerswho know nothing about machine codebut who want toolkit routines withouthaving to buy several cassette-basedprograms.

It is useful in another respect. I t ispossible for someone just learning aboutZ-80 machine code to read the programlistings and get an insight into howprograms are structured and the way inwhich some statements can work withothers. It also provides an incentive touse some o f the routines in your ownmachine code programs.

Not all publishers are interested inmachine code and tlyt market has plentyof support from companies with otherideas. Yet another new type of book waslaunched fo r the Spectrum b y Sun-shine. Until the release of SpectrumAdventures, by Roy Carnell and TonyBridge, computer owners interested inadventure games-playing or writing hadto rely solely on magazines.

The new book improved that s itu-ation, however, and showed the readerhow to write graphics adventures. Littleis said about decoding player responsesor generating textual adventures but thebook still marks a new area for publish-ers to exploit.

While the areas which belong to thegames and utility sector have developedby leaps and bounds, the business andeducation markets are sti l l nothingmore than a mess. Litt le has been done

in book form to aid this ailing thoughvery important part o f the industry.There have been a few general books onbusiness applications, such as Databasesfor Fun and Profit from Granada, butlittle business-orientated work has beendone.

The same is true of the educationmarket, although some publishers, suchas Granada and Longmans, are startingto see the potential. The object seems tobe to produce as many programmer-orientated books as possible. Unfortu-nately that leaves the market fo r thecomputer user who does not want to bebogged down by technology as undeve-loped as it was early in the year.

Several new areas in the publishingindustry inc lude machine code pro-gramming a n d programming tech-niques. They are over-developed andthat is proving expensive to the otherusers who want to use Spectrums athome or at school for accounts or home-work.

In the end that can only do themarket and, indirectly, computer manu-facturers, a good deal o f harm. Theareas in which computers can be used,such as education and business, will beunder-developed, Many children w i l lknow how to program but very few willhave ideas on how to use those program-ming talents.

Interface, 4 4 - 4 6 Earls Court Road, LondonW8 6EJMelbourne House, 1 3 1 Trafalgar Road,Greenwich, London S E MPuffin Books. Pengui n Books Lt d, Her -mondsworth, Middlesex.Shiva Publishing, 4 Church Lane, Nantwich,Cheshire CW5 5RCI.Sunshine, 1 2 - 1 3 Li ttle Newpor t Street.London WC2R 3LD.Granada, 8 Grafton Street, London W1 X3LA.

83

Program your favourite tune into your 48K Spectrumthen sit back and watch the notes appear on screen inauthentic musical notation as the tune plays. Thensend a copy to your ZX printer or save it on cassette 4and start composing a masterpiece of your own.

84

E5.75FOR T H I

48K SPECTRUM

.„ "Easy to use e n t e r t a in ing and instructive.., agood program that is well worth a listen."Personal Computer New0

NOW AVAILABLE AT SELECTED BRANCHES2-, OF W. H. SMITH

Also available by moil order from: Bellflower Software, 6 Rose-wood Avenue, Greenford, Middlesex. Enquiries: 01-903 1816.

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WHY YOU SHOULD HAUE 2 IIEW BOOKSFOR YOUR m a n ZH SPECTRUM... -toot

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allow yo u to p r i n t an extra 30% o r 60% morecharacters than the 'standard 3 2 ' d i rectly on toall 2 4 screen lines. Th is entirely separate p r in troutine comprises j u s t 8 2 4 bytes o f superfastZ80 m i c code, a n d enormously improves thescope o f you r 16/48k Spectrum to display textand data."Utterly simple t o use w i th Sinclai r BASIC ""Gives yo u t w o n e w high•clarity t y p e faces"*Adaptable to any BASIC & m/c code program"'Cassette has 1 6 /4 8 k codes + taped 'Gu i d e "Gamesters, adventurers, word-processers, spread-sheeters — just imagine the freedom and 'extra 'space yo u can n o w p r i n t w i th ! Y o u can b u yMicro-print 42 /51© fo r j u s t E5.00 f r o m y o u rlocal store, o r b y d i rect mai l f r o m

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S O N A L

..oSINCLAIR USER Annual 19144

One of the most popular sections of SinclairUser is our program listings. We have

reprinted some of the best, with two listingswhich have not been published previously.

SINCLAIR USER Amnia/ 1984 85

86

To help with entering graphics characters we have adopted asystem o f writ ing the characters fo r the ZX-8 1. We indicateinverse characters by the letter i and graphics by g, so that aninverse letter W is shown as iNICP and the graphics character on key6 is denoted by g6. Spaces i•re shown by sp and inverse spaces areisp. I f some occur together, for instance a row of six spaces, theyare shown by *6sp and where there is a combination of characterseach one is divided by a colon, thus spisp:6*g6 means a spacefollowed by an inverse space and then six characters on the 6 key.Where whole words are written in inverse letters they appear inthe listings as lower-case letters.In the Spectrum listings, letters to be entered in graphics modeare underlined, while other graphics instructions are underlinedand take the form shown above, with the addition that inversegraphics characters are represented by the letters " ig" .

KEN RYLETT of Burnage,

Manchester w r o t e So l i t a i r efor the I 6 K Spectrum to allow

people t o play the traditional game.Move one spot over the nex t t o anempty space. The peg which has beenjumped will then disappear. The aim isto finish with only one spot remaining.Moves should be entered as number,then letter.

Letters t o b e entered i n graphicsmode are underlined.

1015 GO SUB 9 0 0 01020 BORDER 5, P A P E R 5, I NK 0,

CLS1030 FOR n= 1 T O 6 41040 L E T P ( n ) 11050 P R I N T BRIGHT 1 ; I N K 2 ;

AT V ( n ) , H ( n ) ) " a "1060 NEXT n10701080 FOR n = 2 0 TO 1 4 8 STEP 1 61090 PLOT 6 0 , n. D R A W 1 2 8 ,0

1100 NEXT n11101120 FOR n = 6 0 TO 1 8 8 STEP 1 6

1130 PLOT n , 2 0 DRAW 0 , 1 2 81140 NEXT Ti11501160 P RI NT AT 2 , 8 ) " A B C D E F GH"

11701180 P RI NT AT 4 , 6 ) 1 ) A T 6 , 6 ) 2 ; A T8 , 6 ) 3 ) A T 1 0 , 6 ; 4 ; A T 1 2 , 6 ) 5 ; A T 1 4 ,6 )6 ;AT 1 6 1 6 ) 7 ) A T 1 8 , 6 ; 811901200 P RI NT AT V < 2 8 ) , H ( 2 8 ) ) " " ; A TV ( 2 9 ) , H ( 2 9 ) ; " " ) A T V ( 3 6 > , H ( 3 6 ) ;

" " ; A T V ( 3 7 ) , H ( 3 7 ) ) "

1210 LE T P ( 2 8 ) 0 L E T P ( 2 9 ) = 0LET P<36)1110, L E T P ( 3 7 )E 1 0

1220 LE T m ovel . c0, L E T P e g t o l t 60

1230 P RI NT PAPER 1 ; BRI GHT 1 ;INK 7 ; A T 0 , 0 ) " M O V E S " )m o v e s ;AT, 2 5 ; " P E G S l a " ) 15t o g s ; A T 4 , 0 ) P A P ER 6

) I N K 0 ; BRI GHT 1 ; " I NP UT " ) AT 5 , 0; " 9 9 T O")AT 6 , 0 0 " Q U I T . "

1240 P RI NT PAPER 6 ; I N K 0 ; BRI GHT 1 ) A T 9 , 0 ) " O NL Y " ; A T 1 0 , 0 ; " b c de";AT 1 1 , 0 ) " f g h i "2020 I NP UT PAPER 0 ; I N K 7 ; BRI GHT 1; " MOVE FROM ? " ; L I N E F $2025 I F FSim"99" THEN GO TO 3 5 6 02030 I F F S ( 1 ) < " 1 " OR M A W S "

OR F S (2> < "A" OR F $ ( 2 ) > " H "THEN BEEP 1 , 1, P R I N T P A PE R

2; I N K 7 ; BRI GHT 1 ; FLAS H 1 ; A T2 0 . 0 ; " O N L Y NUMBER THEN LETTER

e . 9 . 2 A ", F O R n =1 TO 2 50, NEXT

n1 P R I NT AT 2 0 , 0 ; "11 G O TO 2 0 2 0

GO TO 2 0 2 02035 P RI NT PAPER 1 ; BRI GHT 1 ;INK 7 ) FLAS H 1 ) A T 10;25;"F ROM " ;Fe

SINCLAIR USER Annual t9e4

2040 I NP UT PAPER 0 ; I N K 7 , BRI G HT 1 ; "MO V E TO " ; L I N E T $2045 I F T $ 009 9 " T H E N G O T O 3 56 0

2050 I F T $ ( 1 ) . ( " 1 " O P T $ ( 1 ) > " 8 "OR T $ ( 2 ) < " A " O R T$ ( 2 ) ) . " H"THEN BEEP 1 , 1, P R I N T P A P ER

2) I N K 7 ; BRI G HT 1 ; FLAS H 1 ; A T2 0 ; 0 ; " O N L Y NUMBER THEN LE TTE R

• . 9 . 2 A ", F O R n ml TO 250 NEXT

n, PRINT AT 20;0;"

GO TO 2 0 4 0

2055 P RI NT PAPER 1 ; BRI G HT 1 )INK 7 ; FLAS H 1 , A T 1 2 , 2 5 , " T OT$20602070 LE T f m ( ( CO DE F $ ( 1 ) - 4 9 ) * 0 )44CODE F $ ( 2 ) - 6 4 )2080 LE T t m ( ( CO DE T $ ( 1 ) - 4 9 ) * B ) + (CODE T $ ( 2 ) - 6 4 )

2090 I F P ( f ) 0 OR P ( t ) m l THE NBEEP 1 , 1, P R IN T P AP ER 2; INK 7)

BRIGHT 1 ; FLAS H i l A T 2 0 , 6 ;I NVALI D MOVE " ' FO R nm l T O 2 5 0• NE X T n . P R I N T AT 2 0 , 6 ; "

" ; AT 1 0 , 2 5 ; "" G O TO 2 0 2 0I .AT 1 2 ; 2 5 ;

21002110 LE T d i f f v m V ( f ) - V ( t )2115 LE T d i f f h m H ( f ) - H ( t )2120 I F d i f f h = 4 AND d i C f v = 0THEN GO TO 3 1 0 02130 I F d i f f h m - 4 AND d i f f v = 0THEN GO TO 3 2 0 02140 I F d i f f v m 4 AND d i f f h = 0THEN GO TO 3 3 0 02150 I F d i f f v m - 4 rAND c i l6f h = 0THEN GO TO 3 4 0 0

2160 BEEP 1 . 1 P P I N T PAPER 2 .INK 7 ; BRI G HT I ; FLAS H 1 4 1 T 2 0 , 6

I NVALI D MOVE " . FO P nm lTO 2 5 0. N EX T n. PRINT AT 20,6,"

" ; AT". G O TO"JAT 1 2 , 2 5 ; "

2 0 2 03120 BEEP 1 ; 13125 I F P ( t e 1 ) = 0 THE N GO TO 4 0 0 03130 P RI NT I N K 2 ; A T V ( t ) , 1 4 < t ) ; " 1"; AT V ( t ) , H ( t . + 1 ) ; " " A T v ( f > , w 4

3140 LE T P ( t ) m l, L E T P ( t .+ 1 ) m 0

LET P ( f ) 03150 GO TO 3 5 0 03220 BEEP 1 , 13225 I F P ( t . - 1 ) m 0 THEN GO TO 4 0 0 01030 P RI NT I N K 2 ; AT V ( t_);H,:: t ) ; " a") AT V ( t ) , H ( t - 1 ) ; " " ; A T V ( f ) , H ( f>;"3240 LE T P ( t ) - 1 L E T P t - 1 > m 0- LET P ( f ) - 03250 CO TO 3 5 0 03320 BEEP 1 ; 1

. .

. .

.3325 IF F(t+e).el THEN GO TO 4000

3330 P RI NT I N K 2 ; A T V ( t ) , 4 ( t ) ; " a" ; AT V ( t . . 1 - 8 ) , H( t ) ; " " ; A T V ( f ) , H ( f

j 0 ,

3340 LE T P ( t ) m l ! L E T P ( t . +8 ) m 0- LET P ( C) m 03350 GO TO 3 5 0 03420 BEEP 1 , 13425 I F P ( t - 8 ) m 0 THEN CO TO 4 0 0 01430 P RI NT I N K 2 ) 8 T V ( t ) , H ( t )," .1

"J AI V ( t - B ) , H ( t ) ; " " J A T V ( f N ; H ( f> 13440 LE T P ‹ t L E T P ( t - 0 )mO

LET P ( f )m03520 LE T movesmmoves+13530 LE T P e a s . p p - 13540 P RI NT PAPER 1 ; I N K 7 ; AP I G H

T 1 , A T 0 ; : i i , " •o,v;potgs35-471 IF p.E.t..1 THEN PRINT AT 10,

" ; AT 1 2 ; 2 1 . "GO TO 2 0 2 0

1560 I NP UT PAPER QJ I N K 7 ; BRI G HT 1 ; FLAS H 1 ) " E ND O F GAME , ANO THER 7- " , L I N E A $ I F A$ = " " THE NGO TO 3 5 6 03565 I F Fo$="Y" THE N GO TO 1 0 2 03570 STOP35004000 REM T N V A L I D MOVE40104020 P RI NT PAPER 2 ; I N K 7 , P RI G HT I , FLAS H 1 J AT 2 0 , 0 ; " I NV AL I D mOVE " ' FO R n= 1 T O 2 5 0, N E X T n- PPI NT AT 2 0 , 8 j . " . A T

1 0 , 2 5 ; " " ; A T 1 2 . 2 1 ; "GO TO 2 0 2 0

40109000 REM S E T UP9010902090309035

9050906090709080

126,9 1 0 09 1 1 091209130914091109160917091809190.9210922092309240

9250926092709280929093009 3 2 09340935093609370938093909400941094209430

DIM P ( 6 4 )DIM V ( 6 4 ) ! D I M H ( 6 4 )DIM F $ ( 2 ), D I M T S (2 )

FOR n = 0 TO 7READ • . P O KE USR "A"+11,1*

NEXT nDATA 6 0 , 1 2 6 , 2 1 7 , 2 5 5 , 2 1 5 , 2 5 560FOR nm l T O 0

LET V ( • )LET V ( n40 ) m 6

LET V ( n+ 1 6 ) m 8LET V ( n+ 2 4 ) m 1 0LET V ( T0 - 3 2 ) m 1 2LET V ( n44 0 ) m 14

LET V ( n+ 4 8 ) m 1 6LET V ( n4- 5 6 ) m1 0

NEXT nFOR nm l T O 5 7 STEP 8

LET H ( n ) m ALET H ( n + 1 ) = 1 0LET H( n+2 >m 1 2

LET H(n4 -3 )m14LET H(n4 -4 )m16LET H( n+ 5 ) m 1 eLET H(n-P6)m20LET H( n+ 7 ) m 2 2

NEXT nPOKE 2 3 6 5 8 , 0FOR nm0 TO 7

READ b. P OK E

READ c •READ d.P E W e .READ f.READ S.READ hREAD

NEXT n

9440 DATA 0 , 0 , 0 , 0 , 1 2 7 , 2 5 4 ; 1 , 1 2 0 .0 ; 0 ; 1 ; 1 2 8 , 4 2 , 1 2 . 1 , 1 2 6 . 0,0 ; j , 1 9 2 ;2 4 , 2 4 , 1 , 1 2 0 , 0 , 0 , 7 , 2 2 4 , 0 . 0 , 5 , 1 6 0 ,0 ; 0 ; 5 ; 1 6 0 ; 0 , 0 , 7 , 2 2 4 , 2 4 , 2 4 , 1 ; 1 2 0 ;

1 2 7 ; 2 5 4 , 1 , 1 2 8 , 0 ; 0 , 1 ; 094500460 PFTURN

01011M

POKEPOKEPOKEPOKEPOKEP0VEPOKE

LISPUSP

USRUSRUSRUSRUr_.R

" C" + n, c

"E"-P.n,e

"C"-o-n;'J"H". . n, h" I " + n , t

• • • • • . •

SINCLAIR USER Annual 1964 8 7

88

8 CLS 170 FOR N. .1 T O 49 PRINT "START?" 180 IF D( t1 -1 , N) . . 0 THEN GOTO 2 2 0

10 INPUT A$ 190 NEXT N11 LET R. . 31 200 LET M..11-112 LET M.--7 210 GOTO 1 7 012 DIM D ( 6 , 4 ) 220 LET G..R—M*INT KP,11)14 LET 11.0 230 I F R4.1. . INT ( R / M ) THEN LE T Gl b CLS ( R N E W M - 1 ) )19 FOR N i T O 6 240 FOR N. .1 T O 420 PRINT N* 1 1 1 1 250 IF E X G AN)

,. . 0 T H E N G OT O J 00

30 NEXT N 260 NEXT N35 PRINT AT 9,0J"TARGET. . 3 1 " 270 LET G. .14-INT ( R N D V M - 1 > )48 IF AS (1 ) . . "Y " THEN GUTO 2 2 0 280 GOTO 2 4 0

100 PRINT AT 10, 0)"NUMBE R?" 300 PRINT AT G - 1 , N - 1 ) " . "110 INPUT N 310 LET FtR—r.i111 LET N. . I NT ABS N 315 PRINT AT 1 0 ; " T O T A L " ) 3 1 — R112 I F NOT N OR N>M-1 THEN GOTO 316 IF R

,. 0 THEN UUTO 350

110 317 IF R. (0 THEN GUTO 3 4 0113 IIPRINT AT 1 8 1 0 ; " 320 LET D(G , N) . . 1120 FOR R.11 T O 4 330 GOTO 1 0 0130 IF D< N1A). . 0 THEN (UT O 1 4 5 340 LET140 NEXT A 350 I F .

N -1 THEN PRINT AT 12,0;"

145 PRINT AT N - 1 , A - 1 J " . " YOU WI N. "150 LET C A N , A )

,e 1

360 IF 11.0 THEN P RI NT AT 1 2 , 0-160 LET RR— N I W I N . "

164 PRINT AT 9, 0;"TARGE T= 3 1 " 370 PRINT "AGAI N?"165 PRINT AT 10, 0;"TOTAL7. ";31—R 380 INPUT AS166 IF Ro.0 THEN GOT° 3 4 0 390 IF A S ( 1 " Y " THEN RUN167 I F R< 0 THEN GOTO 3 5 0 400 STOPOP

Li

NEWHEN START? is displayed

enter M i f you wish to playfirst or Y i f you would prefer

the computer to start. A set of counterswill then be displayed, f o u r o f eachnumber from one to six. You and thecomputer take turns i n remov ing anumber to add to the total. The winneris the player who brings the total to 31.

Written for the 16K ZX-81 by j HEntwistle o f Cheltenham, Gloucester-shire.


SINCLAIR USER elnnuat 1984

SHFLOWKAREN CRUICKSHANK of

Guildford, Surrey has sent a pro-gram for the Spectrum, based on

the workings of the Stock Exchange.You are given a working week in whichto make as much money as possible bybuying and selling stocks and shares.Each day you must decide eight timeswhether to buy or sell bonds.

Decisions you can make are based onthe information given, including howmuch cash you have in hand and themarket forecast. Beware—your bosscould arrive at any minute and decide toalter your cashflow situation. I t is anoriginal game calling for planning andskill. Can you make sufficient money tobe appointed manager at the end of theweek?

1 L E I H 5 = 0• L E T 5 = 1 0 : L E T C A = 1 0 0 0 : L E T

D = 1 0P A P E R 0 : I N K : S U R v E R O . m a

R I G H T 1 - C L E5 F O A 1 J = 1 T O . 5 I F W = 1 T H E N P

q I N T -1 1 1 12 S e nr

7 I F W = 2 T H E N P R I N T8 I F U = 3 T H E N P R I N Ta

-

U E 5 D A 1; NE

9 I F U = 4 T H E N P R I N T " M M R I A N N W S: Z1 0 I F U = 5 T H E N P R I N T -

1 4 P R I N T F L A S H l ' " A N E U W O R K I NG D A Y "

1 5 P O K E 2 3 5 5 8;82 0 F O R 0 = 1 T O 1 2 : B E E P 0 0 5 0 -

N E X T 01 2 0 F O R D = 1 T O 81 2 2 L E T R N = I N T ( R N D * 1 0 )1 2 3 G O S U B 2 0 0 01 2 5 P R I N T - -M E L I C I N EE E K I A M AM -;

1 2 7 I F P < 0 T H E N L E T P = 02 3 5 L E T 0 = I N T ( R N D * 5 )1 3 8 P R I N T P A P E R 8 ; I N K 0 ; " " R E P1 3 7 I F C A > = 0 T H E N P R I N T " C A S H A

T H A N D E-; C A

1 3 9 I F C A t O T H E N P R I N T ” O V E R D R AF T f-; C R

1 4 0 P R I N T 1 5 ;- B O N D S A T E " ; P;- E

P C H- 1 4 5 P R I N T -

O V E R A L L A S S ET S f ”; IF

t 5 ) + C R1 5 0 P R I N T- -M A R KE T F OR CA ST -;

1 6 0 I F 0 = 0 T H E N P R I N T " S T E A D Y " :L E T r L,=-P 4 - 1 IN T ( RN D* 3) -2 )

1 7 0 I F 0 = 1 T H E N P R I N T -C H A N G E R SL E " : L E T P = P o - f I N T ( R N D * 2 : 3 Y - 1 0 )1 5 0 I F 0 = 2 T H E N P R I N T -P L U M M E T TI N G

-: LET P=P4-(INT (RND*50)-40)

1 9 0 I F 0 = 3 T H E N P R I N T " R I S I N G-:L E T P = P 4 - ( / N T ( R N D * 5 0 ) - 1 5 )1 9 5 I F 0 = 4 T H E N P R I N T -U N C E R T R IN ! " : L E T P = P 4 - 1 2 N T 1 R N D * 5 0 ) - 3 0 )2 0 0 I N P U T -S E L L O P B U Y? -;5 4 $

2 1 0 S E E P 0 . 0 5 , 5 02 2 0 I F A $ = " 5 E L L- T H E N G O T O 5 0 0

2 3 0 I F A $ < )-B U Y " T H E N G O TO 2 00

2 4 0 L E T N 5 = I N T ( R N D * 1 0 0 ) t 2 52 4 2 P R I N T "-T H E R E A R E -, n s .- 8

O N D 5 R V A I L A B L E- 4 3 I F P 8 = 0 T H E N L E T 1=0. . 1

2 4 5 P R I N T -H O U M A N Y B O ND S AT E-

P , " E A C H "2 5 0 I N P U T X2 5 5 B E E P 0 . 0 8 , 5 02 5 7 I F X > N 5 T H E N P R I N T S A I D- i N 5 , - B O N D S . N O T -; x ;- B O N D 5-:

L E T N 5 = N 5 - 1 : G O T O 2 4 22 5 0 I F C R ( C R - P f X T H E N P R I N T " N O

T E N O U G H M O N E Y " : G O T O 2 4 02 7 9 L E T C A = c A - p * x'm.90 L E T B = 8 4 - X2 9 5 P R I N T3 0 4 N E X T D3 0 5 G O T O 7 0 05 1 0 L E T B U = I N T ( R N D * 0 0 0 ) i - 5 05 1 5 I F P < = 0 T H E N L E T P = 1

5 2 0 P R I N T I l A R K E T P R I C E L-, P5 2 5 P R I N T B U;- B U Y E R 5 W R N TI N G E

U N D-b

5 3 0 P R I N T -H O W M A N Y B O ND S TO SE

L L '7 -5 4 0 I N P U T 5

5 4 5 B E E P 0 . 0 9 , 5 05 4 8 I F 5 , B U T H E N P R I N T " " X 5 A I

D ' , S U , " B U Y E R S ' L E T B U = B U - 1 C .O T O 5 2 5

5 5 0 I F S ‘ B T H E N P R I N T -Y O U H A V EN' T T H A T M A N Y B O N D S " G O T O 5 3 05 5 5 I F 5 ( 0 T H E N G O T O 5 2 55 5 0 L E T C A = P f 5 . 1 . C R5 9 5 L E T 6 = 8 - 55 0 0 P R I N T " N E X T D7 0 0 F O R 0 = - 3 0 T O 3 07 0 5 B E E P 0 . 0 0 5 , 07 0 5 N E X T 0-'10 IF L.1>5 THEN PRINT ""-THE

E N D O F T H E D R Y '7 1 5 I F 1 , I = 5 T H E N P R I N T M E R E

7 2 0 P R I N T -C A S H -; C A7 3 0 P R I N T B ; " B O N D S A T f-; P7 4 0 P R I N T -T O T A L A S S ET S f ";

T 0 = ( P * 1 3 ) . . - C R- P R I N T 0

7 4 2 I F U = 5 T H E N G O T O 7 4 97 4 5 I F I N K E Y $ = "- T H E N G O T O 7 4 E

7 4 7 C L S : N E X T t o7 5 0 I F 0 ( 0 T H E N P R I N T " Y O U ' R E

F I R E D7 5 0 I F 0 ) 0 A N D 0 < 9 0 0 0 T H E N P R I N

T " Y O U D O N O T U S E E N O U G H I N I T I A TI : U E- .

755 IF 0)9000 AND 0(25000 THEN

P R I N T -P R O MO T I ON TO HERD CA5HIER

f -7 7 0 I F 0 ) 2 5 0 0 0 A N D 0 ( 4 5 0 0 0 T H E NP R I N T " P R O M O T I O N T O C H I E F S U P E R

V I S O R. 7 7 5 I F 0 > 1 1 5 T H E N L E T 1 1 5 = 0

7 8 0 I F 0 ) 4 5 0 0 0 T H E N P R I N T -T H EM A N A G E R S 5 E 9 T A W A I T S Y O U

- 7 5 5 P R I N T ' H I G H S C O R E f " ; H S7 9 0 P R I N T ' " " P R E S S A N YK E Y-5 0 0 I F I N K E Y $ =- - T H E N G O T O 5 0 0

8 1 0 C L S G O T O 22 0 1 0 I F R 1 4 = 1 T H E N P R I N T - -S U D D EN D E V A L U A T I O N H A S M E R N T-: P R I N T" T H A T T U O B O N D S A R E B E I N G N E R G E D• P R I N T -I N T O O N E .I E : C UT IN HA

L F-2 0 0 0 I F R N = 1 T H E N L E T B = I N T ( 1 5 , 2

2 0 2 5 L E T C = / N T ( R N D * 3 )2 0 3 0 I F R N = 2 T H E N P R I N T —1 5 0 5 51 5 C O M I N G A R O U N D C H E C K I N G .-: P A U5 E 1 0 0 ! I F C = 0 T H E N P R I N T *-H A D Y0 U W O R R I E D 2040 IF RN=2 A N D C = 1 T H E N P R I N T" H E C U T S O F F Y O U R C A S H S U P P L Y B Y- : P R I N T -H A L F . t H A ; HA , H A )" : LET

C A = C A , 22 0 5 0 I F R N = 2 A N D C = 2 T H E N P R I N T' G I V E S Y O U E X T R A 1 0 0 B O N D S .-: L E

I B = B 4 - 1 0 02 1 0 0 R E T U R N

E

89

90

10 COSUB 1 0 0 020 CLS30 LET W=035 LET SH.r140 LE T T = 3 045 LE T S a 050 LET 2 = 360 LET Ra 2 5 065 FAST70 P RI NT AT 1 , 0 J " ( 3 2 * i s ) "75 FOR La.2 TO 2 080 P R I N T." ( i s t 3 0 *s P,i s ) "

e t NEXT L90 P RI NT AT 2 0 , 0 J " ( 3 2 * i s ) "91 P RI NT AT 0 , 0 ) " E N

ERCY"95 LET C a l °

100 LET Bal e)105 FOR-A-1 T O T110 LET X = I NT ( R N D * 1 8 ) + 2115 LE T Y a I NT (RND* 29 )+ 1120 P RI NT AT X , Y )CHRS 2 3125 NEXT A127 SLOW130 P RI NT AT C, B)" (911 )"135 LE T C a C + ( I N K E Y S Z7 -6 " ) - ( I N K E Y

1,047n)

140 LE T 8. -B+ (I NKE Y S = "8")- ( I NKE Ys = " 5 " )

145 P RI NT AT C , B )150 LET P=PEEK (PEEK 1 6 3 9 8 + 2 5 6 *

PEEK 1 6 3 9 9 )155 I F P a 2 3 THEN COTO 2 0 0160 I F P = 128 THEN COTO 2 2 0166 I F PaCODE " ( 9 h ) " THEN P RI NTAT 0 , W ; " "167 I F PaCODE " ( 9 h ) " THEN LET W

.44+1168 I F W= 10 THEN COTO 2 3 0170 I F P = 58 THEN GOTO 5 0 0l ee P RI NT AT C , B " 0 "185 LE T 5a5+ 1190 I F S>R THEN P RI NT AT 2 0 1 0 ,J

"UUU"195 GOTO 1 3 0

200 LE T Z = Z - 1205 PAUSE . 5210 I F 2 = 0 THEN GOTO 2 2 0215 GOTO 1 3 0220 P RI NT AT 2J1;"GAME OVER"JTA

8 20;"S CORE = ";S225 STOP230 P RI NT AT 2A1; ;"Y OU RAN OUT

OF ENERGY", TAB 15J"SCOPE=";S235 STOP500 CLS510 P RI NT "YOU COMPLETED SHEET

"JSH)T88 2 0 ; " S C O R E.r " J S515 P RI NT " L I V E S J 2520 P RI NT "MORE OBSTACLES WI LL

NOW APPEAR"525 PAUSE 2 0 0530 CLS535 LET W=0540 LET T - T + 3 0545 LE T P = R+ 175547 I F S H ) . 3 THEN LET P=R4-125550 LET SH=SH+1560 GOTO 6 5570 STOP

1000 P RI NT " M O L E "1010 P RI NT AT 2 , 0 ) " Y O U STEER YOUR TUNNELING MOLE, A V O I D I N G THE"

"AND YOUR OWN T U N N E L S " " ( 9h ) " " . I F YOU H I T ONE OF T HE " " U"1 7YOU CAN CO ONTO ANOTHER S C R EEN."1020 P RI NT AT 7 , 0 J " I F YOU H I T A""*""YOU WI LL LOOSE A L I F E . "1030 P RI NT AT 9 , 0 ; " I F YOU H I T T HE BORDER YOU LOOSE ALL YOUR L I V EC. • "

1040 P RI NT AT 1 1 , 0 . " I F YOU H I T YOUR OWN TUNNEL YOU L OOS E SOME 0F YOUR ENERGY. T H E SAME I FYOU STAY S T I L L . "1050 P RI NT AT 15, 0;"CUR5OR KEYSTO MOVE. ")TAB 10;"P RE S S A KE Y . "1060 PAUSE 4 E 41070 RETURN

•

STEER your tunneling Mole

through the ground. Hi tting astone will cause you to lose a life

and hitting the border will kill you. I Iyou remain still, or hit your tunnel, youwill lose some energy. Eating a worm"V" will move you to another screen.

The program was written for the I 6KZX-8I by Simon Reeve of Chessington,Surrey.

Graphics instructions are given i nlower-case letters within brackets. Aspace is represented by 'sp', a graphiccharacter by ‘g1, a n d a n i n v er s e c h ar a c-

ter by 'i '. Thus 'gh' represents graphicH.


Moresensational sof twareZ)C811BreakoutBomberScreed*Space ImamPullmanfnids0.115 EACHAstern*TomeiRescuela Samesank64.115 EACHMho al Saler* Acton to Earth

=l i euSt 54

Spectrum 16KScrambleUntie holmMies al Salm/ Rem to ErnSpace Zombies

GelationTempestMausCreepy emittert5.95 EACH

Spectrum 48KthstenatsiStutertel Cashla M rthaMid MirthStar TrekPot the PostmanHenanLaurin;PerianthAseekautTimeguestBea Molina & HealySAS A muttLaud al SagaaCruise AttackULM EACH

ot 4?,w Mikro r- lming soon - watch o thc -- •

Please make cheques/PO payable to •Mikro-Gen' and add 40p post & packing per order. Send mail orders direct to:Available bum LiohtPC& Tigw, W peserilm, Co o p .Nialalbla a ()that wading Istolloni.

PHONE YOUROR ACCESSNUMBER

••••%--

- • ° S

1 4 4 1 1 r e4 ri g l i tl .

M e k r o-G e n , 1 D ev on sh i re C ot ta ge s, London Rd, Bracknell RG12 2T0 Tel: 0344 27317

srNctAtR. USER Annual 1984

92

I I

I I

220 L E T C=C—CODE " C OS2 3 0 GOTO 8 0240 I F I N T ( R N D * 1 0 ) < > 5 TH E N GOT

0 V A L " 1 6 0 "2 5 0 P R I N T A T CODE " ( S 5 > " , 0 ) " C O R

260 L E T C = C + I N T ( R N D * 5 ) 4 - 1270 GOTO 8 0300 P R I N T "BANKRUPT"310 S TOP400 I F E < ) 0 TH E N r ;OTO VAL. " 9 0 "410 P R I N T " P R O F I T . W ) S - 2 0 0

10 GOTO 4 020 L E T S = 9 + C — ( E * 4 >30 GOTO 6 040 L E T A=CODE " ( S 250 L E T S=CODE " C OS60 L E T E = P I — P I70 L E T C = E80 P R I N T A T 0 , 0 ) " C R E D I T $ " ; S A "" J A I 1 , 0 J " M I N E D I I " J C J " " , " D E P

TH " , E ; "90 I F S < 0 TH EN GOTO V A L " 3 0 0 "

100 I F E > 2 0 TH E N L E T A = 8110 I F I N K E Y S = " 7 " TH E N GOTO 2 0120 I F IN K E Y S = " 6 " TH E N GOTO V A L"150"130 I F I N K E Y * = " S " TH E N GOTO V A L" 4 0 0 "140 GOTO V A L " 9 0 "150 L E T E = E + P I / P I160 I F I N T CRND*CODE " = " ) > A TH E

N GOTO V A L 1 12 0 0 "170 P RI NT AT CODE " ( 9 5 ) " , 0 ) " G O L

180 LE T CC-I . I NT (RND*CODE "<.7.4s)1>4.CODE "Cgs)"

190 GOTO 8 0200 I F I N T (RND* 1 6 0 / A)< >CODE

THEN GOTO VAL 1 12 4 0 "210 P RI NT AT CODE "(go5)" , 0J"E X P

) I tI I

• • o • • •• •—

• • • • • • •

you START with $200 in the

bank and your aim is to make aNmuch profit as possible from

your mine. It costs you $4 to dig on(metre and each time you return to di(surface your funds are altered to takeaccount of your profit and expenditure.

You may find coal (coa) or gold (gal),or you may be unlucky and be involvedin an explosion, which will cost you$200. Key 6 moves you down the mineand key 7 returns you to the surface.

Mark Evans of Welling, Kent wroteMiner for the I K ZX-8I.

SINCLAIR LSER eimmal I9B4

pHILIP HARPER, aged nine, of

Benfleet, Essex sent Ski-Run forthe I 6 K Spectrum. Manipulate

your skier round the flags using cursorkeys 6 and 7. You have 10 lives i nwhich to complete the ski run as manytimes as possible.

It is an ideal game for people whofind that manipulation of characters bythe use of four or eight keys is, as yet,beyond them.4 Graphic S, graphic FR Graphic L


I R E M " s i t i-: C L S2 L E T 5 = 1 0 : P R I N T F L A S H 1 ; I N

K 2 ; P R P E R ' 6 ; A T 1 , 5 ; " P L E A S E S T O PH E T A P E " : P R I N T A T 2 . 3 ;-P r e s s

I n y ) ( e y 1 0 c o n t i n U e-: P A U S E 0

3 C L S G O S U B 1 0 0 04 P R I N T A T 1 , 1 3 ;-5 K 1-,-5 1 t i i s

a g a g e o f s k i t i a n d i t i s-;-a t s

o v e r y a d d i c t i v e .l i s e K e y s 6 & 7 t o s t e e r y o u r- ;-.Aer,4_11)pround the ftags,(111)

▪ , Y o o h a v e g o t 1 0 L i v e s ' :I N K I : P R I N T : P R I N T P R I N T -P r e s s a n y K e y t o c o n t i n u e " : P R O SE

5 G L S P R I N T A T 1 0 , 0 ; " 5 i t i e r sL e f t-; : FOR f=s TO 0 STEP -I: P

3 I N T I N K 1 ; " A - ; , N E X T f : I F s = -1 T H E N G O T O 5 0 0 0

6 L E T 3 = 1 : B O R D E R 5 : P A P E R 7.I N K 27 P R I N T B R I G H T 1 ; P A P E R 7; _ I N

K 2 ; A T 1 , 0 ;- -

,AT 2,0.; BRIGHT 1;

P R P E R 7 , I N K 2 ;-

8 P R I N T P T 3 , 0 ; I N K 0 ; P A P E R

, A T 4 , 0 ; P A P E R 7 ;- -

;AT 0,0.; INK 0; PAPER 6

9 P L O T 0 , 0 : D R R W 2 5 5 , 0 : D R R U0 , 1 7 5 : D R R U - 2 5 5 , 0 : D R R U 0 , - 1 7 5

l e F O R 1 = 1 T O 3 12 0 P R I N T B R I G H T 1 ; P A P E R 7 ; I N

K 1 ; R T a , f ;-_ h "

2 1 I F ( 3 = 1 ) F I N D f ( f = 5 ) O R ( r i m 'S ) O R t f = 2 7 ) ) T H E N G O T O 3 0 0 0

2 ( , 3 = 2 ) A N D ( i 1 = 4 ) O R ( ( = 13 ) O R ( 1 = 2 2 ) O R ( f = 3 1 ) ) T H E N G OT O 3 0 0 0

2 5 B E E P . 0 0 2 , f : P R I N T A T a , f ;B R I G H T I ; P A P E R 7 ; "

2 6 L E T a = a 4 - ( I N K E Y $ =- 6 - A N D .3 ( 2

) - ( 1 N K E Y $ =- 7 - A N D .3 ) - 1 )

3 0 N E X T f3 5 L E T • 1 = 9 + 14 0 P R I N T F L A S H 1 ; P A P E R 1 ; I N K

7 ; R T , 1 0 ;-U E L L D O N E! ! "

5 0 B E E P . 1 , 5 . P A U S E 5 : B E E P . 16 : P R U 5 E 5 : B E E P . 1 , 5 : P A U S E 5 :

' B E E P . 1 , 6 : B E E P . 9 , 86 0 G O T O

1 0 0 0 L E T 9 = 0 : F O R f = 0 T O 7 : R E A D1 : P O K E U S R -5-4 - 1 , Z : N E X T f

1 0 2 0 F O R 1 = 0 T O 7 : R E A D z : P O K EU S R -I-3 4 , z: NEXT f

1 8 2 0 F O R F = 0 T O 7 : R E A D z : P O K EU S R N E X T f1 0 4 0 F O R 1 = 0 T O 7 : R E A D z : P O K EU S R N E X T f1 0 9 0 R E T U R N2 0 0 0 D A T A B I N 0 0 0 1 1 0 0 0 B I N 0 0 0 1 10 0 0LB I N 00010000 ,BIN 06011111,61'

N 0 0 0 1 1 0 1 0 , B I N 0 0 0 1 1 0 1 0 . B I N 0 0 0 10 0 0 1 , B I N 1 1 1 1 1 1 1 12 0 1 0 D A T A B I N 1 0 0 0 0 0 0 0 , B I N 1 1 1 0 11 1 1 , B I N 1 1 1 1 1 1 1 0 , 5 1 N 1 1 1 1 1 1 8 0 , B IN 1 1 1 1 1 1 1 0 , B / N 1 1 1 1 1 1 1 1 , 5 1 N 1 0 0 00 0 0 0 , B I N 1 0 0 0 0 0 0 02 0 2 0 D A T A 2 5 5 , 0 . 0 , 0 . 0 , 0 . 0 . 2 5 52 0 4 0 D A T A 0 . 0 , 0 , B I N 0 1 0 0 1 0 0 1 , B I N

0 0 1 0 1 0 1 0 , 0 , B I N 0 0 1 0 1 0 1 0 , B I N 0 1 00 1 0 0 13 0 0 0 F O R q = 0 T O 7 : P R I N T B R I G H TI ; P A P E R 7 ; F L R S H 1 ; I N K I N T ( R NV * 7 ) ; A T a , T ;-=-

3 0 1 0 5 E E P . 1 , - 4 5 : N E X T q3 0 1 5 L E T s = s - 13 0 1 6 L E T g = g 4 . 13 0 2 0 G O T O 6 04 0 0 0 5 T O P5 0 6 0 P L O T 0 , 0 : D R A W 2 5 5 , 0 : D R A UO, 1 7 5 : D R A U - 2 5 5 , 0 : D R A W 0 , - 1 7 5 :

P R I N T A T 6 , 7 ;-W a n t a n o t h er g o ?"

g107 7

5 1 S M-P 4-inl.: 1 ,-Y o u finished

w i t h -A s i ;" r un s-

▪ 0 7 0 I F I N K E Y $ = " y " T H E N C L S : L ET s = 1 0 : G O T O 55 0 8 0 I F I N K E Y $ =-n- T H E N C L S : G O

T O 4 0 0 05 0 9 0 , G 0 T O 5 0 7 0

(3

4

PLANE SAILINGBBC Mackil A anti Wide II

AIRLINE

O P T ;• •

ri ST R AT EGY GAM ES

C R I M E A wing and a pra •nor be enough to turn your im ike, t o EBB mi ll ion in the ems

a fc.ocl. but your rinanCel wizardrywill enable you to take over Brit ishAeways, o r wa 41 Runs on D0E1118$ E S and Spectrum 16K)48K

ES

CORN CROPPER L i- • i iare • !wc, o f I re, r, •,

lacing n e Farmer Pla n t irg fertilizingand harvesting must a ll be clone0 0 0 0 0 d n iCan y i f r a n a r e t o re ap t h erewards ottered ei corn cropperRurr. • ' 1 6 K - ES andSice • ' K 4 8 K - ES

AUTOCHEIF You have a ndlkOncapita arid reed to increase ttvs toE25 ma im in the shorteg timepossible Inflation g n ke s sluggishmarkets are only some of theh az ar d s t o O Ve rCiarn e R u n s a n

ZKEll 16K — £5 end SPectri -161Q48K - ES

SMUGGLER • a 19thcei itur y y b e t w e e nEngland and the continent visit irgports to buy and eat yout cargobut beware the customs men.;Juges and gate force winds can allrun you aground Runs onSpectrum 481< - ES

DALLAS Can you • 'toughpet..., dollars to lake , C u i n gCut throat business and aneye icy the man chancre may getyou there but you'll need nerves atsteel to become the re krrig ofDallas Ru n s on ZX81 I SK - ESand Spectrum I61<14SK E S

PRINT SHOP In print shop ares c nedulog S tafFing. p u l th a i c tu arx1Ltuolorkg within this time lime will testyCko buOneSS ac um en to th e t i eand vreekly balance sheets wiltWive the Quality o f your decisionmaking Runs on ZXBI 161< - E..and Spectrum 1151<4EI1< - ES

PLUNDER ca nco Spain s beardSpanish sh ips on the high seassurvive that broadsides andplunder the gold destined ICX the4 ,, to and you might get your

I'. •ld betOre FraitOS Drake

• Spectrum 48K -

sc., •GANGSTERS!

A mi l

1101yS

TRATEGY GAMES

GANGSTER c o l dand cailous ,. 0 .,J r 1 t o w a r re r . 1 $

Idle Of Don Yo u need to be it youare to rise to the lop or the pole AQuick trigger finger and an evencpuicker b ran are needed to coratothe mobs and their rackets Runeon Spectrum 481< - ES

BRITISH kJWI AN O y,a ' I i f yO u r s r i • wtscat pxrpany but you have anoverdraft to repay and a workInene tobe kept happy Steer your ve y toWd;CeS5 with (WOO managementand industrial relahore Ru re onSpectrum 48K E t

Available from W H Smith, Boots, Rumbelows and all good computerCases Computer Simulations Ltd., 14 Langton Way, London SE3

ABYSS k ,ourney aur., ! r ebng forgotteir AWN. and outset theeat morMens that kirk n the stedowsawaiting the 0001tordy and carelessadventurer There are many bedg ie .and many moristerS OM you be theonelo make the Abyss sate to acesagain Runs on Spere in , 481< E s

BYTE. . , . 011.1.11 , , u' wed k , t,d ,k , , , . , ,p t a i l i f s y e mthen return home Ea sy Byt e PIGSsent a l eleCtiorsC mongers to harryyou through the 'twee An e m o n e 'maze of o rcu ilry i f any of thorncatch yo u R u n s on SpectoUnt48K - 0

CAME I

SC Strategy Games. They're no pushover

! Arthur• w w e n

' .41trig Orgy to the

, a n d EveP I P101 l o i l d i n y o u r w a y

arid make a triumphant return toCamelot to be crowned King Runson zxa l 161< - E5 and Spectruni48k V C

shops or

GI t I . 0

M I W I

1 L E T z i = 0 L E T L L 1z * 0

10 GO SUS 102011 CO SUB 950015 LET r n. l L E T tr . - -,4 B O R D E R 6

PAPER 7 . I N K 220 PLOT 891145 DRAW I NK 3 , 7 . 0PLOT (894-I NT 1 / 5 0 ) , 1 4 5 t DRAW I

tor 9 , I NT wi.15e,e1

100 1 5 0 2 0 E . 2 5 0 3 0 0 "240 PLOT 8 8 , 1 6. D R A W 0 , 1 5 9, P LO

T 0 , 1 4 4 DRAW 2 5 5 , 0250 PR/ NT AT 1 4 . 1 . I NK 1 J "ALTI T

UDE"251 P RI NT AT 1 0 . 3 , I NK i i -RFI NGE

252 PRI NT AT 2 , 2J I N K WS P E E D"253 PRI NT AT 6 , 1 ) I NK l i " T A I L F

PATE '310 PLOT 8 9 , 9 5. D R A W 1 6 6 , 0. P LO

T 0,1 60, DRAW ee,o, PLOT 89,112

DRAW 1 6 6 , 03 4 0 FO P t = 3 2 TO 1 2 8 S TE P 1 8 P L

OT 0 , t DRAW 8 6 , 0, N E X T t

390 PRI NT AT 2 1 . 4 'OVER 0 C O sue

70090 PRI NT AT 17, 15, "DESTI NATI ON LAP" 520 I F s<150 AND a >0 THEN GO TO

100 LET a * 0 L E T L E T d - 0254 PRI NT AT

MENTS"0,0,

INK 3 , "I NSTRU 5000540 PRI NT AT 5 . 1 " I n c r e s s e ' D e c

LET r O L E T c •e v LE T f * 2 9. L E TrI*0

255 PRI NT ATLEFT"

1 2 , 0 , INK 1J "RLINWP r ease";AT 6 , 1 3 J " t hr us t * 7 5 / - 7 5 7 "560 I NPUT x . I F x >7 5 THEN LET v

200 OYER 1 I N K 2 P LO T 0 , 0, D PAW 2 5 5 , 0 DRAW 0 , 1 7 5

, D R A W - 2 5 5 ,0 DRAW 0 , - 1 7 5

256 PRI NT AT 1 8,0 ,

ANGLE"257 PRI NT AT 0 , 1 ;

INK 1 ; "FLAP

INK l i "R/ BEAR563 I F x < - 7 5 THEN LET x ‘ - 7 55 7 0 L E T s =s 4-1, L E T c = x L ET x =0

210 PLOT 0 , 1 6, D R A W 2 5 5 ,0 P RI N

ING" IF s ) 6 0 0 THEN LET sm600T AT 2 0 , 0 ; I NK 1," F U E L "220 PLOT 3 2 , 0 . DRAW 0 , 1 6 . PLOT

9 2,8 DRAW 223,0

250 PRI NT ATRATE"

4,0,

INK WACCE LE 572 LET s * s - 5. I F s < 0 T H EN L ET

s* 0573 LET 1 * 1 - I NT ( 1 . 2 5 * ( s t < 1 - d,- 1

230 PRI NT AT 2 0 , 4 . I N K 3 ,1 10 5 0

259 PRI NT PT 16,1. INK 1," D PO r

0 0 ) ) )0 )

1110111 MI-1M

wine&i n = 11. 2 012 1 11 1

I M I T W I l a r1135111Mr marM i n i m

• i r l• •••

0/10111

/e

f/101. " 0 1 1 1 1 1 / 1 k I O W \ \07", 1 , 1 1 0 1 " " ' ",•••• _ • - • • : - -Ana. - - • • • • • • • • • - , %

V 01 4 1 # 1 1 1 1 a l n i t e l t

, , . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

USA

...1

ggtz.172., ........K E E

EgiEl

0 .1 ,00110410 .1

AIRPLANE simulates an aero-

plane flight from London to oneof 10 airports round the world.

The screen displays your control panel,complete with information about speedand course.

S I N C L A I R U S E R A 0FIlia l 1 9 8 4

You are given the opportunity tochange your speed, height and course.If you choose not to alter any of them,enter "0 ". Keep your changes withinthe defined limits and look carefully atthe readings displayed before making a

change. You have no second chancesand a slight mistake will lead to a crash.

The program was written for the I6KSpectrum by David Courtier-Dutton ofBradfield, Berkshire.

95

96

I

losaff f f f f f f f f f f f

1 : 1 1 " 1 1 1 1 1 1 1 1 8 1 1 1 7 1 1 1 / M r a t i u t i l l i a l l i t ta t i l l i i i i i i 0 1 1 1 1 0 1 1 .J i . . • i at • • ,. . . . . . . .

1 , -

i w i r n

4113 ,,., 7)9 .6•9EllEIlal en ? • t 111 , ° - .4 / 1 ? ‘ ° I ' l j. : - : -: ' . ' .

...........1114/4777-11LIk1/4s•lI1j.

.•......••4anina

, 1 7

• • •i .

ASh

. . . . . . . . . N I J O N , . " 4 " .

14 UMW

0 1 4 10 1 1 1r

4 :411"721:111 :

IN M A N

575 CO SUB 7 0 0578 I F s<150 AND a >0 THEN CO TO5000580 LET x +0 P R I N T PT 5 , 13J"Cha

nge fl a P a ngl e ?" , AT 6 . 1 3 J " 5 0 / - 5 0" I N P U T w L E T n+n+i ) .

I F n>50 THEN LET n+5 051:11 I F n< - 5 0 THEN LET n+ - 5 0582 LET a+a+/ NT ( 3 . 0 6 * n> I F a<

-5 THEN CO TO 5 0 2 0583 I F a>u500 THEN LET 41+500585 I F a <4 ANO 1>100 THEN LET a

. 0590 LE T r m I N T ( 3 . 0 6 4 ( n ) , L E T s . s

- n595 I F a <0 AND a>m-5 THEN LET a

+0600 CO SUB 7 0 0605 LET v o. 1

618 PRI NT AT 5 , 1 3 ) " A l t e r t a i l fl ap? " ; A T 6 , 1 3 ) " + 4 5,- 4 5 " I N P U Tz. LE T d+d+z . I F Pe>179 THEN LEpam-179

612 I F P e <- 1 7 9 THEN LET Pe+179620 LET Pe+Pe-d630 I F 1 0 . 0 THEN LET w+w-s635 I F r o. e) THEN CO TO 5040640 I F a <0 AND 1 >0 THEN CO TO 5

080643 I F at<+0 AND Pe<>0 AND 1<+25

0 THEN CO TO 5108660 LET f + f - I N T ( ( I I / 1 0 + 5,2 0 ) '

e / 2 ) > I F f < = 0 THEN CO TO 5040670 I F 1>400 AND 1<500 AND a >5

AND a<50 THEN LET a • 1 0 0675 I F s>230 AND a<+0 THEN LET

a+50680 I F w<+0 THEN GO TO 5060

700 PRI NT AT 3 , 1 ) I NK 0 ) s , " " JAT 1 5 , 1 ) a J " " , A T 1 1 . 1 ) 1 ) " " ) A T7 , 1 J d, " " ) A T 1 9 , 1 ) 6 ) " " J A I 5 ,

l i e ) " " J A I 1 7 , 1 ; r ) " " J A I 9 , 1 ) Pe ) " " J A T 1 3 . 1 ) w ) "810 FOR tm16 TO 144 STEP 1 6 . P L

UT 13, t DRAW 8 6 , 0 NE X T te60 PRI NT AT 8 , 1 2 ) I NK 4 J " -

R/REARING • "880 PRI NT AT 9 , 1 2 ) "

890 PRI NT AT 9 , 2 1 ) " o ", P R I N T A T9 , 2 1 - I NT ( P e e 2 0 ) ) "^ "892 I F z x<>O THEN GO TO 900895 RETURNSOO PLOT I NK OJI NT ( ( m - 1 ) / 5 0 ) + 8

9 , I NT a / 1 8 +1 4 6905 LET z x o0910 PRI NT AT 2 1 , f ) "920 I F a <+0 AND w>+0 AND f > 0 RN

0 P e - 0 AND 1 ( 0 AND ' 0 . 0 AND 8 . > -1 THEN GO TO 6000

935 I F a<+40 THEN PRI NT AT 1 6 , 1Si I NK 2 ) PAPER 7 ; FLASH 1J"ALTITUDE"

940 I F s<165 THEN PRI NT AT 1 4 . 13; I N K 2 ; PAPER 7J FLASH 1. "SPEE0"

943 I F W O O THEN PRI NT AT 1 2 , 15) I N K 2 ) PAPER 7 , FLASH 1J"RANCE"

950 I F 1<300 AND P e <) 0 THEN PRINT AT 13, 15J I N K 2 ) PAPER 7 ; FLASH 1J"RAI EAPI NC"

955 I F w<200 THEN PRI NT AT 1 2 , 15, I NK 2 . PAPER 7 ) FLASH 1;"RUNWAY LEFT"

960 FOR 4+1 TO 100 . BEEP . 0 0 7 , -22 N E X T 4, F L A SH 0 . P RI NT AT 12

, 15J" " ) F I T 1 3 , 1 5 ) "")FIT 1 4 , 1 5 ) "

";AT 1 3 . 1 5 ; " jAT 1 6 , 1 3 J "1000 CO TO 5 0 01020 PAPER O. I N K 5, B O RD E R 2. C

LS1030 PRI NT AT 10, 10)"I NSTRUCTI ONS? E y / - 0 "1035 I F I NKEYe. "n" THEN PETupt.41036 I F I NKEYS+"" THEN CO TO 1 0 35-

1037 CLS1040 BEEP B E E P . 3 , 0 - BEEF.3 , 0. BEEP .8,-5

1050 BEEP . 3 , 3. B E E P .3 , 3. B E E F-.

.3 , 3 . BEEP . 8,- 21060 FOR m+-7 TO 5 BE E P • 1 . m NEXT m P AUS E 2 0 BE E P . 1 7 , 1 5 P AUSE 1 5 BE E P . 4 , - 2 5

1070 PRI NT AT 1 0 , 1 2 , I NK 2J"RI RPLANE"- P AU SE 150. CLS

1080 PRI NT " AIRPLANE s i m ul s t e san a i r o P l a n e fl i g h t f r om London ai r P or t t o o n e o f t e r o t he r a i rPor ts a r oundt he w or l d, t he c hoi c e

of w hi c h i syour s . However fl y i n gA P l a n e I s n o t a s e a s y a s s ot t

ss t h i n k . s o r e a d t h e s e i n s t r u c t ions c a r e f u l l y "1108 PRI NT ' ' ' . " " , FLASHPRESS ANY KEY TO CONTINUE"1120 I F I NKEY0+"" THEN GO TO 1 1 2

1130 CLS . P RI NT , FLASH 1, "BERRIN MI ND"; FLASH 0 ) ' " Y ou w i l l a t

a l l a t unde r 1 3 0 KMH s o do n o t teke o f f be f or e t h i s s p e e d i s a tta i ned"

1140 PRI NT ' " T o change a l t i t u d ea P os i t i v e ( u P ) o r ne ga t i v e ( down) v s l ue m u s t be a P P l i e d t othe fl a p s . y o u r a l t i t u d e w i l lchange by t h r e e t i m e s t h e fl sP a n g l e "1150 PRI NT ' " T o a l t e r c our s e useYour T A I L F L A P , w h e n t he r unwa

y be a r i ng E R / B E A R I N C 3 i s 0 weu w i l l b e on"1155 PRI NT " c our s e . I n t h e R/BEARING di s P l a y y our de s t i na t i on i sr epr esented 169 ' o ' a n d y our • c t ual c our s e by "1158 PRI NT " ' ' ' ; w h e n t h e ' o d i ssaPPears y ouw i l l b e o n ,: o u r s e ! . '


i o, •

•

.. . . . . 0 , • • • • • • o v i s i l fi l A W N O l i ,

ondi •••.

7 01 11E1 11 r:'1.;k-*-Z°

1111! MVV6.4.11144 WIII111111101111111110111111rnitimtuntoutuatio,....-

rsl imu l lmuNkmiumis t fu luma l i l i bmai to , -

I I . . . . . . . . . . . . 4 1 01 1 1 1 1 1 . 11

. . . . ". . ". . . 1 1 1 41 1 1 0 11 1 1 1 . 11

. . . . . . • 1•111,••

M i t t

?PI

1162 P R I N T F L A S H l o " P RESS ANY KEY TO CO NTI NUE "1170 I F INKEY111."• THE N GO TO 1 1 701180 CLS P R I N T " Y o u r s p e e d w i l1 d e c r e a s e a s Y o u c l i m b a n d i n c rease a s J o u doc e ndD ue t o s i r r e s1 s ta nc e A t w i l l d e c r e a s e bw 5KMH a f t e r e v e r y s e t o f i n s t r u ct i o n s "1190 P R I N T ' " T h e RUNWAY LE FT r e f• r s t o y o u r d e s t i n a t i o n a n d i ft h i s v a l u e 1 a l e 5 s t h a n 0 y o u - w i l1 c r a s h . "1200 P R I NT ' " Y o u r P o s i t i o n r e l a ti v e t o Londona nd y o u r d e s t i n a t i on i s P l a t e d a t t h e t o P o f t h e sceen t o s how y o u r P o s i t i o n a t a9 1 a nc e . 1 he d i s t a n c e y o u a r e f rOM V O W' d e s t i n a t i o n i s s how 'n i n t h e R A N G E r e a d o u t "

1220 P R I N T i ' ' " " . FLA S H 1 ; " PRESS ANY KE Y TO CO NTI NUE "1230 I F INKEY111."" THE N GO TO 1 2 301235 CLS , P R I N T " T o l a n d s uc c e ss f u l l w O u r s P e e d m us t e q u a l 0 , your a l t i t u d e m us t e l u a l 0 ; a n d w ou MUS T b e o r t h e r u n w a w "1240 P R I NT ' " F l a s h i n g i n s t r u c t i ons w i l l h e l P w ou t o fl y t h e P l a ne s a f e l y . G O O D LUCK! "1250 P R I N T ; I N K 6 . ; " " T O REPEAT

INSTRUCTIONS PRESS ' R P R E S S ANY OTHER KE Y TO BE G I N"127e I F I N K E Y S . " r " THE N CLS • G O

TO 1 0 8 01280 I F I NKE Y 1 1 . "" THE N GO TO 1 2 7

4000 PETUPN

5000 PAUSE 4 0 C L S P R I N T " Y o us t a l l e d a t " ; 1 1 , " K / M / H a n dr a s he d -US E LE S S " G O TO 5 2 0 0

,51Na_AIR USER ,4ptnual 1984••• • • • • 1 .

5 0 2 0 PAUSE 4 0 C L S P R I N T " Y ou, -a l t i t u d e i s " J a i " m e t e r s s o y o u

ha v e c r a s h e d -US E LE S S ", G O T O 5

2 0 05 0 4 0 PAUSE 4 0 C L S P R I N T " Y o ur a n o u t o f f u e l s o w ou h a v e c r as he d-US E LE S S ", G O T O 5 2 0 0

5 0 6 0 PAUSE 4 0. C L S . P R I NT " Yo u

ov e r s h o t t h e r unw a w bi t ' A B S w ;" m e t e r s s o y o u h a v e c r a s h e d - USELESS"' G O TO 5 2 0 05 0 8 0 PAUSE 4 0, C L S P R I NT " Yo u

t r i e d t o l a n d " 1 1 , " m i l e s s h o r to f t h e r u n w a y s o WOV h a v e c ra s he d-US E LE S S ", G O T O 5 2 0 0

n e e PAUSE 4 0 C L S P R I N T " Y o uha v e m l s s e d t h e r unw aw c o m P l e t e ly bw " J P e , " d e 9 r e e s a n d h a v e c r as hod -US E LE S S " G O TO 5 2 0 05 2 0 0 PAUSE 3 0 0 C L S , P R I N T " A n ot h e r fl i 9 h t 7 ( w / n ) " ' I F I NKE Y S . "s i" THE N GO TO 1- S T O P5 3 0 0 CO TO 16 0 0 0 LE T k e I N T f / 36 0 9 2 L E T- -s c . I N T < I 1 0V w /t r ) ). LE

I k . ( 2 * 1 0 . s c6 1 0 0 PAUSE 1 0 0 ' C L S P R I N T " W e l1 d o n e4Y o u I c or ed "JINT kJ" Poin

t s o u t , o f a P o s s i b l e 1 0 0 " ' S TO P° l e e STO P9 5 0 0 I N K 7 ' BO PDEP 2 ' P AP E R 0, CLS P R I N T "W HI C4 AI RP O RT7 " ' P R INT " 0 ) I s t a n b u l " ' " I ) C h i c a c o o " ' " 2 ) Mi l a n " ' " 3 ) M o s c o w " ' " 4 > N e w Y o r k " ' " 5W a r t S t a n l e s o " ' " 6 ) 0 s l o " ' " 7 Y I e l Av i v " ' " 1 3 ) O e l h i "." 9 > T o r o n t o "9 5 0 5 I N K 2 ' P AP E R 79 5 1 0 I F INKEY111."1" THE N CO TO 9 6009 5 2 0 I F I N K E Y S . " 2 " THE N GO TO 9 62 09 5 3 0 I F I N K E Y S . " 3 " THE N GO TO 9 64 09 5 4 0 I F I N K E Y O . " 4 " THE N CO TO 9 6

9 5 5 0 I F I 4 KE Y 1 1 . "5 " Ti -4: A TO 9 68 09 5 6 0 f r I N K E Y . . " 6 " THE N GO TO 9 7009 5 6 5 I F T w u s - o e - THE N CO TO 9 7209 5 7 0 I F I N K E Y S . " 7 " THE N CO TO 9 740957.5 I F I NKE Y 4 1 . "8 " THE N GO TO 9 7SO9 5 8 0 I F I N K E Y 1 . " 9 " THE N CO TO 9 78 09 5 e 5 GO TO 9 5 1 09 6 0 0 CLS L E T 1 . 4 2 3 5 L E T e e 1 5

LET w . 7 0 0 L E T P t7 . 1 7 0 P R I N T A T1 8 , 1 6 ;"CHI CAG O " R E T U R N

9 6 2 0 CLS L E T 1 . 5 8 1 ' L E T e . 4 LET w e 7 0 0 L E T P e = 3 5, P R I N T A T l e

,16J"MILAN"' RETURN

9 6 4 0 CLS , L E T 1 . 1 5 4 9, L E T o e 9LET w . 6 4 0 L E T r e . - 1 0 • P R I N T P T1 8 . 1 6," M O SC O 4 " R ET UR N

9 6 6 0 CLS L E T 1 - 3 5 0 0 L E T s . 1-1

LET w . 7 5 n L E T P t ! - - i 7 0 P R I N T AleAci-NEw yoRK- RETURN9 6 8 0 CLS L E T 1 . 7 4 0 6 L E T P . . aA

LET w . 4 4 0 L E T P e -,1 1 0 ' P R I N T A

T 1 0 . 1 6 i " P O P T S TANLE Y " ' P E TUP N9 7 0 0 CLS L E T 1 . 7 2 2 L E T . -LET w e 3 0 0, L E T P e e- 3 0 P RI NT A7

1 8 , 1 6 "O S LO " R E T U R N

9 7 2 0 CLS L E T 1 . 1 5 6 2 L E TLET w . 4 8 0 ' L E T P e . 3 5 P R I N T A T

1 8 ; 1 6 " I S T A N B U L " ' RE TURN

9 7 4 0 CLS L E T 1 . 2 2 3 0 L E T e e l lLET w . 6 5 0 L E T P 0 . 4 0 P R I N T A T

1 8 . 1 6 J "TE L A V I V ", P E T U P N9 7 6 0 CLS L E T 1 . 5 2 0 3 L E T e . 1 8

LET w . 5 1 0 L E T P e . 3 4 . P R I N T A T1 8 , 1 6 , " D E L H I " ' RE TURN

9 7 8 0 CLS L E T 1 . 3 7 2 1 2 . L E T e . 1 4LET w . 5 5 0 L E T P e • - I.5 0 P R I N T

AT 1 8 . 1 6 i " TO P oN TO " R E T U P N

97

The Fuller gift pack has got to be thecomputer bargain of the decade, no wondereveryone wants to get their hands on one_

This super gift pack contain the lantastkFuller Master Unit the ultimate unit thatprovides all the requirements for the seriousgames enthusiast The Fuller Master UnitIncorporates both the Fuller Box and Orator, itsamazing features include a speech synthesiser,an independent sound synthesiser, a joystickinterface, an amplifier for standard Spectrumsound, a cassette interlace and a hi -if socketThe pack will also include a Master Unit demotape and full documentation

As well as the Master Unit this Gift Pack alsocontains a de luxe Joystick. with suctionadhesion, a firm smooth action and a mouldedhand grip incorporating twin firing buttons..

Once your Spectrum has been added to theFuller Gift Pack you will have an extendedcomputer system that is second to none

Now you can pit your mind against the fourunique, exciting computer games included inthe pack_ These games have been especiallyadapted for this superb system and have addedarcade sound effects and speech to bring outthe very best in your Spectrum

The Fuller Gift Pack savesyou E20 on the purchaseprice of buying these Itemsseparately

• 9WHIM, a lp /S W

Power to your Fmgertips;-

AH keys onthe FOS keyboardcontain all theGtaphic Charactersal the IX Spectrum

Transform your Spectrum with the PDSKeyboard and feel the newly acquired powerflow from your fingertips as you enter data withlightning fast accuracy. The Fuller FDS Keyboard has been especiallydesigned for the professional user This elegant.slim line, desk top system has a keyboard thatinclines toward you and contains all the graphiccharacters of the IX Spectrum, plus, additionalfunction keys, shift keys on either side and aspace bar With all the entry keys double size.lightning fast, accurate data entry is now madeeasy. Other amazing teatures of the FOSinclude:-Gold plated key switch contacts, guaranteed for106 operations. 4 cursor control keys, 2 functions

for direct entry into E mode.- ' —Based on the popular FE142 system. the Fuller

EDS is simple to install. it reoures no solderingor technical knowledge For the user who isreluctant to install his computer circuit boardinside the FOS, a buffer is available ti8.75 +80p6p) which simply plugs

into the expansion portand connects directlyto the keyboard

,

Microdow mietiace Ieasily adaptedto hi muter--the case

Fuller Micro SystemsThe ZX Centre, 71 Dale Street,Liverpool 2_ Tel: 051-236 6109.

Al fullerMinn systems

Yet %Uwe tomaintain the

hiuhest qualityin both research anddeirkwirtwni ensutinu

ow product% ate the sirevtwit Mgr haw now built a

bland tn.,* M a i l o l de r

departnwnt lo rnsulr ow senneeis also i hr yety best Ow stock

includes a hill ua n c r o f ,( o m p o ne n t $

and kin that will make the most ot youikpeeti um a ll i i p i u, iu t t l , e n v o y a m

cm-cl ie nt imputat ion lot reliability and

calm a world wide one yeai gum anlee

Card No

SignatureNameAddress

I I I I I I 1 I I 1 I I I I I I

Fuller Micro Systems. The ZX Centre,71 Dale Street. Liverpool 2. re! 051-236 Olog

Please cupply me withI enclose a cheque POpayable toFuller Micro Systems for o r debit my credit card.

FDS KeyboardislFuller Gift Packis)

11BarclaycardDAccess Card

yOU ARE a forester, moving

around th e forest, shooting-down the dead trees. A robot is

chasing you and wi l l ki l l you i f hecatches you. Whenever you destroy atree several carnivorous trees w i l lspring up in its place and they will killyou i f you shoot them. Move yourselfwith I, .1, K and M and direct your gunwith A, W, S and Z.

Robot H u n t was written fo r theSpectrum by S Hirst o f Hull, NorthHumberside.

U.;tf LET L E T ID..v140 LET 34. . INKEY* I F all..."u" ORalliv"s" OR a l w"4" OR W W 2 " THENGO TO 150143 C*0 SUB 400145 CO TO 100150 I F 1 $ - "a " THEN GO TO 200I t t I F a * - " s " THEN GO TO 250ICO i r a $ " THEN CO TU 3001E5 I T a 0 P-" z "

THEN GO TO 3.50170 LET f..0 TO 180

1 REM * 4 F-L . L _ - . ; H U N T * *

3 LET nscr w04 LET hi t ' . 0t LET man. .5- L E T m *,. . " c c cc c "

10 LET L E T v . 1 0 L E T a. .15 L E T b•1 0

11 LET s c r,4 3 L E T m o .. 0

15 BORDER t17 f -LS20 PRIN1 AT 0 , 0 , "c c c c c ROBOT

HUNT s c r - 00000".Z0 FOR 1..1 TO 20. BEEP .1,RND*

3031 LET tv=RND*20+1 L E T tx0RND

*31 I F ATTR ( t w , t x ) 0 5 6 THEN GOTo 51

P9INT nT t w , t x ; I NK 4J"1"

NEXT 10•11P 3t CO TO 55

50 FOR 2. .1 TO 21. BEEP . 1 , RND*30

51 LET tv-RND*20.4.1• LE T tx•RNV* 31. IF ATTR (tv,tx)<>56 THEN CO

TO 5152 PRI NT AT t w A x ; I NK 4 , " i " .

NEXT 1t t LET tIots.-.0CO LET h- I NT (RND* 20)+1. LE T 1

mIHT (RNVV31). I r ATTR ( M ) < > 5 6THEN LO TO 8 0GI L.:A' hz - h. L E T I t - 1. L ET m o. ..

002 r ' I N T AT h, 1 4 " ' ART hi , 1 1 J "

AT nT 0 , 27J"(5* 1sP' . ", AT0 , --, 1,scr

99 REM m a n c ont r ol100 LET x-x-0-(INKEY* . . . "k")* (x<31)

- ( I NKE Y S . ' "o" ) V x :,( 1 )

110 LET w v 1 . 4 4 . ( I N K E Y S,. . " m " ) * ( w ( 2 1.)

- ( I N K E Y l i m " 2 " :,U 1 C - 1,

113 I F ATTR ( v , x > - 5 8 THEN LET hlt&513 L E T 4. .,4* L E T 1 1 .,1 1. G O TO 5

30I l t I F A T M ( v , x ) 5 6 THEN LET

*ma L E T w.ka120 PRI NT AT/23 I F x ( s THEN PRI NT AT b.4* *"

", AT w.x;"1;1" BE E P . 0 5 , 2 3 P RI NTAT w , x ; " * " BE E P . 0 5 , 1 0125 I F 751 THEN PRI NT AT l o, a, "

BEEP . 0 5 , 2 3 P RI NTAT t o, , WW:. B E E P .0 5 ,1 0

130 I F lo<>ko THEN PRI NT AT b , a ) "";AT d, x ; : f . : . BEEP . 0 5 , 2 3 . P RI N

T AT * * , x " BE E P . 0 5 , 1 0

199 REM s h o o t•••1111L

SINCLAIR USER Ai inual 1984

100

. 0 1 , - 5 F U R 1-1 . T O )( -

I F • ; T H E N P RI NT A TNEXT t • F U R 1 .-. 1 T U x

nT . - NE X T t. G O

h a - A T T R ( w p x - 1 )7JR T U P R I N T A T w ,

". N E X T nLET L E T x l x xGO TO 5 0 0

250 LEEP . 0 1 , - 5 • r o R I - 1 T O 3 1 -x. IF ATTR (si,x4.1)..5(, THEN PRINT

AT w , x . l , " - • N E X T 1 . F U R t . 1 T0 2. 1-x- P R IN T AT w .x 4- 1. " * NEXT

Cu TO 10025.: LET hit-ATTR <m.x+i>

2 t t FUR n. .1 TO s - I P R I N T AT v ,x+n, " ' N E X T h

25e LET ml .m• LE T x iuo TO 500dammt300 DEEP r u Rt I F ATTR

AT m -1". N EX T 1

w-1 P R I N T AT• GO TO 10030-. ; LLT hit-ATTR <w-

e-7, FUR o-1 TO 1-1

" N E X T A3oe L T ml -m-t • LE T310 T O 500350 SEEP . 0 1 . - 5 F O R 1 . 1 TO 2 1 -

w I F ATTR ‹ w + , O x 5 6 THEN P RI NTAT v . . . i , x , 1 " N E X T i F U R t . 1 T

0 2 1 -1 P R I N T AT . . . . 1 . x ; " - NE X TGO TO 100

352 LET h i t A T T R ( v . t . x )355 FOR o..1 TO 1 - 1 • PRI NT AT

NEXT n35B LET wl.v.01 L E T x l • x3C0 GO TO 500399 REM P I C M I A420 PRI NT I NK l i AT h , t ; ".1 2 : , A T

s,11; I NK 0 , "422 BEEP . 0 1 , 0425 LET h l . h L E T 11 . 1

•C..s

1.1 TO m-1THEN PRI NTFOR 1 . 1 TO

NEXT 1

I , x )PRINT AT w -

-x l . x

430 LET h . h . ( h < w ),I N T ( R N D * 2 ) - (

h>v ) - I NT ( RND* 2 ). I F h > 2 1 T H E N L

ET hmhi433 I F h<1 THEN LET425 I F ATTR ( 1 , 1 ) <>5 6 THEN LET

1.1.14.11440•LE1 1•1- . <1<x)+I NT <RND* 21-t

1>x) - I NT 0 1 1.( 4 2 ) . i r 1 > 31 T HE N L

ET l m i t445 I F ATTR ( h , t ) - 0 5 6 THEN LET

450 I F h...w AND I mx THEN GO TO 1

7 :e RETURN

0 •P RI NT A T O V E R I ' " C i s

4c499 REM * x P l o s i o n

p r B E E P . 2 , - 2 0 P R I N T OVER L A1-MI'x1,*(9I)" BEEP PRIN

T OVER 1JAT m 1 . x 1 < 9 2 > " BE E P .1.4 P R I N T OVEP 1 ; A T-W-, x 1 J " ( 1 9 7

>" BE E P . 1 , 4 5 P RI NT AT w l , T f 7DEEr . 1 , 1 5 P R I N T AT w l . xr7-

-0 DEEP

: h i t - 5 7 THEN LET scr si cr 4-20 G O TO 0 0

SIO L T z . c r-s c r x t .

t 9 t 1 .-t e i t s- 0 - 1 IF t .. ..1 .7 .1 9

THI N .4.1 TO ' A520 n x 1 TO 4522 LET t i o-R N L 4 2 0 4 -1. L ET t x -R N O

*J1 / 7 RTTR ( t v , t x ) . . 6 0 THEN GOTO 5 2 2

5 . 4 P RI NT A l t i o , t x . / N C 2 J '1 1 : .NEXT n530 I F h t t - 5 0 THE N P RI NT A T v , x

; O V E R 1 , " ( 1 0 ) " . S E E P . 2 , - 2 0, PRINT OVER t A I T t o,m , " . c e j > "- B E E P

. 1 , 3 8 P RI NT OVER I t AT w , x , " ( g2 )" DE E P . 1 , 4 P R I N T OVER I ; AT w,x, "<1.27)" BE E P . 1 , 4 5 . PRI NT AT

BEEP .4,15._JORINT ATWeXI 77.7 BE E P . 4 . - 1 5- G O T O 1 0 1

h i m . P5 4 0 G O TO JO

999 REM 9 o l n i a t o s o b b t •1000 P RI NT AT h i , I 1 ; " " ; A T h , l i

PLASH 1 , 1 2 : B E E P 2 , - 2 5 P R I N T Ah, l ; FLASH 0 , I NX O i "

101A7.'i o P % N 7 AT 0 , 0 , ". . . 2 t l E t ) ";AT0,00/1 TO man4.2>

1025 1r hlt-ta niNt man0 THEN LEI h t t-.1 U O OU TO 913

10?0 i r maf,A) THEN GO TO 002000 REM c - n d o f game2020 7OR L,1 0 T O 2 0 F OR n .. 5 TO

eEz7 . 0 2 , n. NEXT n NE X T i2027-, 17 fic r7,hsc r THEN LET hscr...*

CrLI A P R I N T A T 1 0 , 0 ; FLAS H

1 . * * * CAME OVER X* "2040 P 2 I N T A T 0,2 1," 1 4 c o r e m * As c r ;

AT 0 , 0 ; "h1 9 h s c or e . " . hs c r2000 P RI NT A T 2 1 , 2 , P AP E R E . "P RESS ANY KE Y TO P LAY AG AI N '2 0 0 PRUSE 020C12 ELS GO TO 4

9 0 2 0 R EST O R E 9 0 7 0 F U R m x I T O 1 0. -9030 REAL. PS

80443 r oR rt...0 TO 79010 READ a POKE USRwacia NEXT n- N E X T m G O TO 1

9070 DATA "1".24,2ce.lsolo ,z4,36 1 , 290U0 DATA " G ",2 4,2 4 , 1 3 , 2 4 ,4 4 , 8 , 0 ,

9090 DATA " c ",8 . 1 3 , 8 , 2 9,4 2 , 0 , 2 1 1 ,2

9100 DATA " d ",2 4 . 2 4 , I 6 , 60 , 8 0 , 2 4 .

100,49110 DATA " 0 ",2 4,2 4,1 6,2 4 , 5 2 , 1 6 ,

16, 169120 DATA " f ",0,0,0 , 3 0 , 4 0 , 24 , 2 0 ,

49E40 DATA " g ",0,0 J U,6 0 • 1 0 , 1 2 ,2 0 ,

169140 DATA " h 2 4,1 2 6 , 1 5 2 , 2 55 , 6 0 .

126, 90, 219915C " t " . 1 6,0 4 , 4 1 , 1 70 , 9 3 . 1 7

0 , 9 C . 2 491E0 orrrn, 1C, 16

yOU ARE the ravenous toad-eat-

ing crocodile at the bottom o fthe screen. Press 'P ' to fire a

venom blast which will gulp down oneof those tasty toads passing overhead.The Society fo r th e Protection o fToads, which objects to the wholesale

slaughter, has erected a forcefield.Firing while a toad is behind i t wi l lresult i n al l the frogs escaping, thusending the game_

Tasty Toads was written for the 1KZX-81 by Andrew Brewster of Roches-ter, Kent.

TASTYTOADS

REM2 L E T C . 03 L E T A. . 04 RAND5 FO R A4 1 T O 56 CLS

10 LET Aml e20 LE T F. . 2 * ( I NT ( RND* 0 ) )30 FOR 8. . 0 TO 2 035 P RI NT AT 6,0," * * * * * * * ** F O R C

E * FI E LD* * * * * * * * * * * * "40 PRI NT P T I 9,1 5 ; " ( i . g 6 . 1 .) "

,AT 1 6 1 ,14; " ( g w .3 * s P,g t ) " J AT F,BJ

" ( 1 . . 9 6 1 . ) " J AT F. . 1 • BJ " ( gt 1 - gv)"

50 I F M<F THEN LET M.11360 I F I N K E Y W P " OR 1.1.(18 THEN

PRINT PT M,1 6 , . "

65 I F 0 . 1 5 AHD M. F THEN GOTO 150

70 I F I NKEYS. "P" OR M. (18 THENGOSUB 1 2 0

00 PRI NT AT R, B; " "90 NEXT B

100 NEXT A120 PRI NT AT M . 1 6 " "125 LE T 11.01-2130 RETURN150 PRI NT AT M, B, " gut?. " J AT m.

160 PAUSE 5 0170 NEXT A

SINCLAIR ITSER An'i mu 1984

pENTALPHA is a version of an

ancient Egyptian solitaire gamewhich L Gabb of Northfield, Bir-

mingham has converted for use on the16K ZX-81. The aim is to enter thenine counters on the 10 points o f apentagram. A piece may be entered onany unoccupied point and must then bemoved two points in a straight line toanother unoccupied point.

The intervening point may be occu-pied or unoccupied. I f no more movesare possible before all the counters havebeen placed, the game is lost. Movesshould be entered by pressing the lettercorresponding to the point where youwish to enter your counter, followed bythe letter corresponding to the point towhich you wish to move it.

1U D I N P ( 1 0 :,- 0 L E T J W I L E H 8 D J F A G I L.JO L L S

100 P RI NT A T 0 . 0 ) " * P e r i t a l P h a t " ,TAB 1 5 ) " a " J T A 0 1 4 . . " ) T A B 1 3 . "

f t

120 P RI NT TA B 6 / " 0

130 P RI NT TA B 9 ) " . .140 P RI NT TA B 1 0 J " 4 .150 P RI NT TA B 9 .160 P RI NT TA B 8 1 .

170 P RI NT TA S 7 ) " .

180 P RI NT TA B 6 ) " 1 . " ) T A B 2 3 . " _

190 P RI NT230 P RI NT TA B 6 1 "m o v e • n t o r n o v

• t o "500 FUR M.,1 T O 9

505 FO R I h 2 TO L E N J O - Ib a t I F NO T (PNCODE . 1 0 ( 1 ) - 3 7 1 UR(P(CODE J 0 ( 1 - 11- 3 7 ) A N D P ( L O DE

JO(I + 1 ) - 3 7 ) ) ) THE N GUT() 5 9 0520 NE X T I530 P RI NT A T 1 4 + M A I W Y 0 0 LANNUTMOVE A ND HAVE FA I L E D "540 UOTO 9 1 0600 L E T A S - "610 L E T B S --620 P RI NT A T 1 2 4 4 4 , 1 1 ) "

630 P RI NT A T 1 2 + 1 4 ) 7 M ) TA B 1.3," 7

640 L E T A 0h I NK E Y 0650 I F A I W A " O R A S > " J " THE N GO

TO 6 4 0660 P RI NT A T 1 2 4 . h . 1 3 )A S670 I F P (L UDE A S - ? ) THE N GLTO

1001680 UUSUB 1 5 0 0605 L E T A . X6e6 L E T b . "Y690 P RI NT A T 1 1 ) 8 J "0 "740 P RI NT A T 1 24 ,M , 2 0 " 7 "730 LET 8111.-INKEYS740 I F e l K " A " OR B I W J " THEN GO

TO 7 3 0750 P R I NT A T 1 2 4 . M . 2 0 8 0760 I F P (LO DE 0 0 - J 7 ) THE N UUTU

1001770 Fu R 1 2 TO 1 1780 i F A S . J 0 ( I ) AND EMK>J111<1-1AND 130<>J 41(1 . 1 ) THE N 6051)8 1 0 0 3790 NE X T I795 L E T P(CO DE 8 0 - 3 7 ) . 1600 UOSUB 1 5 0 0610 P RI NT A T A . B ; L H R I (L UDE A S .12e)JoT X,Y"U"020 NEXT M900 P RI NT A T 1 , 0 i " : 4 4 E L L Uu NE <"910 P RI NT A T 0 . 1 3 J " P r e s s r t o r

u n " i TA U 1 9 " o r s t o s t o p "920 L E T RehI NKEYS9 j 0 I F A W R " THE N RUN940 I F A W S " THE N STOP950 UOTO 9 2 0

1000 L E T P (Cu DE A 0 - 3 7 ) . 01001 P R I N T A T 1 2 4 - h . 1 1 ) " I N V A L I DOVE")AT A . 8 J L H R 0 ((. O DE 1104.128)ND 8 4 v > " "1002 r o R 1 . ' 1 T O 5 01002 NE X T1010 r..UTO 5 0 51500 I F O W " THE N L E T Ti lwA 01510 I F 0 0 < > " " THE N L E T TO•1301520 I F T W A " THE N L E T )0 . 01530 I F T 0 > " A " A ND T O ‹ " F " THE N LET X ". 31540 I F T W F " U R Te m "G " THE N L EI X . 51550 I F TtI m "H" THE N LE T ) m 71560 I F T e . " I " O R T e . " J " THE N LEI X v 91570 I F Ti l l="O" O R T• . . " H " THE N L EI Y . 1 51500 I F T e . " U " O R TO . . "1 " THE N LEI V-'-6

159e I F T i l f r." L ' T H E N L E T Y h1 2

1600 I F T W O " THE N L E T Y h I S1610 I F T i l l . " E " O R T W J " THE N L EI" Y . 2 41620 i r T H E N L E T Y . 1 0I 6 J 8 I F T S - " U " THE N L E T Y h 2 01 1 ' RETUFN

SINCLAIR USER Annual 1984 1 0 1

102

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yOUR QUEST begins as you find

yourself in the dark on the firstfloor o f a fifteen-level tower.

Your ultimate goal is to climb the towerand find the Great Jewel o f Light. Onthe way you must find keys, armour andmany other objects which are essentialto your progress.

Opposition is in the form o f weirdand wonderful creatures which appearfrom the gloom and which must bedestroyed. With luck you will climb thetower, find the jewel and find the ringwhich tells you how to leave the tower.You may even be helped by the GreatWizard.

Enter " IN FO" to obtain a completevocabulary l i s t, including th e codenumbers o f certain vital objects. Com-mands should b e entered w h e n"NEXT?" is displayed. To use an ob-ject, enter its code number.

The program was written for the I6KZX-8I b y Colin Hunniford o f Berk-hamsted, Hens, and is the first adven-ture game to be published in SinclairUser. We hope that, as well as providingenjoyment, it will also provide hints andinspiration for those interested in writ-ing adventure games. ,

• • •........ - • •• ••...• • • • •• • • •

. . • .• • • • •. .• •• • •• •• - ••

• • • • • • •.•••• •-•• •..... .•• :-:- -.

y . . . . . . . . . ▪ .•

...• . - t••••, . • • • t- - .•••-• • Y.:y.-. 0 m m . a • . • • e. . • •

• I I E M I R I O l ir . • ••••:•::::i. : .

1 .1 .111

• • • • • • • ••••••••10. • • • . . . I t . . ., . . , . ., 0,

. .--rioNNENN'1"

r t WIMP

1 RE M MMMMMMMMMMMMMMMMMMMMMmmMMMMMMMMM146 charactor-.tMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM

2 LET Aa. "200C401186021906207EC680772310F92A0C401121e0/ 9Ems0C4001D602EDBO"

3 LET Re. ROW2121032239402A0C40111960219220E40C9"

4 LET A S . A *4- " 2 1 1 0 C 4 00 6 1 5 C 5 0 62 0

2 3 7 E C 6 8 0.7 7 1 0 F 9 2 3C 1 1 0 F 2 C 9"

5 LET RI . A6+2R0C400615C5062023368010F823C110F4C9"

6 LET R 1 1 . 8 64. " 2 R 0 C 4 0 11 0 E 0 0 1 9 3 6

002336341120001936032336802396031120001936801120001936062323368661

7 LET A S . A 0 +1 12 A 0 C 4 0 1 1 0E 0 0 1 9 3 6

86112100193600C3D940"8 LET C. 1 6 5 1 39 FAST

10 FOR I . 1 TO LEN A l STEP 211 LE T C. C. 112 POKE C,163. (CODE AS < I ) - 2 8 ) +C

ODE A0(141)-26114 NEXT I15 DI M R e ( 1 5 , 6 , 6 )16 SLOW20 RAND25 LE T DO. CHRI30 DI M E ‹ 1 4 )40 LE T E ( 1 ) . 9 9 9 950 LE T C. 1 6 5 1 460 LE T T . 0

GOTO 1 3 090 LET P - I NT (RND* 6 )+1

100 LE T B . I NT (RNDS6)+1110 I F RI E N, A. B) <KHRS 0 THEN G

OTO 9 0120 RETURN130 I F USR 1 6 5 8 3 0 US R C THEN PP

INT "WELCOME TO . " ) TAB USR CJ"MURKY ADVENTURE 2,P H O E N 1 X T O W E R" , T

AB USR CJTAB USR CJ"YOU ARE RBOUT TO ENTER THE TOWER")TR8 USR C."I N WHICH YOU MUST FI ND A VEY. ")TAB USR Ci "A •EWEL. A TORCH AND MANY OTHER"JTRI9 USR C)"THINCS. TOSURVIVE."JTAB USP CJ"WOULD YOU LIKE I NSTUCTI ONS7";

140 I NPUT Be150 PRI NT " "JBMI TAB USR CI TA8

USR C)160 I F 19111.' T H E N COTO I SO170 I F 8 0 ( 1 ) . " Y " THEN GOSUB 1 8 5180 GOTO 2 2 e185 P RI NT "YOUR TASK I S TO GET

THE GREAT"JTAB USR CJ"JEWEL FROMTHE PHOENIX THAT"JTAB USR CJ "LI

YES ON THE 15TH FLOOR"JTRB USR Ci"WHEN ne w t . 1 I S DISPLAYED.ENTER" TAP USR C. "THE WORD OP NUMBEP YOU WANT TO " ' TAB USR CJ"USE. YOU WI LL LEARN THE PULES OF" TABUSR Cs "THE CAME AS YOU PLAY. " TA• USR CJ"clood l uc k "

190 PRI NT TAB USR C. TAB USR C . "WORDS MOVE.HELP.BASH,UP,DOWN.";TAB LISP CJ"TRKE•DROP. I NFO. SAVE. SNEEZE. ":TAB USP C A B OSP CJ "1 . S TRENGH"."2.TREASURE"

195 PRI NT TAB USR CJ"3. JEWEL". "4-SPELL BOOV"JTAP OSP"6.SWORD";TAB USP C J " 7 . R I N C "," 8 .,

LI GHT":TAB OSP C," 9 . S H T E L D ". " 1 0 .

WRTER"JTAB LISP C. "1 1 WAND" Ton USR c ; 1 3 . ppm oup" "14•-CLUB". TA8SR C;TAB OSR C

196 P RI NT "PRESS A KEY AND WRI T

200210PPr220240250260270280290

I F I NFE v i . " " THEN COTO 2 0 0RETURNprm h^ r,7 .

A TFOP N-1 T nFOR 1 . 2 TO Acnsup 90LET ASeN. A. BN-"6"GOSUP nnLET A s,H n

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300 NEXT i110 COSUP '30940 I F N-.1 THEN t E T AWN, q, E :

4PI 5350 I F 4 . 2 THEN LET A V N . A . E o,r 2

HP. 1 4/ 60 I E N- 5 THEN LET A l l e N . A,P. ,- C

HRO 11370 I F N. 6 THEN LET EPIPTN.P.E1).0

HRS 1 3380 I F N. 7 THEN LET A( N, A. 1 3 ) . 0

HRS 1 0390 I F N. 8 THEN LET 011(WA. EP. 0

HP, 9400 I F N. 9 THEN LET AWN, A. 13 ) . 0e410 I F 4 . 1 0 THEN LET A W N , A , P ) .

CHPS 7420 I F N. 11 THEN LET A W N , A . 8 ) .

CHRS 6430 I F N- 1 3 THEN LET P e ( NAA. e )-r i

-Ps 4

450 I F 14.15 THEN LET A W N . A . 8 ) .CHRS 3460 GOSUE 9 0470 I F N. 1 5 THEN LET AWN, A. 1 3 ) .

CHRIS 1 8480 COSUB 9 0490 LET AWN. A, E 0 . "S "500 FOP 1 . 1 TO 5510 COSUB 9 0520 LET Al l ( N, A, 8 - CHP 4 1 7550 GOSUB 9 0560 LET P 1 N, A. 8 ) . CHP 5 1 5570 NEXT I580 NEXT N” e LET 4 . 1600 LET L- 1610 Gosuo 90615 LET Y 1 . 8620 LET Y 2 - 8610 SLOw640 EDP I . 0 TO 5650 NEXT I660 PPI NT TAe 'fl op c : TAR u o s C T

qE1 IV r . vo H APE r114 T w r r p o w m nLOOP OF";TPP 1P-. P I .,T H r r .1 2 . T O

AEP"4r.5 PRI NT TAP i r . P Ci "YOU ENTEP

rHPOUGH AN OPEN O P ' TAP C,"THE DOOR SLAMS SHOT FEHTNn Yol l ".TAP USP C666 PEM i r P u t r o u t i r e670 I F OSP C-e T H E N C O TO 4 90 0

675 TE E t I N,7 2 0 0 T H E N P R IN T " YO U

APE FEELING T/ PED". TAE USP Oft680 PPI NT "NEXT " .690 I NPUT E t700 PP TNT RV TE8 1.1c-P705 I F 811-"" THEN rOTO 6 3 0710 I F Pe<1). "14" THEM COTO 9 1 5720 I F 811V1). "N" THEN COTO 1 9 4 0725 I F 1311C1)."U" THEN GOTO 1 2 2 0730 I F 130 (1 ) . "9" THEN COTO 1 4 9 0734 LET 811.430.8..735 I F 8 W TO 2 ) . "DO " THEN GOTO1270740 I F 8 9 ( 1 ) . " T " THEN COTO 1 6 6 0750 I F 8 0 ( TO 2 ) . "DR" THEN COTO2805755 I F 9 - ' S A V E " THEN GOTO 4 4 5

0760 I F 1311(1). "/ " THEN COTO 2 1 0 0770 I F 131V T O 23 . "SN" THEN COTO880780 FOP I . I TO 1 4790 I F STRO leCHRO e-e l l T H E N C O

TO 830800 NEYT I810 COSUP 1 9 0820 COTO 6 7 0830 I F E<VAL P e r . 0 THEN GOTO VA

L 0 0 * 1 0 0 . 3 0 0 0840 PRI NT " S O P P Y,C A N N O T D O T H A T

GOTO 8 7 0880 I F 7 ) 0 THEN COTO 1 1 5 5885 PRI NT "YOU HAVE JUST SNEEZE.

D" 890 LET E / 1 - P 1 N - 1

900 I F PNDN. 6 THEN COTO "'Y20910 GOTO 6 7 0911 PEM . 0 v . s915 I F T,. 0 T H EN C OT O 1153

820 PRI NT "WHI CH WAY"? e.N.E.W.SN

930 I NPUT 8 1915 PPI NT940 I F Fi l l -"" THEN COTO 4G00950 LET R . A - N T E I V I - • pse.1)=

960 FOP 1 . 9 TO 1 4970 LET E ( 1 ) . . E < I % - Fe flSOO NEXT 7990 LET Ar94-(04VIN."F"-e:Eilt<1).;

"1.1"‘,felon T r r e i v 1 TNEN r r i r n 1 4 4 n1006 I F Fur . o r N I O P rr-r . OP E ' lTHEN COTO 1 1 1 0

100A LE T N I P . A * ( L . A,A )1010 I F r c - " o " THFN r;OTO t l i n1020 I F Y l - A PND Y2. . 9 THEN cinTrlI 2001090 LET Y l - A1040 LET Y . F?1e5e I F rot-CHP$ T9 THEN GOTo 181

1060 I F DI . CHPS 1 5 THEN r.r1Tp 1 1 2

1065 I F DS.CHRS 1 7 THEN COTO 1 7 601070 GOSUET 3 2 2 01090 I F DO.CHRO 3 OP 011.CHPS 1 5THEN LET T . 11100 COTO 6 7 01118 I F USP C. USR 16593<)USP C THEN PRI NT "DONIK.YOU HAVE HI T A WALL")TA8 USP C.1111 LE T A. Y11112 LET 13.'1'21120 COTO 9 1 51125 REM monster s1130 LET ' - T N T e P 1,4 4 7 ) 0 34. 1

1140 PRI NT TAP LISP C)"HEPE I S A"WOLF N EAGLE TP I CO P D MUSHM

AN TPOG N U M P I P GROG " ( ? , TOX+7>TTP8 USP c ;

1150 COTO 10901155 PRI NT "WHAT ABOUT TNE MONSTER""1190 COTO 6 7 01200 PRI NT TAP USP C;"PAPDONTt"ITAP UsR r;1210 COTo q t 11215 PFM1220 I F 1-4 1 T H EN C OT O 1 15 5

1225 I F R o e L,A . 8 v " S " T H E N C O TO

13301 '510 IF FelT.T1 THEN COTO 1•0

1295 I F L - 1 7 THEN GoTn 4 4 1 0i:)40 LFT 1 - 1 +11250 PRI NT "YOH 4-4 0 V r 1 7 o N F I r p T k i

1;61.17i1TO 6 6 51270 I F TT43 THEN COTO 1 1 -.. - ;

•• •••. ?. . . Y•

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SINCLAIR USER Annual I1.M44 103

1275 I F SOWL.A.r. " S " THEN COTO1130

1280 I F F ( 5 ) ( 1 T H E N.C O T O 1 1 5 01290 LET Ls L- 11300 PRI NT "YON HAVE GONE DOWN THE STEPS"1310 I F Ls 0 THEN GOTO 1 1 7 01320 COTO 6 6 51110 PRI NT "NO STAI RS HERE"1140 GOTO 6 7 01350 PRI NT "YOU NEED A KEY"i sse COTO 6 7 01365 REM escsPed1370 PRI NT TAB USR CJTAB LISP C ; "WELDONE"ITA8 LISP C; ( "YOU GOT THE

JEWEL AND " AND E(3 ) )13 ) ;TA8 USRC; "E "1 E ( 2 ) ; " WORTH OF TREASURE

AND YOU";TAB LISP CI "COT AWAY WI TH " ; E ( 1 ) ; " SRO"1380 PRI NT TAB LISP C,T A 8 U S R C ; "

WOULD YOU LI VE ANOTHER CAME? " ;1190 I NPUT BO1400 PRI NT 80 ;TAB USR C;1410 I F BOs"" THEN COTO 1 3 8 01420 I F 841(1)s"Y" THEN RUN/ 425 CLS1430 RAND OSP. 166011431 REM d i e d1440 PRTNT TAB U P C "wHAT A PTT'Y O U HAVE D I E D " 1-0 8 U S P C J ( " B UT

YOU S TI LL COT THE JEWEL AND "ND E ( 3 ) ) 0 ) , TA8 LISP C;"YOU GOT f "E t 2 )," WORTH OF TREASURE'

145e FOR I s 0 TO 91460 I F U P 16563 THEN NEXT I1485 COTO 1 3 8 01486 REM r i O ht1490 I F 1<1 THEN COTO 47001495 LET 1 8 s I NT ( RND* 2 0 0 0 )1500 LET M I N T (RND* MS)1505 I F E ( I 3 ) > 0 THEN LET MsPI -INT(RNDO100)

1510 LET Ys I NT ( RNDI E ( 1 ) )1515 I F E c 9 » 0 THEN LET YsYeI NT( RND* E ( 1 ) )1520 LET X s I NT (RND* 6)* 64. 1153e PRI NT TAB USR C;"OUCH K I C K

KNOCK EIFITTERBRSH P UNCH " ( X TOX . 5 )

1540 LET E ( 1 ) s E ( I ) - M1550 I F E ( 1 ) <1 THEN COTO 1 4 4 01560 LET P1SsMS-Y1570 I F MS<1 THEN COTO 15901580 COTO 1 5 0 01590 PRI NT TAB LISP C;"YOU KNOCKFD THAT MONSTER A MI LE"1600 LET T+01605 I F AO ( L, A, 8 ) CHRO 1 5 THEN LET AO<L41, 0)=CHRI 01610 COTO 6 7 01620 PRI NT TAB USR CJ " AND DPAwNATTENTION TO YOURSELF"

1625 LET T s t1630 COTO 1 1 3 01640 REM t a k e1660 I F T>0 THEN COTO 11551670 LET DOsAI I KL, R, 0)1675 I F DO+CHR0 1 5 OP 0111••"0" ORDO+CHR0 0 OR Dias"S" OR DOsCHRO 17 OR DIP.CHP0 1 8 THEN COTO 1 7 4 01676 PRI NT "OK"1680 I F DOw"G" THEN COTO 1 7 2 01690 LET E(CODE DO).+E(CODE D0 ) +11700 LET A E L , A , B ) C H R O 01710 GOTO 6 7 01720 LET U 2 ) + U 2 ) + I N T <RND* 1000

1730 COTO 1 7 0 01740 PRI NT "NOTHING HERE TO TAKE

1750 COTO 6 7 01760 PRI NT TAB LISP C;"YOU HAVE FALLEN I NTO MUSH" -1770 LET E ( 1 ) s E ( 1 ) - I NT (RND*1001)1780 I F E ( 1 ) <1 THEN GOTO 1 4 4 01790 PRI NT TAB LISP C;"BUT YOU ARE ALL RI GHT"l eee COTO 6 7 01810 PRI NT "HERE I S A WT7APO ANDHE CI VES";TR8 USR C;"YOU AN 0 8 J

FT AND HE SRYS. "

1820 LET AO(L, A;8) . -CHR5 ( I N TDal l )-0. 4)1825 LET D l i c l O ( L,A,B N

1830 I F D0-C4R0 1 2 THEN COTO 1 8 201835 COTO 1 0 7 01836 REM he l p1840 I F R11D. 7 THEN COTO I 1 o01950 PRI NT "SORRY;NO HELP HF.PE"1960 LET E ( 1 ) s E ( 1 ) - 1 01970 I F E ( 1 ) 1 1 THEN COTO 1 4 4 01980 COTO 6 7 01990 COTO 1 8 2 02000 COSUB 1 9 52004 REM dr oP2005 I F 1 >0 THEN GOTO 1 4 4 02010 PRI NT "WHI CH NUMBER WI LL YOU DROP? "J2020 I NPUT 81112025 PRI NT 8 0 ; TA8 USR CJ2030 FOR I s 3 TO 1 42040 I F S I PS I . E . THEN COTO 2 0 8 02050 NEXT I2060 COSUB 1 9 52070 COTO 2 0 1 02080 I F E(VAL 8111)<1 THEN COTO 4 5002085 LE T E(VAL 130).E0IFIL 8 1 ) - 12090 COTO 6 7 02095 REM i f2100 PPI NT TAB LISP C;"YOU HAVE

" ; E ( 2 ) ; " OF TREASURE";TAB LISP C;" AND " I E ( 1 ) ; " S P * AND YOU ARE 0N")TAB LISP C)"LEVEL " i L2110 GOTO 8 1 02120 SAVE "PHOENI x"2130 RUN3100 PRI NT "YOU HAVE " 1 E < I ) ; " S P

3110 GOTO 6 7 03200 PRI NT "YOU HAVE k " ; E ( 2 ) ; " 0F COLD"3210 COTO 6 7 03215 REM obJ e c t s3220 PRI NT TAB USK. r :"HERE I S A";TAB USP C ; ( " P I T OF MUSH" AND DIPsCHRO 1 7 ) " W I S E WIZARD" AND Dais3220 PRI NT TAB LISP C:"HFRE TS A";TAB LISP C ; ( " P / T OF MUSH" AND DOsCHR$ 1 7 ) ; ( "WI S E WIZARD" AND DOsCHRO 1 8 ) J " S O L I 0 WALL" AND D5 - 1 0") ; ‹ "S I LV E R SWORD" AND De•CHR0 6))‹"GOLD RI NG" AND D5=CHP0 7 ) ; ( "TORCR" AND DOsCHRO 8)1("POSH SHTELD" RND DOsCHRO P); / " B U C K E T O F

WATER" AND DOsCHRO 1 0); ( " S I L V E RWAND" AND DOsCHRO 1 1 ) ; ( " S UI T OFHEAVY ARMOUR" AND DIP-CHIP. 1 3 ) 1 ( "WOODEN CLUB" AND DO-CHR* 1 4 ) ;,f " STRIP CASE" AND D5 -" S "):1" C P R O D r

HOENIY CORPDTOr n JEWEL" AND DS, ,

ippki

CHF17 ' Po l? .TY fltW riOWTFP

ANC. (4-CHPO 1 5). ' " H O A R C . O F T R FA

SURE" AND DOs"C") ( "8 0 0 Y OF SPEtLS" AND ("OsCHRO . 4 " LOAD OF NOTHING" AND DOsCHRO 0 ) 1(" C O L D E N vEY" AND DesCHP4 5 ) . TAR US$:. C,3230 RETURN1240 REM 1 1 1 ht3300 PRI NT TOP OSP C "THE An4ErL/CHTS OP";TAA LISP r1105 PRI NT TAP l i 5 r "NoRTH" TArOSP r

1310 I E T N e - n s,1 . n-e n

r n G nS UP 3 2 2 07j1741 PRI NT TAP oSROSP r

p r i1 1 l n r x f - u p-41rm r P i t n- T M 1 1-p r," F A ST " ; Th r

uSR C•1140 LET DO-Atel . 1 1 . 8 4 .,0 e 6 ) )3 1 4 5 GOSUe 1 2 7 01150 PRI NT TAP NSP D,' W E S T ",T A r

C3355 LET D 0 +,1 0 ( 1 „ A ,8 - 0 > 1 ) )

3360 GOSUB 3 2 2 09363 cosua 1 9 63370 COTO 6 7 03400 I F TM3 THEN COTO 11553405 PRI NT TAB USR C;"THE SPELLBOOK MAKES SOMETHING";TA8 USR C," FOR YOU"3410 LET E ( 1 ) s E ( 1 ) - I NT (RND* E(1: .

3420 GOTO 1 8 2 03500 COTO 5 1 0 03600 I F T( 1 THEN COTO 4 7 0 03610 PRI NT TAB USP C;"YOUR 5W0A7, KILLED THE MONSTER"3620 COTO 1 6 0 03700 PRI NT TAB LISP Cr "TO CET OUT

OF THE TOWER;YOU MUST";TRE1 USPC;"CO DOWN THE STEPS ON THE P O T-OM";TR8 USP C;"FLOOR"3710 COTO 6 7 03800 PRI NT TAB USR C;"YOU SWITCH

ON THE LI GHT AND SEE. "3810 COTO 3 3 0 53900 COTO 5 1 0 04000 I F ALL, A, E1). . CHRO 3 AND 1 ) 0

THEN COTO 4 0 2 04010 COTO 5 1 0 04020 PRI NT TAB USR Ci"WATER HASPUT OUT THE PHOENIX"4e30 COTO 1 6 0 04100 PRI NT TAB LISP C; "WI TH A WAvE OF YOUR WAND;YOU RRE";TA8 LISPC;"ON THE NEXT LEVEL"4110 I F L<1 5 THEN LET Ls1_4.14120 COTO 16004300 COTO 5 1 0 04400 I F 1<1 THEN COTO 4 7 0 04405 PRI NT TAB USR C;"YOU SURE 9RSHED THAT MONSTER"4410 COTO 1 6 0 04430 PRI NT "THESE STEPS DO NOT C0 UP"4440 COTO 6 7 04445 REM P i e c e s i v e4450 I F USR 16583<)USR C THEN PRINT "START TAPE RECORDER AND PRESS";TRO LISP C;"NEWLI NE WHEN READY. ";TAB USR CI TR8 USR C;"r em l o sd l x k l " ; TAB USR C;4460 I NPUT BO4470 SAVE "X x "4488 COTO 6 7 04500 PRI NT "NOTH/ NC TO DROP"4510 COTO 6 7 04600 PRI NT TAB LISP CJ4610 COTO 9 2 04700 PRI NT "NOTHING HERE TO BASH

i

r,".".0OTH";TA17'

n+e nt g

4710 COTO 6 7 04800 REM s c r o l l o f f l a s t wor ds4900 PRI NT TAB LISP C;5000 I F PEEK (PEEK 16396ePEEK 1 6397* 2564. 1)(>128 THEN COTO 4 9 0 05010 COTO 6 7 55100 PRI NT "YES.YOU HAVE I TN5110 COTO 6 7 0


SINCLAIR USER Anrtual 1984

HelplineM I N 1 1 1 11 1 11 1 1 11 . . 1 1 11 E N V

IM 1 0 1 EE• M N IME,11I I I 1 I I • --- al 110 ell'A I I IIII I I I EIP El I I I IES V I E SI A k I I M I M II I I I I I gib ow i 6 111, '1" 1 1 1 1 1 I " I F IE N I

M I I n OMNI 1 1 0 1 1 . 1 1 W = 1 :O M EOM 101"1"---

111 N M dal= 1 1 1 1 1 . 1 1 . 1 1 1 E in 1.1O M M E M E M I E OM illin• ElEli N M Ellill IIU m M E M

M I DM I N 111111111 •• 1•111 We l ,

I.

IMOD NEVUS

I .'

Our resident expert, Andrew Hewson, hasagain been busy answering queries. In thissection he has collected all his advice on

particular subjects to give you the best helpin making the ownership of a Sinclair

machine more fulfi lling.

105

I 06

PEEK, POKEare explainedEVERY MONTH a selection of

queries from readers on thedifficulties they experience are

answered in Sinclair User. Here is aselection o f those which offer advicewhich will be of universal interest.

David Anthes o f Bridgport writes:My ZX-81 has a bug. When I POKE57 into various addresses as p e rpage 163 of the manual, I get weirdeffects. Somet imes t h e mach inecrashes but Sinclair claims there isnothing wrong with it .

When you enter PRINT PEEK ad-dress, your computer PRINTs a posi-tive i n te r number between 0 and 255inclusive. That is the number whichyour machine holds in the byte at loca-tion "address". The value of "address"must be a positive integer between 0and 32767 on the 16K ZX-81 or Spec-t rum.

POKE is the complementary com-mand to PEEK. It puts a number into alocation. The form of the command is:

POKE address, numberVrhere address is a positive integer in

the range 0 to 32767 — I6K machines— and number is a positive integer in

• Please address probltms and quertes to AndrewHermon, Helpline, Graham Close, Riewbu ry,Oxfordshire_

the range 0 to 255 i t is a dangerouscommand because POKEing the wronglocation can cause the machine to crashfor any one o f a hundred reasons.PEEKing is a means of looking at whatyour computer is doing, whereas PO-KEing is a way of putting a spanner inthe works; i f you put the spanner in thewrong place or the wrong spanner in

the right place you can cause havoc.John Hawes of Glamorgan wants to

PEEK the ZX-8I display tile. He asks:Is it possible to discover whether agiven character is at a given posi-tion in the display o f the I 6K ZX-81?

There are two golden rules to remem-ber when manipulating the ZX-8 I dis-play. They are:

The ZX-8I display file must alwayscontain at least 25 bytes filled with theNEWLINE character, decimal 118.

The I K ZX-81 display file containsonly the characters which have beenPRINTed or PLOTted, plus sufficientspaces to fi ll any gap between the left-hand side of the screen and the charac-ter in question. The I6K ZX-8 I displaytile contains 25 lines o f 32 charactersunless SCROLL has been used sincethe last CLS. The following routinePRINTs the character at row R, col-umn C of the 16K ZX-8I display file:10 FOR I=0 to 520 PRINT "ABCDEFGH1JKLM

NOPQRSTUVWXYZ";30 NEXT I100 LET D =PEEK 16396+256*

PEEK 16397110 INPUT R120 INPUT C130 PRINT AT 21,0; CHRS PEEK

(11) + 33*R + C)Peter Bankes of Debenham asks: Is i t

possible to poke the Spectrum toget caps lock?

The caps lock condition is stored inbit 4 o f FLAGS2 at address 23658 inthe system variables area. When bit 4 isset, all entries will appear in capitals.Hence a program c a n determinewhether caps lock is set by checking thestatus o f that b i t and altering i t i frequired.

The condition o f b i t 4 may bechecked from Basic in a somewhat cum-bersome fashion as illustrated by:10 IF INT(PEEK 23658/8)=2*INT

(INT(PEEK 23658/8)/2) T H E NPRINT "CAPS LOCK NOT SET":GOTO 30

20 PR IN T "CAPS LOCK SET"30 STOP

To set bi t 4 from Basic and henceturn on the caps lock enter

POKE 23658, PEEK 23658+8To turn i f off again, enter

POKE 23658, PEEK 23658-8Alternatively you may wish to use the

ROM routine which "toggles" the capslock. The routine is located at address4317 (10DD hexadecimal) and succes-sive calls of the form

RAND USR 4317turn the caps lock on and off.


Machinespeak

Switchsetting

Off Off Off Off On On On On

State Re-set Re-set Re-set Re-set Set Set Set SetBinarypattern

0 0 0 0 1

Bitnumber

7 5 4 3 2 1 0

ANY PEOPL E have h a dproblems with machine code.John Stevens o f Hammer-

smith, London writes: I am trying tolearn how to write machine codeprograms but I am finding it diffi-cult to understand the meaning ofsome of the words which are used.Can you explain as fully as possiblewhat is the difference between a bitand a byte, and between a registerand a variable?

A b i t i s the fundamental buildingblock o f computer memory and canexist in only one of two states. The twostates can be thought of as representingON or OFF; TRUE or FALSE; YES orNO; UP or DOWN; MAL E or FE-MALE or any other pair o f logicallyopposite conditions. The mechanism bywhich a computer memory works is notreally important to us but in the Sinclaircomputers the state o f a bit is memor-ised by setting a microscopic solid stateswitch either ON or OFF as appropri-ate.

The usual notation is to think of onestate as the ZERO state and the other asthe ONE state. A bit is considered to beset when it is in the state representingONE and to be re-set otherwise. Thatnotation allows us to speak o f a givenpattern o f bits in terms o f its binaryequivalent and by converting the binarynumber to a decimal each bit patterncan be given an exceptional positiveinteger number.

For example, consider eight bits o fwhich the right-most four are set andthe left-most four are re-set as illustrat-ed in table one. The binary pattern o fthe eight bits can be converted to adecimal i f it is remembered that, in abinary number, the right-most columnis the units column; the next column tothe left again is the fours column and soon, doubling at each move to the left.The decimal equivalent of 00001111 istherefore:

0*128-1-0*64+0*32+0*16-1-113 +1M+ I*2-1- 1 '1' 1 = 1 5

Obviously it is inconvenient to refer tobits as the right-most or the third fromthe right and so the convention is adopt-ed of numbering the bits from the right,starting at zero as shown in table one.

1984 1 S I N C L A I R US E R A n n u a l 1984

When that convention is used the num-ber o f each bi t is also the power towhich 2 must be raised to give the valueof the column. That is:

2 bit number --- column valueBit 3, for example, is in the eights

column because 2'I chose to consider a group o f eight

bits together because of the Z-80A mi-croprocessor at the heart o f the Sinclaircomputers is designed to operate oneights bits at a time. The term 'operate'covers all the types of task which the Z-80A can perform directly, such as addi-tion, subtraction, rotation, logical

AND, and the like. Thus although a bitis the fundamental unit o f computermemory, bits are usually manipulatedtogether in groups of eight, so a groupof eight bits is called a byte — pro-nounced bite.

There are 256 ways of arranging thecontents o f a group of eight bits. Thefirst i s 00000000, t h e second i s00000001, the third is 00000010. Thuseach of the bytes in RAM can be used tohold a single positive whole numberlying between 0 and 255 inclusive bysetting or re-setting the eight bits in thebyte according to the binary equivalentof the number.

The Z-80A does not alter the con-tents o f memory directly when i t i s

executing a program; rather i t copiesthe contents o f a location in memoryinto one o f several special locations inthe microprocessor called a register andthen operates on the contents o f theregister. The Z-80A is a powerful mi-croprocessor because it has many regis-ters and so it can hold several numbersat once, thereby reducing the need tomake time-consuming transfers betweenthe processor and memory.

Most o f the registers have one ormore special features. The most import-ant one is the 'a' register or accumula-tor, so-called because the results of mostarithmetic o r logical instructions areaccumulated in the 'a ' register. Someinstructions use a second register as asecond source of data together with the'a' register.

For example the instruction:add a,b

means add the contents of the 'a' regis-ter to the contents of the 'b' register andleave the result in 'a'.

Thus a register is a dedicated locationin t h e microprocessor wh ich h a sspecific attributes and functions. A vari-able is a location or group of locations inRAM which are used by a particularprogram. I f the program is written inBasic or another high-level language,the variable is given a name and allreferences to the variable are madeusing the name.

The next question, from Alan Ber-mingham of London, follows from theprevious one. He asks:

What do the following programsdo — a n assembler, a d isas-sembler, an interpreter, a compil-er?

A machine code routine consists of asequence o f instructions which the 7,80A understands directly with no needfor prior interpretation. The simpler

Table 1. Three ways of representing a group of eight bits of which the four left-most arc re-setand the four right-most are set. The bit number is shown on the bottom line.

10 F O R 1..23296 TO 2332520 I N P U T Z$30 I F Z$="S" THE N STOP40 P R I N T Z.$;" ";50 L E T Z5(1)=CHRS(CODE ZS(1)-7*(CODE Z$(1) 57))60 L E T Z$(2)=CHRUCODE Z.S(2)--7*(CODE Z$(2) 57))70 P O K E 1,16*CODE Z$(1)+ CODE Z$(2)---81680 N E X T I

Table 3. A Spectrum program to load 30 two-character hexadecimal codes into the printerbuffer .

107

108

instructions are held i n one by te o fmemory b u t t h e mor e complicatedinstructions can occupy as many as fourbytes.

Generally, the instructions are ex-ecuted in the order in which they areencountered, although there are excep-tions. The Z-80A keeps a note of fromwhere the next instruction is to come bymeans o f a special register pair calledthe program counter. Thus i f the loca-tion pointed to by the program countercontains the number 128 in decimal —80 in hexadecimal — the Z-80A will addthe contents o f the 'a' register to thecontents of the 'b' register and leave theresult in the accumulator, because 128is the decimal machine code instructionfor

add a,bThe decimal o r hexadecimal codes

'A disassembler is ofuse when analysing

code written bysomebody else'

for all the 600 or so instructions in theZ-80A instruction set are diffi cult t oremember and so for that and otherreasons machine code programs arealmost always written using an assem-bler program. A n assembler convertsinstructions like add a,b to the correctcode. I t also allows the programmer toname variables, add comments and givelabels to various points in the programand to call subroutines using the labels.A good assembler will have other facili-ties as well, a ll aimed at making the

Hex code2A 65 5C4441)3E 0 0777EFE 0 0Co3E FF777EFE FFCoA723ED 72C8AlED 7A03IS E7

Assembler codeLD HL,(23653)LD B,HLD C,LI.D A, 0LD (HL),ALD A,(HL)Cl ' 0RET NZLD A,255LD (111),ALD A, (HL)CP 255RET NZAND AINC HLSBC HL,SPRET ZAND AADC IlL,SPINC BCJR — 25

programmer's job as straightforward aspossible.

A disassembler performs the oppositefunction to an assembler; it converts asequence of numbers into a sequence ofmnemonics which are easier to under-stand than the original code. A lis t o fthe more important mnemonics is givenin the Sinclair manuals in Appendix A.A disassembler is of use when analysingcode written by somebody else to dis-cover how it works.

The output from an assembler is aprogram which the microprocessor canunderstand directly because it consistsof machine code instructions. I n con-trast, a program written using an inter-preter, such as Sinclair Basic, is held inRAM in more or less the form in whichit was entered by the programmer.

Interpreters are high-level languageswhich bear lit t le or no relationship tothe instruction set o f the processor onwhich they are run. Every t ime theprogram is executed, however, each linemust be analysed by the processor be-fore the required action can be taken.The princ ipal disadvantage o f the sys-tem is that the programs can be slow toexecute, because the processor spendsmost of its time determining what eachprogram line means.

A compiler circumvents the problemby analysing each program line onceonly and then storing a sequence o fmachine code instructions whic h areequivalent t o t h e or iginal program.Thus t he speed o f a machine codeprogram is obtained without losing theconvenience o f a high-level language.The machine code produced by a com-piler can be somewhat tortuous andinflexible and s o when effi ciency isessential an assembler is used instead.

CommentSet HI - to address of spare spaceCopy HLto BCSet A to 0Copy A to memoryCopy memory back to ACompare resultReturn i f errorSet A to 255Copy A to memoryCopy memory back to ACompare resultReturn i f errorClear carry flagIncrement HLSubtract stack pointer from HLReturn i f finishedClear carry flagAdd stack pointer to HLIncrement BCRepeat for next memory location

Table 2. A Spectrum machine code program to test each memory location between thebeginning of the spare space—marked by the STKEND system variable—and the bottom ofthe stack.

MemorygrowthNICHOLAS KENNEDY of Bel-

fast, Geoffrey Hulme of Stoke,and Gareth Ricky of Notting-

ham, are interested in adding RAM totheir ZX-8Is or Spectrums. They askquestions like: What are the advan-tages and problems of using a 64KRAM on the ZX-81? Can 16K Spec-trum programs be loaded into the48K machine? C a n I 6 K Z X - 8 IRAMs be used on the Spectrum?Why is there a difference in pricebetween add-on RAMs for the Mod-el One and Model Two Spectrums?

In the face o f such a barrage I con-tacted Stephen Adams, who specialisesin dismantling Sinclair computers for .fun, for the latest information. Mos tpeople know that 64K of total memory— i.e., RO M and RAM — is the mostwhich can be used with the Z-80 micro-processor without special paging facili-ties. I n the ZX-8 I the bottom 8 K o fmemory is reserved for the ROM — theset of machine code instructions whichgive the machine its character. I n theunexpanded machine the next 8 K isabsent and then there is I K of RAM ataddresses 16K to I7K.

When a I 6 K R AM pack is added itdisplaces the I K o f RAM t o occupyaddresses 16K to 32K. The implicationof that design is that Sinclair intendedoriginally to release a new RO M withenhanced facilities to occupy addresses0 to 16K.

In fact, it has never done so but othermanufacturers have stepped in to fi l lthe gap with graphics units and assem-blers; 16K and 32K memories are alsoavailable which occupy addresses 16Kto 32K and I 6K to 48K respectively.

In either case, all the extra memory isavailable directly to the Basic system;64K RAMs are available of which 48Klies between addresses 16K and M Kand is available for normal use. Another8K replaces the "missing" 8K of ROMbut t ha t p a r t o f memory c an b ePEEKed and POKEd only from Basic.The fi nal 8 K is present but unused,which means presumably that the man-ufacturer also has some future appli-cation in mind.

The memory situation for the Spec-trum is equally complicated bu t f o rrather different reasons. In this machinethe RO M occupies 0 to I 6 K and the

Coortruaed am page 110

SINCLAIR USER Annual i 964

BOOK A TEST FIGHT TODAY!

• • •• 000

They're all-action games designed to push yoursenses t o ne w kni ts. Take "Brain Damage";trapped in your computer's micro-circuits you'llneed all your filYSOUF005 to defeat the CPU's electronpanzers a n d if they don't get you, the RoguePrograms will

When you get your breath beck you'll be runningfor your life again in "Exterminator". Transportedimo the future you'll fi nd that earth is a veryrkfferent place. Robots rule the world and thehuman race is almost extinct, there's only onefamity left You have to save them b u t hurry youdon't have much time.

You'll love a REAL fight on your hands when you tackle our new games.

Sitting in defense command, your hands poised arthe controls, you scan the !sky for activity knowingthat it will shortly erupt. "Armageddon" is about tobegin • o n l y YOU can save the last sox cities.

If you're still in control of your senses you can tryyour hand at rescuing the 1114ner5 trapped on Than

easy you think! Ride your ship through the mini-meteor storm and pick up the men. But you didn'treckon on the corporation spaceships making this"Mission Impossible",

Book your test fl ight today- B uy a ny o fStiversoffs new games and find out if you're realtyin control

All games run on any EX-SPECTRUM and cost £595. write today for full details of our complete range of software

Selected titles are available at W.H. SMITHS. BOOTS, JOHN MENZIES, and at all good computer stores.

To- Savenpoit Lid. London House. 271 /273 King Si,

London Wti

Meese send me

I enclose a ollsoustpostel or f o r

!Nom debit nly ACCESS NoName

Address•

110

6,71f, !WM putge I tPt

standard I 6 K R A M occupies the re-maining area up to 32K. T he easiestway to add more memory is to returnthe machine to Sinclair with a suitablecheque and it w ill do the job, but thatmeans doing without your machine fora time.

Add-on memory is available f r omother manufacturers but Sinclair has re-designed the c ircuit board completelysince its or iginal launch and so i t isnecessary to determine whether yourmachine is an early version — modelone — or a re-designed version — modeltwo,

Most model one machines have greykeys, whereas model two has light bluekeys. T o be certain which model youhave you should look into the machinethrough the slot in the rear where theedge connector is situated.

I f you have a I6K model one you willsee a vacant I6-pin socket on the printedcircuit board ly ing to the left of the slotand about two centimetres from the rearof the machine.

I f your machine is a 48K model onethe I6-pin socket will not be vacant butwill act as the connector between themain printed circuit board and a subsid-iary board on which the extra memoryand decoding chips are mounted.

In that case you w il l also see sevencircular capacitors, each rather smallerthan a halfpenny piece, mounted on thesubsidiary board in a line facing the rearof the machine.

The I6-pin socket is not present onthe model two because there is spaceavailable on the re-designed main print-ed circuit board for the extra memoryand decoding chips. Instead, the verylarge Z - 8 0 microprocessor c h i p i sclearly vis ible through the s lot, ly ingapproximately below the 9 key on thekeyboard.

The reason for the price difference

for add-on memory between model oneand model two machines is apparent.To extend a model one the necessarychips must be mounted on a suitableboard t o be located above the mainboard. T o extend a model t w o thenecessary chips need only to be insertedin the sockets already provided on themain board.

It is not possible to plug a ZX- 8IRAM pack directly into a Spectrum,although a t least one company nowmarkets a small adaptor to allow you todo so, thus giv ing 32K of RAM with aI6K ZX-8I RAM pack or 48K of RAMwith a 64K ZX-8I R AM pack.

Programs written for a 16K or 32KSpectrum should work without modifi -cation on the 48K machine and it is safeto assume that all 16K programs avail-able commercially will run on the largermachines. O f course, the converse is nottrue; it is most unlikely that a programwritten for 48K would function on asmaller machine.

Henry Evanson o f Bromboroughwrites: I wish to use the 48K soft-ware packs but the first 1 purchasedwill not load. How can 1 check that 1have received a 48K Spectrum andnot a 16K machine by mistake?

The answer is to check the high byteof the P- R AMT pointer a t address23733 by entering:PRINT INT (PEEK 2373314)-15; " K "

The machine sets the contents o f23733 to 255 — or 127 on the 16KSpectrum — when it is plugged-in andthe line above performs a simple calcu-lation and PRINT s 1 6 K o r 4 8 K asappropriate.

At any particular time a user may runout o f memory. Michael Fawcett has aproblem with his ZX-8I in that regard.He writes: When 1 get near to theend o f entering a part icular pro-gram t h e cursor disappears an dwhenever a k e y i s pressed sub-

sequently, a l e t t e r d isappears.What is wrong?

Many ZX-81 users w il l recognise inFawcett's remarks that he is runningOut o f memory. T he only guaranteedsolution is to buy an add-on RAM pack,although a certain amount of space canbe saved by deleting R EM statementsand shortening P R I N T statements,The Spectrum, inc identally , emits alow-pitched buz z w hen memory i sshort.

A check on the amount o f memoryleft can be made at any time by enteringthe following REM at line 1: •

I R EM RESERVE SOME SPACEand POKEing the following numbers:

33, 0, 0, 57, 237, 91, 28, 64,167, 237, 82, 68, 77, 201

into locations 16514, 16515 1 6 5 2 7(on the ZX-8 I).

The equivalent locations on the Spec-trum are 23760, 23761 2 3 7 7 3 andthe numbers to be POKEd are the sameexcept that 101, 92, should be sub-stituted for 28, 64.

In each case a short machine coderoutine is loaded into the space reservedin the R E M statement and then theamount of memory left can be PRINTedby entering:PRINT USR 16514 — 24; "BYTES"or in the case of the Spectrum:PRINT LISR 23760 — 24: "BYT ES"

Robert King of London asks: I havea program which works well on myfriend's Sp e c t ru m b u t a l w a y scrashes on mine. I suspect a fault inthe R A M . H a v e yo u a programwhich checks each RAM location inturn?

Checking RAM involves setting ev-ery bit o f every byte, checking that i tremains set, and then re-setting everybit and checking that it then remains re-set. Setting every bit in a byte is equiv-alent to POKEing 255 into that byte.Similarly, re-setting every bit is equiv-alent to POKEing in O.

Obviously it is not possible to POKE.numbers in to every memory locationwhile the machine is running, becausethe computer w i l l crash, but a partialcheck can be made b y testing everylocation in the spare area of memory.

The program in table two runs such acheck. It can be loaded using an assem-bler o r us ing the s imple hexadecimalloader listed in table three.

The program checks every locationup t o the bottom o f the stack andreturns the address at which it stops—about 32575 in the I 6 K machines and65343 in the 48K machine when theyare working correctly.

SINCLAIR USER Anniddi 1984

Storing data instring arraysUNDERSTANDING data stor-

age and arrays is somethingwhich puzzles many readers.

Norman Dis ley o f Cheshire has acollection o f about 50 music cassetteswhich he wishes to catalogue on a Spec-trum. H e writes: Eac h t une w ou ldrequire six or more entries — titlename, soloist, and as each cassettecontains about 30 titles the collec-tion would use almost a ll o f the9999 lines of the Spectrum, leavinglittle r oom f or la ter insertions.What can I do?

Several people have written outliningthe same idea o f using the 9999 pro-gram lines available to store up to 9999items o f information. T h e techniquehas the merit o f simplicity in use butthere is no possibility of writing a pro-gram to search, sor t o r PR I N T theinformation.

The conventional technique is t ostore the information in a numeric orstring array. T he length o f a numericarray is 4+2* number o f dimensions+ 5* total number of elements.

Thus, for example, the two-dimen-sional array N(2, 5) which contains 10elements occupies 4 + 2*2 + 5*10 = 58bytes.

A string array occupies 4+2* num-ber o f dimensions + total number o felements a n d s o Z s ( 2 , 5 ) uses4+2*2+ 10= 18 bytes.

Disley wishes to store string data andso allowing 10 characters per entry, sixentries per tune, 30 tunes per cassetteand 50 cassettes, he would need t odeclare a string array:

ZS(50,30,6,10)This would occupy

4 + 2*4 + 50*30*6*10 = 90,012 bytesThere are about 10,000 bytes avail-

able to the user in the 16K Spectrumand about 42,000 bytes i n the 4 8 Kmachine. Clearly Disley will not be ableto hold all the data in the machine at thesame time in that manner. The problemwould s till arise even i f he were to useprogram lines, as each character in theline occupies one byte and there is anoverhead of six bytes per line.

Space could be saved by using fewerthan 10 characters per entry, perhaps byusing abbreviations. Alternatively, the

984 I S I NCLAI R USER AnPrual 1984

six entries per tune o f 10 characterseach — 60 characters in all — could becombined into a single entry of, say, 30characters so that less space was wastedon trailing blanks.

A more sophisticated solution wouldbe to hold all the information in onelong string array and to use a second,numeric, array to point to the locationin the string array at which each entrybegan. The slicing technique describedin Z X Spectrum Basic Programmingcould then be used to select a givenentry. The following program demon-strates the method:

10 D IM P(I01): REM DECLAREPOINTER ARRAY

20 LET PZ= 1

'I want to enlargethe array

in a program'30 D IM ZS (1000): REM DECLARE

STRING ARRAY40 INPUT "ENTER DATA"; AS50 IF P(PZ)+ LEN AS > 1000 GOTO

10060 LET P(PZ+1)=P(PZ + LEN AS)70 LET Z$ (TO P(PZ+ I))= ZS

(TO P(PZ))+ AS80 LET PZ=PZ + I90 IF PZ < 102 THEN GOTO 40

John Brookes o f Bromsgrove writes:The books are generally easy toread but none o f them explainsarrays sufficiently clearly for uswooden-headed types. C a n y ouhelp?

Most tasks performed by computerscomprise r eading infor mat ion i n t omemory, manipulating the informationaccording t o a program o f s toredinstructions, and w r i t ing t he infor -mation out of memory.

The information stored in memorymust be organised in some convenientfashion so that the person who writesthe program of instructions can do hissob. Mos t high-level languages allowthe programmer to declare variables ofvarious kinds so that different types ofinformation can be stored and treated inappropriate ways.

The ZX-8 I and the Spectrum eachallow six types of variables — numericwith a single character name; numericwith a multiple character name; controlfor a FOR-NEXT loop; string; stringarray; numeric array.

The fi rst two types are identical inuse, as they can each store only a singlepositive or negative number. Most pro-grammers try to give a name to a vari-able w h ic h reminds t h e m o f t h einformation i t holds. For example, abank account program might hold thecurrent balance i n a variable calledBALANCE.

In many programs s imilar in for -mation is to be stored concurrently andin that s ituation the program is alsolikely to become unnecessarily cumber-some because the same operation mustbe performed on many variables, eachwith a different name and thereforerequiring a separate piece of code.

The bank account program might berequired t o s tore the amount spentusing each o f 30 cheques in a chequebook. The amount spent using the firstcheque could be stored in a variablecalled CHEQ UE. T he same variablecould not be used to store the value ofthe second cheque because only onevalue can be stored in a numeric vari-able.

The act o f entering the second valueover-writes the first value, causing it tobe los t, hence the programmer mustthink o f a new name for the secondcheque. Most programmers would runout o f inspiration before they hadnamed all 30 cheques.

One way o f naming a l l 30 whichwould no t require t oo muc h effor twould be t o c all them CHEQ UE1,CHEQUE2, CHEQUE3. That is theidea o f an array. Sinc lair arrays arerestricted t o single-character names

10 PRI NT AT 0,11;"CHEQUEBOOK"20 PRI NT AT 2,0;"ENTER CURRENT

BALANCE"30 I NP UT BALANCE40 DI M C(30)50 PRI NT AT 2,0;"ENTER EACH

CHEQUE I N TURN"60 FOR I = I TO 1070 PRI NT AT 4,0;"CURRENT

BALANCE " ; BALANCESO I NP UT CO)90 LE T BALANCE-BALANCE-COI

100 NE X T I110 CLS120 PRI NT "CHEQUE NO. ", "VALUE"130 FOR I •1 TO 30140 PRI NT I,C(I)ISO I F PEEK 16442-3 THEN SCROLL160 NE X T 1Table 1. A simple cheque bookprogram.

i l l

only but that is a small price to pay forthe flexibility they provide.

Table one shows a simple chequebook program which uses an array, C,of length 30 to hold the value o f eachcheque as i t is entered. The programalso shows the use of another variable,1, to count through the array selectingeach element of the array in turn. Whenall the cheques have been entered theprogram prints the value o f each inturn.

Simon Smith o f Battersea, Londonhas a more complex question concern-ing arrays. He writes: I have a ZX-81and recently bought a 64K memoryto replace the 16K RAM pack I hadpreviously. I now want to enlargethe array in a program which in-dexes my record collection to makeuse of the extra memory space. Isthere any way o f doing so, short o fcopying the data to another array?

Defining a new array and copying thedata across using a FOR-NEXT loopwould certainly be the easiest way o fdealing with the problem. The disad-vantage is that the new array can occupyonly the space which is not used by theold array; hence when the old array isdeleted — by DIMensioning i t to zero— the memory space i t occupies re-mains unused. I f the old array was 12Kbytes long and a further 32K bytes o fmemory was added, the new array couldoccupy only 32K o f the total o f 44Kbytes available.

Hex code Assembler code Comment Hex code Assembler code3A 82 40 I D A,(16514) Return if ADD HL,BCFE 01 Cl' parameter 38 2B JR C,43D8 RET C it, t e r ° D I POP DE21 83 40 I D 11I,I651 5 Set CH-ADD_ ES PUSH H I22 16 40 I D 116408)

,,F11.

A7 AND ACD IC 11 CALL LOOK VARS Find array. ED 52 SRC HL,DED8 REP C Return if 44 I D OHCO RET NZ Il l in te tte 4D I D C, I7E A,IHI) Return El POP HIFE BO Cl' 128 I I E I EX (SP),HID8 RET C string Es PUSH H I23 INC H I Set A to 19 ADD I I I ,DE23 INC HI. number of 23 INC Ht.23 INC H I dimensions. CD 9E 09 CAI I . MAKE SPACE

I D AAHL) El POP HLCO 27 SLA,A Multiply by DI POP DE06 00 I D 8,0 two and 73 Lb CHL),ECB 10 RL B add one, 23 INC HI.3C INC A rimier 72 Lb (141..),D4F I D C,A to BC. 23 INC28 DEC HI. H I points to 23 INC H I56 I D DOLL) length. 4E Lb C-4.131.1211 DEC HI. DE is 23 INC HLSE LD EAHLI old length 46 LD B,(141-)E5 PUSH HI . Save 11 00 00 Lb DE,0D5 PUSH DE Ea EXE.13 EX DEMI, Set DE 3A 82 40 I D A

f( 1 65 1 4)

Al AND A to old 09 ADD HI ,BCED 42 SRC HL,BC data length 3D DEC AES EX DE,HL FE 00 CP 021 00 00 1.1) HI-,0 Calculate 20 FA JR NZ.,-6IA 82 40 I D /5,06514) new data EB EX DEJILAl AND A length 72 I D MI LD19 ADD HI ,DE 211 DEC HI3831 JR C,51 Jump on overflow 73 I D (111.),E3D DEC A C9 RETFE 00 Cr 0 El POP H I20 Et IR NZ,-8 El POP HL

C9 RET

'Table 2. A ZX-8I routine to enlarge an array dynamically.

There is no Basic command to makean array grow to fi l l the remainingmemory space and so I have written themachine code routine listed in table twoto do the job. The routine can be loadedinto a REM statement forming the sec-ond line in a ZX-81 program using ahexadecimal loader. For example:10 REM XAS20 REM AT LEAST 108

CHARACTERS30 FOR 1=16523 to 1663040 INPUT ZS50 IF ZS="S" THEN STOP60 PRINT Z$;" " ;70 POKE I,16*CODE Z$+ CODE

ZS(2)-47680 N EXT 1

To load the machine code routine,run the loader and enter each pair o fhexadecimal codes i n turn. Be verycareful not to make mistakes becausethe program makes no error checks.

To use the routine to double the sizeof a string array called AS make the firstprogram line a REM statement contain-ing an "X " followed by the name of thearray, i.e., AS as in the loader. ThenPOKE the factor by which you wantthe array to grow into the first byte ofthe REM statement. In that case thearray is to grow by a factor of two so youshould enter:POKE 16514,2Then call the machine code routine byentering:RAND USR 16523

CommentSet H I tonew kngth,

Set BC toincreasein length_

Set HI toaddress ofcod of array.

Enlarge amay.

i n te t t n e w

length.

Set BC toIltstdimension.Calculatenew rustdimension.

Store newfirstdimension.

If overflowthen return.

Both the total length of the array andthe size of the first dimension will growby the factor specified at address 16514.

The routine makes a number of errorchecks. It will detect i f the named vari-able does not exist or is not an array. Italso ensures that there is sufficient roomin RAM to enlarge the array by thefactor specified.

The routine makes use of two ROMroutines. Th e fi rst i s LOOKVARSwhich is located at 4380 decimal -W C hexadecimal.

That routine finds the location in thevariable area of the variable pointed toby CH-ADD and returns the address inthe HL register pair. The second ROMroutine, MAKE SPACE, inserts BCbytes at the address pointed to by HI..

The operation o f the routine can bechecked by adding the following lines tothe hexadecimal loader:1000 D IM A$(2,3)1010 L ET AS(1)="ABC"1020 L ET AS(2)= "DEF."1030 GOSUB 20001040 POKE 16514,21050 RAND USR 165231060 CTOSUB 20001070 STOP2000 L ET W =PEEK

16400 + 256'164012010 FOR IXIV TO W+212020 PRINT I,PEEK I2030 N EXT I2040 PAUSE 327682050 CLS2060 RET URNExecute the test program by entering:RUN 1000

The program declares an array ASand PRINTs the contents of the first 22bytes o f the variable area where thearray is held.

The user can note the contents of thedisplay and compare it to the format ofan array as shown on pages 173 and 174of ZX-81 Basic Programming.

The program then doubles the size ofthe array and displays the first 22 bytesagain. The user will see that the totallength of the array has increased appro-priately and that the size o f the firstdimension has doubled.

With a little care the routine can beadapted to run on the Spectrum. TheROM routines L OOKVAR S a n dMAKE SPACE are located at .10418and 5717 respectively. CH-ADD is at23645 — 5C5D hexadecimal.

It i s also necessary t o alter theaddresses at which the scale factor andthe name of the array are stored.

112

ISINCLAIR USER Annual 1984

FOOTBALL POOLSPROGRAM

• The program lists out, in order of preference. the sixteen mostlikely score-draws: also the sixteen most likely homes_ drawsand away&

• I t picks Out t he results on t he bookmakers FI XED ODDScoupons that have been given over-generous odds Calc ufates your expected profi t,

• The program will b e initialised t o the English and Scottisheague tables You will be able to update these league tables•••••eeh by week as results come in — or enter a complete new

set of league tables in other words, the program will neverbecome ' Out ot da t e- ,

• Al l programs are recorded on a top quakty cassette (usuallySony) and are accompanied with an instruction leaflet giving abrief explanation of the theory

Available for the ZX-81 16K (Price £8.95) and theZX Spectrum 48K (Price £9.95) from:

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fl YES, please enrol me as a member of' the exchangeclub. I enclose my £4 cheque/postal order.I also enclose l ta p e (s) fo r exchange, please send methe current availability list and exchange voucher(s)(f1.45 per exchange).

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(Combined Price £35.00)

£25.00E25.00

SALES AND PURCHASE LEDGERSProduces day book, salespurchases and VAT analyses.debtors/creditors list ings and statements. 250 accounts and1000 monthly transactions_ Automat ically calculatesVAT.

ZX-131 16KACCOUNTS PREPARATION31 nominal ledger accountsSole TraderLimited Company

(Combined Price £25.00)

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113

Number crunchon Sinclair

AQUESTION often posed by

those writing an educational pro-gram who have incorporated a

number of problems into their programand want to present, say, half of them inone session, is asked by Steven Maltbyof Northampton. How do you tell theZX-81 t o th i n k o f fi ve randomwhole numbers between I and 10without the risk o f repetition?

The obvious answer to his question isa routine of the form:10 D IM A(5)20 LET A(1) -= I + INT(RND*10)30 PRINT A(1),";40 FOR I =2 TO 550 L ET R = 1 +INT(RNDIO)60 FOR I = 1 TO I-170 IF A(I)=R THEN GOTO 5080 NEXT I90 L ET A(I)– R100 PRINT A( I) ;" ;110 N E X T!

Array A is used to store each selectionand i f a repetition arises it is discardedand a fresh random number is drawn.The routine works well for small sam-ples but becomes progressively slower i fthe number of samples is increased.

To see the effect, try changing lines10, 20, 40 and 50 as follows, to simulatethe effect of drawing all 52 cards from apack in random order:10 D IM A(52)20 LET A(1)=1 + INT(RND*52)40 FOR 1 2 TO 5250 LET R= 1 + INT(RND*52)

Each selection tends to take longerthan the previous one because thechance of choosing a number which hasappeared previously increases. In choos-ing the final number, the ZX-81 mustselect the correct number out o f 52

5 LE T A• 110 PRI NT "BYTE"; TAB 6;

"CONTENTS"; TAB 16;"CHARACTER"

IS LE T 5= PEEK 23635+256*PEEK23636

20 FOR I -S TO 5+2025 PRI NT 1;TAB 8;PEEK 1;TAB

20,CHRS PEEK 130 NE X T ITable 1 . A Spectrum pr ogr am whi chlooks at the first 21 bytes of the programarea.

possibilities, which can take a very longtime.

A much more elegant solution is touse a routine which mimics the act o fshuffling a pack of cards, 1,e., create anarray containing all 52 possibilities inorder and then randomise the locationsof each element of the array in turn. Asuitable routine o f th is fo rm f o rMaltby's problem is:10 D IM A(10)20 FOR I= I TO 1030 L ET A(I)= I40 N EXT I50 FOR I= I TO 1060 L ET R I + INT(RND*10)70 L ET S A(R)80 L ET A(R)=A(1)90 L ET A(1)=-S100 NEXT I110 FOR I = 1 TO 5120 PRINT A(I)130 N E X T !

Lines 10 to 40 set up the array, lines50 to 100 swop each element in turnwith another element selected at ran-dom — the equivalent of shuffling cards— and lines 110 to 130 PRINT the firstfive elements of the randomised array_

Alan Sheldon o f Aylesbury asks: I twould appear that numbers in theprogram area o f memory are fol-lowed b y addit ional informat ionwhich does not appear in listings. Isthat so and if so why?

Sheldon is correct as can be seen byentering the Spectrum program listed intable one. The program will also workon the ZX-81 i f line 15 is altered toread:

15 LET S=16509Line 5 is a dummy line, the purpose

of which is to allow the user to study theappearance o f numbers i n programs.When the program is RUN i t looks atthe contents of the first 21 bytes in theprogram area and displays them on thescreen. The results for the Spectrum areshown in table two.

The first two bytes contain the linenumber (5) and the next two bytesspecify the length o f the remainder o fthe line (11 bytes). The next four byteshold the character code for the first lineof the program:

LET A= I

The character codes vary slightly be-tween the two machines. For example,the code o f the letter 'A ' is 65 on theSpectrum and 38 on the ZX-81 al -though the code for the 'LET' is 241 onboth machines. The full list of charactercodes is given i n appendix A o f themanual supplied with each computer.

On the Spectrum the next byte con-tains 14. That is not the code for theend of a line, as might be expected, butinstead it is described in appendix A ofthe manual as "number". In fact, thebyte acts as a signal to the L IST andother commands to ignore the byte andthe contents of the five locations whichfollow it. Hence there is no indicationin listings o f the program that thoseadditional locations are used. The lineis terminated by the next byte whichcontains 13 — the ENTER character.

On the ZX-81 the character codes aredifferent but the effect is the same. Thelocation containing the code for 11 ' i sfollowed by six "hidden" bytes, whichdo not appear in program listings.

Some clue as to the purpose of thosehidden bytes can be gained by replacingline 5, the dummy line, by another line.Try, for example, RUNning the pro-gram with

5 L E T A –2.7as the dummy line. The characters forthe number "2.7" occupy three bytes,not one as for the number " I " , butagain the number is followed by sixhidden bytes. A few minutes' experi-mentation wi l l show that whenever anumber appears within a program sixhidden bytes follow_

The reason for the use of the hiddenbytes is that the ZX-81 and the Spec-trum do not store and manipulate num-bers in the character form in which theyare displayed_ They are converted into a"calculation" format and all additions,multiplications and so on are undertak-en on the numbers in this format, When

Byte C o n t e n t s C h a r a c t e r237552375623757237582375923760237612376223763237642376523766237672376823769

05110241656149140010013

LETA

Table 2. The rtrst 15 lines of the screendisplay pr oduc e d w h e n t h e S pe c t r umprogram in Table 1 is executed.


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116

the result °fa calculation is PR1NTed itmust be converted into characters fordisplay on the screen. Similar ly , thecharacter form of a number entered bythe user must be converted to the calcu-lation format before a calculation can beexecuted.

All such conversions take time. T oaccelerate the execution of programs theconversion to calculation format is un-dertaken immediately a number i n aprogram line is entered from the key-board. The resulting five-byte form isstored in the hidden bytes. The use o fthis technique enables a considerablesaving to be made in the time taken toexecute a program, particularly i f num-bers are included within FOR loops, inwhich case the same conversion wouldotherwise be undertaken many times.Of course, the time taken to deal with aprogram line entered from the keyboardis lengthened but not to an unaccept-able extent.

Hugo Cassidy o f Dorchester asks:Can you explain the method of en-coding numbers on the Spectrum?

Given that it is necessary to convertnumbers from decimal to binary, i t islogical to use a binary format which isefficient and therefore fast for the com-puter to use. Two separate formats areused on the Spectrum, a special tbrmatfor integers, or whole numbers, ly ing inthe range —65535 to 65535 and a float-ing point format for all other numbers.The ZX-81 uses the floating point for-mat only.

The integer format is the simplest tounderstand and so I shall explain it first.A suitable number, N , is converted tothe five-byte form by setting the fi rstand fi fth bytes to zero and using thesecond byte to indicate the sign o f thenumber, 0 for positive, 255 for nega-tive. I f the number is positive the valueis stored in the third and fourth bytes as:

Third byte= N- 256*INT (N1256)Fourth byte = INT (N1256)

I f N is negative the two bytes contain:Third byte =65536—N-256*

10 I NPUT N20 PRI NT N;" ";30 LE T A = PEEK 23627+ 256•PEEK

2362840 EOR I .,A + I T O A+ 5

50 PRI NT PEEK L" ";60 NE X T I70 GOTO 10

Table 3. A Spectrum program to inspectthe five-byte form of number entered bythe users.

To run the program on the ZX-81 changeline 30 to read:30 LE T A = PEEK 16400+ 256•PEEK

16401

IN T ((65536—N)/256)Fourth byte= INT 465536—M1256

The principal advantage of the use ofinteger format is that for positive inte-gers the third and fourth bytes are in theform the Z-80A microprocessor useswhen addressing locations in memory.Commands such as PEEK and PO KEare executed muc h faster than theywould otherwise be if the more complexfloating point form were used to storethe addresses to which they refer. Theformat also enables the calculator rou-tines in the ROM to execute much morequickly when calculations involving in-tegers only are performed.

The program in table one can be usedto inspect the positive integer form byvarying the fi rs t line. F o r example,entering:

5 L E T A- 4 7•will show that 47 is held as 0,0,47,0,0.The negative version cannot be inspect-ed using this program because all num-bers are stored in their positive form inthe hidden bytes. I f a number is preced-ed by a negative sign it is negated whenthe line is executed.

The program in table four gives thefive-byte form o f any number, positiveor negative, entered from the keyboard.The program PRINTs the contents o fthe first item in the variable area, that isthe number N entered by the user fromthe keyboard, because i t is the fi rs tvariable declared in the program.

Note that t he program should beinitiated by entering RUN rather thanGOTO 10 because doing so will causethe variables area to be CLEARed, thusensuring that N is the first variable.

The fl oating point form is designedto provide the computer with a system-atic method of retaining as much accu-racy a s pos s ible i n a n y g i v e ncalculation. Some numbers cannot bespecified completely in decimal form.The fraction one-third in decimal formconsists o f 1.3 followed by an infi nitenumber of threes so that expressing it as1.3333, for example, is almost, but notexactly, correct. The same problem oc-curs when binary arithmetic is used.

The solution is t o retain only themost significant digits at each stage in acalculation. Provided more significantdigits are retained than are required inthe answer then in a l l but the mostexceptional circumstances the calculat-ed result w i l l be accurate enough forpractical purposes.

The program listed in table five cal-culates and PRINTs the floating pointform o f a number entered by the user.The line numbers have been set so thatit can be placed in memory at the same

time as the inspection program in tablefour. By entering the same number intoboth programs the user will see that thecalculation is correct.

The program has two parts. The firststores the sign, S, o f the number, X ,entered by the user. I t then multipliesthe absolute value of X successively by2 until the result exceeds 2 raised to thepower 31 or 21474383648. The numberof multiplications executed is stored inN. The new value of X then lies neces-sarily between 2 to the power of 31 and2 to the power 32 and so the integer partof the number can be stored exactly in31 bits.

Thus b y discarding the fractionalresidue the number can be stored infour bytes, each containing eight bitswith one bit left over to hold the sign ofthe number. The four bytes together arecalled the mantissa.

The second part o f the program cal-culates the values held in each o f thefour bytes and stores them in the varia-bles A, B, C and D and then PRINTsthe variables. An adjustment is made tothe value of A depending on the sign ofthe original number. In effect A is lessthan 128 f o r pos itive numbers andgreater or equal t o 128 for negativenumbers.

The fi fth byte o f the fl oating pointform is used to store the exponent, thatis the number o f times that the mani-tissa must be divided or multiplied by 2to place the decimal point in the correctposition in the number.

The program calculates that numberusing N, the number of multiplicationsmade originally. The result is adjustedby adding 160 so that numbers greaterthan or equal to 128 and numbers lessthan one have exponents less than 128.

210 LE T N••0220 I NP UT X.230 LE T S . .,S G N X240 LE T X • ABS X250 LE T X • 2•X260 LE T N= N+ I270 I F X <2147483648 THE N GOTO

30280 LE T A.• I NT (X116777216)290 X. .X-16777216*A300 LE T B = INT (X165,36)310 LE T X=X-65536•B320 LE T C= INT (X1256)330 LE T D•. •X--256•C340 PRI NT "EXPONENT. . ' ; 160—N350 PRI NT "MANTI SSA•";A•

128(S= 1);" ";13i" ";1:;" ";13Table 4. A Spectrum program to calcu-late and PRI NT the floating point form ofa number entered front the keyboard.

SINCLAIR USER Annual i984

Userof the Month

During the last 12 months we began a newseries in which we interviewed interesting

users. We reprint some of them to indicatethe wide variety of purposes for which the

Sinclair machines are used.

SINCLAIR USER Anrmal 1984 1 1 7984

118

Stephen Sowerby is a member o f the Olympic pentathlon squad.Claudia Cooke discovers how he makes time for training

Leading athlete's quest forgold is boosted by ZX-81INTERNATIONAL athlete -Ste-

phen Sowerby swears by his ZX-81. Without it, he says, finding the

time to train is much more difficult. At28, Stephen hopes to make his Olympicdebut as one of the four-man modernpentathlon squad in the 1984 Games inLos Angeles.

On top of that, he runs two busin-esses near his home in Yorkshire andspends what precious spare time he hason his hobbies of photography and wineand beer making. He says:

"I'm impressed with the little beast— the ZX-81. I bought it last Decemberwith the idea of upgrading it as soon as Ihad mastered it but I don't sce any neednow. It does everything I want it to do".

Before b u y i n g h i s computer,Sowerby had had no contact with any-thing more complicated than a pocketcalculator but he decided that anythingwhich could speed his office workloadwould be invaluable.

"First, I waded through the book andmade it to work. Then I wrote my firstprogram, a simple one for VAT check-ing which has been fantastic. I foundthat i t was really easy i f you usedcommon sense. O f course, there wereheadaches along the way but I sat downand scratched my head and it all cameout right.

"I am pleased to say that I have neverbought a commercial program. I havewritten 10 of my own; the longest is forhelping me to do the accounts. T h eamount of time it saves is incredible. Ibuy the computer magazines and usesome of the programs in them. Apartfrom being fun they can be really help-ful, too, because sometimes you dis-cover you have been using five lineswhere someone else has discovered away to say the same thing in only oneline".

Running his business, as well as fit-ting in his sports activities, means thatSowerby i s highly:motivated t o d oeverything in as short a time as possibleand the computer has helped.

"If I have all my work done by areasonable time in the afternoon I canleave and fi t in more training. So thecomputer is helping me in my sport,

too" Modern pentathlon is a gruellingcombination of sports, the aim being tofind the best all-rounders. I t embracesswimming, running, fencing, shootingand show jumping.

"Swimming was always m y mainsport at school. I won at county leveland was in the national top 10 when Iwas 17. Then I went to Carnegie Col-lege, Leeds to train as a physical educa-tion teacher f o r three years and Istopped competitive swimming.

"My first job was as a teacher o fPE, swimming and outdoor pursuits atDaniel Stewarts and Melville College,Edinburgh, where David Wilkie wentto school. I thoroughly enjoyed it butafter a year I had the chance to swim

competitively again with my old club inLeeds and so I left teaching to givemyself more time.

"I was trying to be selected for theCommonwealth Games and that meantfour or five hours in the water everyday. Then I entered the national biath-lon — swimming and running. I hadentered it and won while I was still atcollege and that time I won it again".

Sowerby i s modest about t h a tachievement, saying that although hewas always the hest runner at school, heassumed that was simply because hewas fit from all the swimming.

The result of his success in the biath-lon was that the well-known pentath-lete, Jim Fox, suggested he should try


modern pentathlon. H e h a d nev erfenced before, never used a gun, andscarcely r idden a horse but after onlyfour weeks' training, he entered his firstpentathlon in Cambridge and finishedsecond, despite the presence o f seveninternational modern pentathletes.

Since then he has not looked back.He has risen to international status andtravels the world to compete in eventsas far afield as the United States—threetrips already—and several countries inthe Eastern bloc.

' 't love the travelling and there are somany places I know I would never haveseen had i t not been for the competi-tions there. We were in Poland at thestart of the crisis and I learned a gooddeal from that.

"They absolutely revere their sports-men. There were food shortages andqueues everywhere but we had meat atevery meal and the autograph hunterswere all round us".

Sowerby is the only member o f thefour-strong Olympic squad who doesnot train full-time but he sees that as nobad thing.

" I have all the practice I need and ina way I think my job helps, because ittakes my mind off things. I f you are justtraining all the t ime y ou think onlyabout your sport and it doesn't necessar-ily do you any good. You just becomebored waiting for the next training ses-sion.

" I am glad I tr ied the modern pen-tathlon because I am so much happiernow. You have to be good at all liveevents but if you don't do so well in oneaspect, it 's not the end o f the world.When I was swimming, one race mightmake or break me.

"Now I know I am the worst fencerin the squad but I am training hard andmy running and swimming are strongenough to compensate for it " .

The businesses which Sowerby runsstem from the enterprise of his parents,Dennis and Els ie, who formed theirjoinery company at Knaresborough 30years ago. As the business flourished, somore and more customers needed glass,so he formed Knaresborough Glass andnow runs both companies with the helpof his father.

Set in a small yard °lithe main streetin the sleepy Yorkshire market town,with offices in a building known as thehen hut, it is a far cry from the glamourof the international sports c ircuit butSowerby, who last year married a fellowmember of his swimming club, is happyto return to his hen hut and sit crouchedover his computer.

Since buying the ZX-81 he has also

bought an Olivetti printer driven by aMemopak I /F which he keeps hiddenunder the dK'tronics keyboard.

"The printer has been a marvelloushelp, too. I have written a word proces-sor program and I use i t for a ll myletters, for fi nal demands, invoices, ev-erything really. I begin to wonder whatI did without it " .

Sowerby also sees potential for com-puters in the wor ld o f sport. Alreadythey are used widely for results, as wellas for much of the administrative work,but he cites a need for them in sportssuch as fencing. Each fencer's sword

has a button on the end which lights atcertain points of contact with the oppo-nent and is controlled by a box mechan-ism. "That box mechanism often failsand as there is only one company mak-ing fenc ing equipment, there is notmuch we can do but a computer t ooperate that mechanism could prove farmore reliable and I am sure someonecould make money producing it " .

Sowerby feels the project is a lit t leambitious for him, although he main-tains that i f you want to do something,

you can usually do it even when, as inhis case, it seems as i f there will neverbe the time_

" I do a great deal with my time but Ienjoy it all, otherwise I wouldn't do it. Iwill go on as a pentathlete until I stopenjoying the training. When it becomesa real chore and you don't want to do it,that's the time to stop.

"Many people seem to think I mustbe sacrificing a great deal for sport but Idon't see i t as a sacrifice, because Ienjoy it.

"The only things I miss are smoking40 cigarettes a day and probably being

'I have written a word processor program andI use it for all my letters. For final demands,invoices, everything really. I begin to wonderwhat I did without it '

overweight by the age of 18. So where'sthe sacrifice?"

Financially, Sowerby has to be self-supporting in his sport and that canmean sacrificing some expense — theSpectrum, for example, for which hesees no need in his office but on whichhe loves play ing games for its colourand its extra graphics.

Any purchase not essential t o h imstays in the shop but that could be whyboth his business and his sporting ca-reer are proving so successful.

SINCLAIR USER Annual 198-1 1 1 9

1

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C O U N T I N G . ade 3 - 6 1 1 6 /4 8 K S p ec t ru m E 5.2 5

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• 11 graphics procedures• Hi- and lo-res sketch pads• 8 sizes of text• a mini-text editor• colour WASH and PAINT• create your own UDG characters• SAVE displays on tape or PRINT on ZX Printer• RELOAD displays into your own programssend E6.90 for cassette and manual*graphics software for ZXI31 also available*5end s a.e tor our lull list of games. Stat is t . graphozs and screnotc software'FuM rnonPy back guarantee Trade entwines welcome

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Address

121


Each month we will interview a notable Sinclair user. Claudia Cookemeets our first User of the Month, a retired shipbuilding manager.

Retiring to the sea, theships and his SinclairsERIC ANSELL had been looking

forward to retirement and thechance of a return to his native

Isle o f-W i gh t . Two years ago, at the age of

65, he moved into a cottage near the seaat Cowes with his wife, also an islander,and intended to enjoy a quiet life ofraiding, walking and watching television.

"Never in a million years did I think Iwould learn something so new at myage", he says. Yet in the six months sincehis son gave him a ZX-8I, he has becomehooked on home computers, to the extentthat he has just bought a Spectrum and anew tape recorder to go with it.

"My son bought a ZX-8I but then hemoved to another computer and when hevisited me last summer he asked i f Iwould like the ZX-81.

"At first I wondered what I wantedwith a computer. I could not see any usefor it. I had no interest in computers and Idid not realise how much fun they couldbe".

Ansell, however, is a man who believesin trying anything. "Once my son hadleft I started fiddling with it and becameabsolutely hooked in no time. It is thesheer logic of it which appeals to me," hesays.

"You program a game from one of thebooks and it tells you that you have madetwo errors. Once you find those errorsyou realise they are so logical andobvious. It just takes common sense".

He admits it was two weeks before hemanaged to program a game successfullyand he has not yet reached the stage ofwriting a program.

"When I bought the Spectrum twomonths ago. I found it much easier tostart because I already had someknowledge of the ZX-8I and I havebecome much faster at typing-in now.

"I used to have two pipes of tobacco inthe afternoon and perhaps read a little orwatch television. Now I become soengrossed I forget all about my pipe andeverything else and I usually spend abouttwo hours, four days a week, with mySpectrum".

Ansell had had contact with computersduring his work as naval planningmanager with Swan Hunter in Newcastle


before his retirement but although he didthe critical path diagrams for thecomputer printouts, his contact wasindirect.

"I was always rather dubious aboutlarge computers at work. If, for instance,something is proceeding satisfactorily ona ship and you put i t through thecomputer to find the best way, you mighthave to wait five or six days for an answerbut you can go and look at the ship andhave it corrected in one day".

He Spent 35 years working for a localshipbuilding fi rm a t Cowes beforemoving to Newcastle when the firmclosed. He began his career as a navaldraughtsman and then became a char-tered engineer before working as a navalshipbuilding manager. He loves shipsand everything to do with them and says:

"What amazes me about the Spectrumis its ability to produce an almost perfect

'Never in a millionyears did I ilLink

I would learnsomething so new

at my age'reproduction ot, say, a destroyer, at thepush of a few buttons".

Ansell is keen to scotch rumours thatcomputers arc for the young, or at leastfor the under-60s. He sees no reason whythat should be so.

"I admit we are not so likely to havecontact with them in retirement. I doubtthat I should have discovered them if ithad not been for my son but I wouldstrongly advise any retired person with areasonable amount of common sense tobuy one straight away and play with it.

"It has given me an interest I neverexpected to have at my age and mybrother-in-law and I spent the whole ofBoxing Day together, playing golf withthe Spectrum".

It must be said that he is and always hasbeen an avid games player. Apart frombeing a crossword fanatic, he alsosubscribes to a weekly puzzle magazine

and likes board games as well."I remember when my two sons were

young, I would buy a new game everyChristmas and we would all spend hourswith it, sometimes making-up the rules aswe went along which, of course youcannot do with a computer", he says.

As for progressing to even moreambitious activities, he is happy with hisZX-8I and his Spectrum, although hesays he may consider a 48K Spectruminstead of his present I6K.

The next step, of course, is for him tobegin writing programs, something he ischaracteristically keen to try.

"I realise I need more experience firstand I am still enjoying the cassettes I canbuy, like Escape and Othello, but I wouldlike to program one or two games and Iintend to try soon. I find a great sense ofachievement in putting a program ontape and having it correct".

Ansell is a young-looking 67. He wearsa smart blue velvet jacket and sits in anarmchair within easy reach of a bowl ofassorted pipes, as befits any ocean-lovingman. On the other side is his Spectrumand across the room there is thepresentation tray he received on hisretirement from Swan Hunter, listing allthe ships on which he worked.

The room is a stark mixture of the oldand the new, a combination which Ansellhas proved can work well together. All inall, computers have enhanced his life in away he did not think possible and did notthink he desired.

Retirement at Cowes, where he and hiswife were brought up, attending the sameschool and marrying 43 years ago, issomething of an idyll and Ansell admitsthat much as he enjoyed his years inNewcastle, there was never any doubt inhis mind as to where he would set up hisretirement home.

"I think that had I left the island when Iwas young, there might not have been thesame nostalgia but I was SO when wemoved north and that is just too old tobegin putting down new roots".

Now, surrounded by sea, ships and ahost of books on both subjects, Anselland his computers are enjoyingthemselves thoroughly.

123

Claudia Cooke interviews a West Midlands doctor who is findingways of using a Sinclair computer to help educate his children

The smiling Spectru

SOPHIE DENT has found 'lie

enriched since the arrival o f aSinclair Spectrum in her home

six months ago. I t is not that she hasspoken of that enrichment but speakingis altogether a problem, since Sophie isonly 18 months old.

Her shrieks of delight are sufficientproof as she hurls herself towards thekeyboard for another intense sessionwith -one o f her two programs. Bothwere written specially for Sophie by herfather, D r Tom Dent, who shares So-phie's enthusiasm for home computers.

His other children, 10-year-old Jamesand Rhian, aged seven, both fell in lovewith the Spectrum as soon as it arrived.It soon became apparent that the role ofonlooker was too much tbr little Sophie;she wanted to play, too.

At first her father was not sure howhe could write a program for Sophie—for pressing specific keys and refrainingfrom resting an elbow on the others isdifficult for any baby—but found theanswer with two colourful and instant-ly-rewarding programs which operatewhichever key is pressed.

The first allowed Sophie to produce asmiling baby's face on the screen, some-thing with which she could identify andrecognise from an early age. Her father,a 35-year-old general practitioner, ex-plains: -F a c es a re t he fir st things to

which a baby responds and under-stands. It was a happy, smiling face andSophie loved i t-.

The second baby-proof program iscalled Ghastly Graphics and has provedequally popular with the older children.Again, it operates by random pressingof the keys. Gradually i t produces amass of random graphics which eventu-ally will t ill the screen in a colourfulpattern. Each graphic is accompaniedby a note, making a cheerful tune whichfurther captures Sophie's attention.

Dent admits that at that stage theSpectrum is just another toy to Sophieand an expensive one were it not alsoused by other members of the family.

He is already looking to the future,when Sophie is three or four, and hopesthe Spectrum will be able to teach her to

read quicker and more efficiently thaneither he or his wife, 36-year-old Janet,could do.

"The marvellous thing about a com-puter is that i t has infinite patience.Where anyone else might be bored witha reading lesson after half an hour or so,it will carry on until Sophie has hadenough; and when children are reallyinterested in something, they can go onfor hours.

"The computer also makes thingsmuch more fun; learning becomes agame. I have written two educationalprograms for James and Rhian and theylc,ve them. Yet i f I showed them thesame facts in a book they would tell meto get lost. Books do not tend to befun".

One of Dent's educational programsis for learning tables, a tedious task formost schoolchildren. Yet James and his

friend both worked their way throughthe program during my visit with evi-dent enjoyment, not to mention greataccuracy.

The other program is on elementaryphysics, an explanation o f the differ-ences between gases, solids and liquids.A simple explanation of each is followedby a simple question to test the child'scomprehension o f what has just beenread. A n incorrect answer takes the

is Sophie's first choicechild back to the relevant text, whichmay be read again for a better under-standing.

There arc no pictures, no tunes—only words. Yet the program has provedpopular with the children in a way nophysics text book could hope to do.

"I f you want to know the answer in atext book, you have to look it up eachtime at the back of the book but here ittells you immediately whether you arecorrect_ It also means you cannot cheator skip pages as you can do in a book. Itis programmed so that you cannot moveon until you have understood and an-swered a question correctly on one par-ticular section".

The Dent family does not use theSpectrum only for serious programs.They use many of the games programson the market, too, and Dent was forcedto admit that he is usually beaten byJames.

He sees the implications of the com-puter generally as far-reaching. Alreadythe health authority at Walsall, wherehe works in a group practice, has acomputer which can recall children forvaccinations more accurately than hu-man labour could do.

There is also the potential for com-puters to be used in many other formsof recall in medicine, such as womenneeding regular cervical smear tests.

Dent feels that i f individual practicescould have their own computers theycould prove invaluable in assessing indi-vidual practitioners' performances. l i ehas already written a Basic program asan experiment for patient use. I t as-sumes that the patient is complaining ofa stomach pain and asks a series o frelevant questions to which the patientresponds by pressing a key.

The computer assimilates the variousresponses s o that D e n t can pressanother key and be given one or severalpossible diagnoses.

I was invited to try the program and,being unable to remember the full de-tails of any stomach pain I might havehad, caused a rather confusing diagnosiswhich ranged from dyspepsia to gallbladder trouble. The point was that it

124 S I N C L A I R USER Annual L984

1was f u n and I th ink I would havethought so even i f I had a pain at thetime. I t also seemed more private and Icould take my time in pinpointing theexact spot of the pain without worryingthat the doctor might become impa-tient.

The program is not something Dentwill use with his patients; it is simply atest for himself at this stage.

" I think a computer could becomevery useful i n this fi eld. Certainly i twould save some time i f a patient wereto answer the questions before going into see the doctor. I t is a fact that adoctor, being only human, cannot askthe same questions without some formof bias.

With a computer, a patient is givenno hint o f an expected answer, or thepossible element o f surprise a t anygiven answer, but Dent is quick to pointout that the computer is not in itselfsufficient because i t does not see thepatient.

"The computer cannot possibly no-tice that the patient looks more tiredthan the previous week, for example, orseems to be depressed about something,but it might have a function in produc-ing, very quick ly , a l is t o f possiblediagnoses for a given complaint".

Dent, who lives with his family andhis Spectrum at Streetly, near SuttonColdfield in the West Midlands, trainedas a doctor in London and has been

practising at Walsall for five years. Oneor two o f his friends in the area havetheir own home computers but he sayshis children know more computer own-ers than he does.

"By and large, children seem to lovethem, I f they think a computer is funand it helps them to learn, I cannot seeanything wrong. I certainly do not feel

'The computer alsomakes things muchmore fun; learningbecomes a game'

it is indoctrination or anything. When achild becomes bored with the computer,he has only to switch i t o f f and walkaway".

Dent is hesitant about predicting thesuccess of a computer as a replacementfor school because of the social implica-tions.

" I t is a good teacher but I think thechildren wou ld mis s school fr iends ,football and so on. We hope that Sophiemight learn from the computer to readand perhaps to write before she beginsschool.

" I f there were no school in the areawhich seemed acceptable to us, I sup-pose we might consider teaching her athome but that is not t he case and,

anyway, I think we would make thatdecision w i t h o r w ithout t h e c om-puter".

At the moment the Spectrum is So-phie's toy , one o f many. She under-stands that w press a key w ill producesomething entertaining on the screen.She does not yet know that it can make adifference which key you press and shecertainly does not understand that tapeswere not designed for unravelling witha lit t le linger and trailing across thefloor but given that she is s till a baby,her familiar ity w ith computers shouldmake all those things far easier to learnin the next few years.

Her seven-year-old sister already en-joys entering programs, with a child'sunquestioning acceptance of the repet-itive details required in instructing acomputer—and s he started on ly s ixmonths ago.

The Dent family has found a toy, ateacher and a potential secretary all inone. The next stop w il l be to buy aninterface t o enable them t o use theSpectrum as a word processor.

With an age range spanning one-thirdof a century, they have found somethingfrom whic h each can benefi t. As afamily they have been converted.

If readers would like to ISOMIld ft people for Userof the Month, please write to Sinclair User, 196-200Balls Pond Road, London NI 4AQ :wing name,address and daytime telephone number and thereasons for the nominatton.

SINCLAIR USER A n n u i l 1984 1 2 5

1

button. I be tw o numbers are i nen setecteaon a pair of leads which are clipped onto' K E Y FEATURES , . .appropriately num ber ed strips on the inter- * P r o g r a m m a b l e d e , Ig r i g i v e s T O T AL s o f t-

face, w a r e support.Once confi gured this can be m ar ked on a * Ac c e pts Atar i , Com peti t i on Pr o. Wico,Quick Refer ence Pr ogr am m ing Ca r d f o r S t a r fi g h t e r , Quick Shot. Le Stick etc.storing wi th the game. As the programming * R e a r extension connector for al l otheris not power dependent the interface retains a d d - o n s .the last configuration made and can beimmediately used when next switched on. * F r e e demo program and instructions.

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,OUR INTERFACE20. Commodore (4,

400. Atari BOOJoysticks for our

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CITY ITEM ITEM PRICE TOTALPROGRAMMABLE INTERFACE 33.95JOYSTICK(S) 7.54PACK(S) QUICK REFERENCE CARDS 1_00

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ABOUT OUR I NTERFACEI he AGF Programmable Joystick Interfacea unique design offer ing the use of any Atari-compatible joystick wi th absolutely all software, w hether i t is cassette or R O M car t-ridge. wi th the Sinclair Spectrum or ZX81.The har dwar e programmable inter face r e-quires no additional software and accuratelyreplicates the keys o f the com puter i n amanner w hi ch i s responsive t o absolutelyALL key reading methods, both BASI C andMachine Code.The inter face does not inter fere w i th keyoperation a nd can therefore be used simul-taneously wi th the keyboard.There is no need to remove the interface oncefitted as the rear extension connector willaccommodate fur ther expansion, i.e printersor R A M packs etc. Thi s im por tant featureavoids excessive wear to the expansion por t.The key repl ication pr inciple pioneered byAGF means that your own programs can useeight di r ecti onal j oys t i ck m ov e m e nt b yutilising simple key reading BASIC.Two joystick sockets ar e pr ovi ded w hi c hshare t h e sam e keys , f o r us e w i t h t h emajonty of tw o player games. Several inter-faces may be used on the same computer formultiple joystick applications.The interface is programmed by a tw o digitcode, which is looked up on a programmingchart supplied, for each direction and fi r i ng

126

PACKAGE CON TENTS SUPPLIED• Pr ogr am m able Inter face Modul e as

trated, com plete w i th cl ip-on pr ogr amming leads.

• S e l f adhesive programming chart detailinghow to defi ne which key is simulated byUP, DO W N, LE FT , R I G HT, and F I R LThis can be fi xed on to the case of yourcomputer or i f preferred the protectivebacking can be left on. The chart is madeof a very durable reverse pr inted plasticand is extremely easy to read.

• O n e pack o f ten Q ui ck Reference Pro-gramming Cards for at-a-glance settingto y our games requirements. The cardallows you to mark the confi guration inan easy t o r ead fashion w i th space t orecord t he software ti tl e and com panyname,

• V i d e o G r affi ti dem onstr ati on pr ogr amwhich is written totally in BASI C to illus-trate how al l e i ght di r ections a nd fi r ecan be read. I his is also a useful hi ghresolution drawing progra 111.

• 1 2 m onths guarantee a nd ful l w r i tteni n s t r u c t i o n s , .

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127

128

Taking the strain out ofcalculating the wages

Starting with the ZX-80 Ronald Sims has always found serious usesfor his machines. Claudia Cooke talks to him about how they help.

NO-ONE was more pleased than

Vera Sims when her husbandRonald invested i n h i s fi rst

computer, a ZX-80. For the first time inalmost 20 years, her workload was re-duced from a day-and-a-half each weekto only four hours. Mrs Sims has thejob of calculating and paying the weeklywages for the 35 employees of the fam-ily automation business.

" I-used to do it all in my head, with

the help of a ready reckoner and it tookme a day and a half. Now my husbandhas written a program which does it allfor me and i t takes a few hours. It hasbeen marvellous".

Her husband has since changed to aZX-81 with a 64K Memopack and theprogram covers job costing for up to 10jobs, tax deductions, a variety o f indi-vidual allowances and more than 30subtotals and totals.

Mrs Sims, 69, says: " I t was a b i tstrange at first because I didn't knowthe first thing about computers but I

soon got the hang o f it and now I 'mreally pretty quick".

Husband Ronald, 70, interrupts toreveal that the early days were not thatsimple. "She just wouldn't believe it atfirst. When the computer produced thefigures she used to take them down

'The computer justcannot make the kind

of human errorseveryone makes'

quickly and work it out herself to makesure. I must say her calculations were asquick as those of the computer.

"Now she realises that the computerjust cannot make the kind o f humanerrors which every person is bound tomake at some time or another".

Although the Sinclair is his first com-puter, Sims i s no newcomer to theprocesses o f logic involved. H e had

worked in the radio industry since 1929and had become fascinated by 'wire-lesses' even before he left school at theage of 17.

"At school we had a physics masterwho was very keen on the wireless, as itwas known in those days. I was chargedwith his enthusiasm and by the time Ileft I was one of few people who knewhow they worked."

His first job was with a firm sellingdo-it-yourself wireless k i ts . Peoplewould buy the kits on Friday, he says,and return on Monday to find whatthey were doing wrong. His job was toadvise customers exactly how to assem-ble them.

"In the early 1930s I realised mytechnical education was not keepingpace with the changes so I got a job withSiemens in telephone exchange devel-opment work. The logic then was thesame as the logic o f computers todayand I was given a good training".

When the second world war broke

SINCLAIR USER Annual ISVPI

1981

out, the company had just begun workon the development o f radar and Simsbecame chief of test gear.

"There was such urgency because ofthe war that we had to start manufactur-ing in quantity products which had notbeen made previously. Being respon-sible for testing, i t was the first time Ireally became interested in automationand automatic testing."

After the war, Sims left to join Mi-chael Sobell, first as technical assistantto the buyer and then as chief buyer. Hestayed with the company for 12 yearsand says that without Sobell's commer-cial guidance he could never have start•ed his own business.

Start i t he did, 25 years ago, when hedetected a gap in the industry for auto-mation. Today his company, LectromecControls, is sti l l flourishing in southLondon, run b y his three grown-upsons and his ZX-81.

He is working on a cashflow programfor the fi rm, although he is doubtfulwhether his Memopack can cope with asufficient number of invoices.

His wages program to o k manymonths to compile but the result hasbeen worthwhile. Not only does i t dothe job much faster, i t rules out thenecessity for Mrs Sims to have her cashsheets checked by someone else beforehanding-out the pay.

" I f you make a mistake you just lookat the picture and know i f it's right orwrong", says Mrs Sims. "Th e onlything is that you lose your brain, be-cause you just look at the picture andcopy it all down. I used to have to makeso many calculations in my head butnow I almost think you could becomebrainless within a few years."

Sims has one criticism o f Sinclair,levelled at the printer. " I think i t wasvery ambitious to produce this printerbut I think it leaves a lot to be desired.It prints so badly; I think it's the ther-mal paper. I f you leave i t switched on

'I think it was very ambitious to produce theprinter but i t leaves a lot to be desired; i tprints so badly. I f you leave it switched on allday the thing gets warm and the print blurs.'all day, which we might need to dooften, the whole thing gets warm andthe print blurs".

On the whole, though, he sees hiscomputer as a great boon and not onlyfor work purposes. " We have fourgrandsons and you should have seenthem with all those computer games at


Christmas. W e couldn't drag themaway from the set. We all enjoyed i t".

The eldest grandson, aged 12, hasalready had the ZX-80 bequeathed tohim, together with the 16K memory.

as enthusiastic as hisHe is a t leastgrandfather.

Now Sims is working on a conversa-tion program to use with his grandsonsat this year's Christmas gathering. It isa marvellous program• so far, tailoredindividually to each of the four boys sothat i f one gives the computer his name,it is liable to answer back with the nameof his brother.

A selection o f 10 answers to eachresponse from the boys appears at ran-dom, resulting i n some highly-enter-taining non sequiturs, as well as somestartlingly accurate replies.

When asked how I was feeling by thecomputer, I replied "very hot", only tobe told rather cheekily: "You look allright to me". When I agreed with thecomputer's suggestion, " I hear they callyou Podge", i t replied curtly. "Stopmucking me about".

Sims hopes to develop the program toaround 10 or 15 minutes by Christmasand is gaining evident enjoyment from

the work involved.Aside from the computer, he and his

wife are kept busy at their home i nEwell, Surrey. Mrs Sims is a regularbowls player, although sadly out o faction during my visit due to a backinjury. Her husband likes nothing bet-ter than to sit down for an hour or so

and play the organ. He is from a musi-cal family and as a child learned to playa variety o f instruments, including thepiano, violin, flute and piccolo, but hisfavourite remains the organ. " I particu-larly love playing classical music. 1 havealways found i t relaxing. T o returnhome and get lost in the music for atime is a wonderful way o f recoveringfrom work".

The Sims also have a narrow boat,moored on the Thames, to which theyretreat whenever possible during thesummer months to enjoy the sun andthe fresh air.

"Mostly we take i t on the Thamesthese days, rather than the canals, but itis a wonderful way o f relaxing. Youdon't have to arrange it all, in advance;you just decide to go and that's it. It's akind of freedom which is very valuablein business because, contrary to popularopinion, you cannot just take-off onholiday overseas whenever i t suits you.You never know what will happen untilthe last moment".

Both are now semi-retired and thefather figure wisely attempts to keep hisnose out o f the family business to agreat extent, leaving his sons to run i tthe way they wish to do.

" I never pushed them into i t , o rexpected too much o f them. They allworked for other firms for a few yearsbefore joining me but I must admit it ispleasant that they all wanted to join.Now one is the managing director, oneis sales director and the third is reallyinstallation manager".

One o f his sons has also become ahighly-proficient organist, playing in adance band. His father pours generouspraise on his talent.

Married for 43 years, the Sims are acontented couple, although not contentto sit back and do nothing. Theirs is anactive life, made more so by the adventin their home of the computer.

They certainly defy any theory thatcomputers are for the young. It was MrsSims who, having read Sinclair User,became the fi rst person to nominatesomeone for the ti tle o f User o f theMonth — her husband.

She nominated him not only for hiswages program but also for the fact thathe derives so much enjoyment and re-laxation from compiling the programs.His enjoyment of making the programs,she says, i s almost greater than hisenjoyment o f operating them i n hiscomputer and although she steers clearof programming, she has learned a newskill at an age when few women expectto do so.

129

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use (no replacement needed).* Only one two-position switch for simplicity of use (no loose

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Memory

Expanding memory on both the basic ZX-81and the 16K Spectrum is a major concern to

Sinclair owners. Stephen Adams reviewedthe expansions systems available for both

machines and the results are re-printed here.


132

Cheap is not nastyin memory packs

Stephen Adams examines the many ways o fexpanding the storage of the ZX-81.

THERE ARE so many ZX-8I

RAM packs around these daysthat it is worth looking at what

they can offer i n the way o f morefacilities.

First, a litt le explanation o f the ZX-81 memory map and R O M routineswould help in understanding the limita-tions of the ZX-81.

SinClair engineers, when they de-signed the ZX-81, did not expect thatanyone would need more than I 6 K o fRAM. So they took some short cuts inthe design which made it cheaper andeasier to access the R AM and RO M.One o f the them was t o restrict theupper 32K of the memory map to work-ing the screen and nothing else. T heother was that the ROM, which is only8K long, was allowed to repeat itselfthroughout the memory map unless theRAM was working in that area.

Those decisions allowed them to de-code on ly t he t o p t w o ADDRESSlines—A 14/A 1 5—to determine whetherRAM/ROM or R AM with DISPLAYwas on at any one time, the address lineA15 deciding whether the display wason or not and the display being on onlyin the top 32K o f memory and thusdividing the memory map in half.

The A14 address line div ided each32K section into two quarters, the bot-tom half of which was RO M and thetop half RAM. As they were the onlydecoding done inside the ZX-8I the I Kof R AM repeated its elf all t he waythrough the I 6K RAM section.

Mem or y m ap of the ZX-81

64K

48K

32K

32K

I6K

8K

OK

RAM for display—display file

RO M appears again

IK or 16K RAM

1K or ISK RAM

RO M appears again

True ROM area

When the I 6 K R AM pack is added,however, it is switched-off-by t h e u s e o f

the RAMCS line on the edge connectorand the R AM chips in the R AM packdo all the extra decoding necessary todivide the 16K section into indiv idualbytes.

To expand the memory above 16Krequired some special decoding in theRAM pack so that i t did not interferewith the display, which needs a repeatof the fi rst I 6 K o f RAM at 48K andabove in the memory map.

It also required that the R O M berestricted to the first 8K of the memorymap. T ha t was done b y us ing t h eRO,MCS line in the same way as theRAMCS was used on the 16K R A Mpack, Memotech was the first companyto produce a 56K R AM pack. Most o fthem are now called 64K packs but youcan use only 56K and that allows you touse 48K for Basic and 8K R AM wherethe ROM used to be, between 8K andI6K, for machine code.

There are some restrictions on usingthe 48K as you cannot r un machinecode in i t and you have to be carefulthat the display fi le does not cross the32K border. Memotech now has 16Kand 32K RAM packs in the same boxesas its 64K ones, which are often used bydealers as a second choice to the SinclairI6K RAM. Memotech has a good repu-tation for service. The 32K pack allowsyou to use your 16K RAM pack as wellto achieve 48K.

The boxes are made from extrudedaluminium and are used as a heatsinkfor the internal + 5V regulator. R A Mwobble problems should be familiar toall readers and Memotech is no excep-tion but the company provides a Velcrostrip which binds the packs to the ZX-81 and other packs. T he instructionsare clear and concise in a booklet accom-panying each pack but they are expens-ive,

The Sinc lair I 6 K R A M pack hasreceived both complaints and praise.The complaints are f r om users w hohave had to experience RAM pack wob-ble, which occurs when using the Sin-

u pP ro ni nclair keyboard. The design o f the RAMpack is such that i t is not connectedfirmly to the ZX-8I and the top of theRAM pack rests against the top o f theZX-8I case. Every time the keyboard isused that lifts the RAM pack from thetable and shakes it. The edge connectoreventually becomes so loose that anyslight movement will disconnect it fromthe ZX-8I, corrupting the ZX-81 mem-ory.

Several methods have been producedto stop the wobble — flexible cables sothat the RAM pack can be laid flat onthe table f r om dK'tronic s and t h eRAM-LOK f r o m Adapt Electronicswhich bolts together the Z X- 8 I andRAM.

The best method, though, is to buy aRAM pack which has been designed toeliminate t h e wobble. T h e y consistmostly of not allowing the circuit boardto be connected t o the casing o f theRAM pack, so that the board can moveup and down inside the case with themovement of the ZX-81. A reliable stiffedge connector is also required. Some,like that from Cheetah, have also beendesigned to wrap round the back of theZX-8I so that there is litt le movementbetween the two casings. Some manu-facturers a r e a ls o us ing +5V- on lyRAMs so that they d o not have t oprovide a power supply from the +9 Vsupply which can vary depending onthe equipment used.

Kayde, Camel and Econotech I 6 KRAMs are good examples o f the fi rsttype, the first two being cased. The ZX-Panda and the Cheetah are good exam-ples of the second type,

The ZX-Panda can also be used togive 32K by adding a small PCB con-taining I6K more RAM inside the case,The Audio Computers RAM pack pro-vides a fair ly stable I 6 K R A M pack‘vhich has a hook to hold it on to the


back of the ZX81 and can be fitted withan XROM pack which makes i t evenmore useful as i t provides EPROMloading and saving facilities. Some o fthe RAM packs provide a LED — alittle red light — but that only providesan indication that there is power to theRAM pack and not whether it is work-ing correctly.

The best choice is obviously a non-wobble RAM pack which is inexpen-sive. I f you can afford i t and do notwant to use pre-programmed ROMs orother devices, opt fo r a cheap 64KRAM pack. They take up just as muchpower as the 16K and wil l also workwith the Sinclair printer — see the tablefor a list of facilities of the various RAMpacks.

Basicare provides a different kind o fRAM; you must first buy a base moduleto use its RAM, called a Persona. It is in16K and 64K packs for the ZX-8I up toa maximum o f 5I2K. That is dividedinto banks and you wi l l require othermodules to have the banks talk to eachother. The maximum memory availableat one time is 32K. It is the only systemwhich allows you to run big programsbut at the moment there is very littlesoftware to run it.

Yet another type o f RAM pack isavailable and that is the battery-backedRAM — DROM, which allows the userto do things which normally would haveto be run i n from tape — instantly.They can provide storage for routines toside-scroll the screen in any direction,assemblers, new operating systems toreplace the Sinclair ROM or even yourown favourite Basic program.

A multitude of DRUM packs is pro-duced by Camel Products. Two of themwork on the ZX-8I, the Memic 81 andthe Cramic. The Memic 81 containsone or two static 2K by one-byte chipsgiving 2K or 4K of RAM backed-up by

RAM pack Anti-wobble + 5%' only Cased Price

Basicare I6K i.- ,---- £26.75

Basicare 84K p•--- ..,- (76.25

Camel I 6K .-- ,-, .--, £20.14

Camel 64K .-- •..-

£80.45

Cheetah I6K •-- ,.•• (19.75

Cheetah 64K ..- ...- 144.75

Econotech I 6K ••,-• £20.95

diCtronies I 6K •-* ,..- £22.95

dK'tronics 84K .-- ,,--- /52.15

Audio Computers ,--- 0-

.•- £11.85

Memotech I 6K .., L29.116

Mcmotech 32K ., L19.95

Memotech 64K •-, ,-,i'

09.00 _Sinclair 1611. vo i211.95

VC-Panda ., ..• ot ‘19.95_____J


a battery when the power i s o f f topreserve its memory. That occupies anyposition in 8K-I6K area of the memorymap. DROM devices allow you to writea machine code or a Basic program andtransfer i t into the 8K-16K area o f thememory map. Machine code can be runfrom there, saving valuable RAM space,but Basic programs must be uploaded tothe Basic area before running the pro-gram.

That means that any Basic programis limited to 8K unless the Cramic isused which is 16K long. The routinesfor the transfers are included i n thenotes with every pack and consist o fmachine code routines which must berun by using the USR command.

The Cramic is a special case as the16K can be switched in or out by asoftware switch and so a Basic programcan be loaded from tape into the Cramicand sealed-off from the ZX-81. Power-ing-off the ZX-81 then has no effect, asthe RAM module has its own battery tokeep it operating. The program can berestored by powering-up the ZX-81 andrunning a machine code program tostep back i n the Cramic where youceased. That leads to my first criticismof the notes; nowhere is i t mentionedthat you should save the machine codeprogram on tape, i n case somethinggoes wrong.

The code required is very short but asit needs to be put into memory beforeusing Cramic it would have been better

to load it front tape. I hat routine couldhe stored in the Memic 81, o f course,which is outside the Basic area and theroutine loaded into the Basic area fromthere. The advantage o f DROM overROM is that i t can be changed.

The other DROM is available only inkit from from Hunter Electronics andconsists o f board which plugs into theback of the ZX-81 and provides 2K o fbattery-backed R AM, wi th space fo rthree more chips. I f you wish, some ofthem can be turned into ROM socketsto take 2K or 4K EPROMs.

The RAM pack race has now becomeso cut-throat that a few firms whichwere doubtful have withdrawn. Th efirms remaining are giving the custom-ers what they want, depending on price.Cheap i s no t necessarily nasty anymore. So look for the bargains — theyare there to be found.DRomsmemic at 4K ( 3 4 . 4 5Cramic I6K L 9 I • 9 5Basica re 2K £ 3 9 . 5 0Hunter 2K L 1 9 . 9 5SUPPLIERSBasicare Microsystems Lt d, 1 2 Pi ckettStreet, London 5W6Cambridge Microelectronics (Camel). 1 Mi l -ton Road, CambridgeCheetah Marketing Ltd. 3 5 9 The Strand,London WC 2JRS lEconotechl. 1 9 Wayside Avenue, %Northing. Sussex.diCtronics, Uni t 2 , Shire Hill I nd. Estate,Saffron Walden, Essex.Audio Computers (Solidisk Ltd). 87 Bourne-mouth Park Road, Southend-on-Sea, Essex.

133

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Send cheque !PO now to:CHEETAH MARKETING LTDDept SA24 Ray StreetLondon EC1 R3 DJTel: 01 2 7 8 6 9 5 4

32K RAM Pack and "SWEET TALKER" also available f rom larger Branches o f

Pr John Menzies WH SMITH


Sinclair has been overtaken by other suppliersof upgrades. Stephen Adams reports.

Spectrumfinds itselfat full stretchT.

/IE SPECTRU M is in four ha-sic forms. Model Is which havetwo IC-type sockets into which

a printed circuit board is plugged andmodel 2s which have all the RAM fittedon to the main pr inted c ircuit board.There are, of course, two types in eachcategory, the 48K and the I6K.

The 48K cannot he expanded, as allthe existing memory space is coveredwith either ROM or RAM — all 64K ofit. The ROM can be switched-out exter-nally to add different ROMs using theROMCS but the RAM cannot as thereis no equivalen: RAMCS.

Therefore all memory expansions canbe done only to the I 6K models. As thecomputer already contains I 6 K o fRAM, the top 32K o f memory area —32K-64K — is the only space to put it.Most memory expansions t ill that spacewith 32K worth of RAM chips but theEast London Robotics 64K add-on —the SP80 — has two sets of 32K RAMwhich can be switched in and out undera program instruction or from the key-board.

The k its consist o f four memory-decoding chips, except model I versionswhere all the chips are soldered to aPCB, and eight 32K by one-bit chips.Those RAM chips are very sensitive tostatic electricity and warnings are in-cluded in all the instruction sheets. Theway to handle them properly is not toremove them f r o m the ir protectivepackaging un t i l needed and t o keeptouching an earthed object such as aradiator or gas pipe occasionally to re-lease the static charge. The static can becaused by nylon or wool in your cloth-ing being rubbed.

Putting-in the chips can be a lit t ledifficult and it is recommended that youcheck that the pins are straight beforeyou insert them. The Fox Electronicskit has the pins already straightened.

Also check that none of the pins is bentoutside the socket o r underneath thechip when you have finished.

The best technique to use is to put allthe pins on one side into the socket andthen to pull the pins on the other sideover the holes in the other side o f thesocket. Once both sets of pins are rest-ing in the socket holes You can pushdown gentlr on the chip to push it intoits socket.

The instructions vary from a four-page. step-by-step meticulous descrip-tion by Delta Research to one page justlisting where the chips go by Fuller .Apart f r om the Fuller instructions allprovided sufficient detail to allow youto know where each chip goes and whatprecautions to take.

As part o f its instructions Fox Elec-tronics also includes a sheet showinghow to tune the colour on a Spectrum togive better results. I t also shows youhow to tell whether it is the Spectrumor the TV set causing a problem. Sheets

'The 48Kcannot beexpanded'

normally cost L I f r om Fountain Elec-tronics but are free with its R AM k it,along w ith a small Basic program t odemonstrate the usefulness of 48K.

The l in ing o f the Fox k it was theeasiest but i f you have problems you cansend back the k it with the details of theSpectrum at any time in the following12 months. East London Robotics w illfit the chips at an extra cost o f f.7 bypost or £3 by personal visit.

Delta sends a memory test tape whichchecks all the memory by using a ma-chine code program going through at

least a l l the manufacturer's specifica-tions. The tape can be used to keep aneve on suspect memory faults as it stopswith an error which can then be sentback t o Delta o r Sinc lair . T h e tapenormally would cost 113_50 and is awally comprehensive test taking at leasteight minutes.

Fast I .ondon Robotics and D e l iawere the only model I boards we couldtest and both could be fi tted easily withless trouble than the model 2.

East London Robotics also does anSP80 k it whic h can prov ide 64K o fmemory in the same sockets as the 5P48(18K) fitted_ That is achieved by hayingtwo separate banks of 32F, switched byan O UT instruction_

That is possible only because o f the64K RAM chips which are used insteadof the 32K RAMs and a massive modifi-cation of the decoding chips which pluginto the Spectrum. N o soldering is re-quired but some care needs to be takeninserting the chips, as three of them arewired together using twisted insulatedviire.

A LED is also soldered on to one ofthe chips t o indicate whic h bank isbeing used. T he only problem is thatyou can sc.,: it only with the top of f orlooking thr ough t h e edge-connectorhole. The LED lights when it is in banktwo and when the machine is turned onthe light shows on bank one.

The only problem with the SP80 isthat the stack and any program runningin i t must be in the I 6 K o f memoryprovided by Sinclair. I f it was allowedto go in to the top 32K i t would beswitched-out on the first O UT instruc-tion and the program would have no-where to go.

Also the machine code stack for re-turn addresses would have to be in thelower 16K area for the same reason.That leaves the user to develop a pro-

SINCLAIR USER Annual 1984 I 35

gram which will be able to use banks ofmemory without having th e conve-nience of Sinclair Basic to cope with it.

Prices of the various kits are detailed,along with an indication o f how goodthe instructions were, guarantee periodand number of tests performed on mem-ory after fitting.

It is also possible to add a RAM packon the back o f the Spectrum. A Spec-trum-type 32K R AM pack has beenproduced by Cheetah Marketing Ltd. Itfits very snugly on the back o f theSpectrum and because i t is outside thecase it does not matter i f it is model I ormodel 2.

It also has an extension piece on theback so that you can plug in Micro-drives when they arrive. The R A Mpack has no known wobble in use andcan be fitted very easily by plugging i tinto the expansion port. It costs £39.95.

The alternative is to use a ZX-81-type RAM pack with an adaptor to giveyou another I6K or 32K. To use it youwill require an adaptor.

EPROM Services and myself bothmake adaptors for the 16K RAM pack.Mine can also cope with a 64K RAMpack to give a full 32K by changing asoldered strap on the board or orderinga 64K version. I also produce an AdamII which lets you have a 16K R A M

• • • •

136

pack on the back o f the Spectrum butwhich also allows devices which used towork in the popular 8K-16K region towork in the 56-64K region of the Spec-trum. Al l the adaptors rti•mtioned costLSI•

Of the RAM packs and kits reviewed.Fox Electronics for kits and Cheetah forRAM packs stand out as good value formoney.

Fox Electronics, 141 Abbey Road, Basingstoke. Hampshire. Tel: 0256-20671

Cheetah Marketing, 3 5 9 The Strand. London WC2 OHS. Tel: 01-240-7939,

East London Robotics. No. 11 Gate. RoyalAlbert Docks. London E16. Te l- 0 1 - 4 7 13308

Delta Research — cheques to Servodata Ltd— 1 5 Church Street. Basingstoke. Hamp-shire. Tel: 0635-45373.

Fuller Micro Systems. 71 Dale Street, Liverpool 2.

Producer R A M I ns t r uc t i ons M o d e lFox 3 2 K G o o d 2ELR 3 2 K G o o d 2Delta 3 2 K V . good IDelta 3 2 K 1 i r . good 2Fuller 3 2 K P o o r 2ELR 3 2 K . Average 2ELK 6 4 K A v e r a g e IE' 6 4 K A v e r a g e 2

yo 114-1

oad' 'MI ell

..•••••••

Eprom Services. 3 Wedgewood Drive, LeedsLS8 1EF. Tel: 0532 667183.

Stephen Adams, 1 l eswi n Road, LondonN16 7NL.

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A world of activity for youand your Sinclair

Whether you have a M O , 2.X81 or Spectrum — we can show youthere's far more to your Sinclair than you ever thought possible.

That's the active, lively wor ld of Sinc lair User — the first magazinewritten specially for everyone who owns or uses a Sinclair

computer.Every month, there is a whole range of games, business ideas and

bright new ways to learn. There is the Sinclair User Club, withspecial exclusive member offers. There are technical facts,

development news and advice, plus hints from other users andanswers to queries — in fact everything you need to be an

interested, informed and ACTIVE Sinclair user.There's just one problem — Sinc lair User sells out fast! So make

sure you don't miss your copy: order it today from yournewsagent — or complete the subscription

form below and we willsend it to you direct, every month. • • • •• • , ,e t o

I p s elw, v ,

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s o ° v et s o ty •

01•41.

Date -


1

Thoughtful PresentsBuy the latest in educational toys for Christmas— educational software. LCL has learninggames and useful courses, for the Spectrum,ZX-81. BBC. VIC, Electron, Apple and PET, forexample.MICRO MATHS. 24 program self-tuition or revisioncourse to 0-Level. £24.50 (except ZX-81 i14.50).

ANIMATED ARITHMETIC. Teaches using movingcolour pictures (not words), includes ClownCount and Addition Express £6.50.

, The programming standard is high. Theprograms are robust

TIMES EDUCATIONAL SUPPLEMENT

RETURN-OF-POST service for Micro Maths. Phoneor send orders or requests for free catalogue to:

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NEW FOOTBAL

• r • .4,- / • ! • • • 0 3D ot the gorne to tOalball and ten, •i,

one side the computer plays the other The campule r IS talit and hardto •i•• :Af f e re n t skill levelsFOOTBALL'Each player can move. shoot etc. Independently Includes touts it players=O d e . corners. thraw-inS e tc Sca le 90 minutes ploy Arty team of names ca nbe used Ga m e ca n be suspended a nd Player numbed, Shown a t the press ota key Price 15•50,INC MATCH SOCCERJust hhe football ga me but for 2 playerS Ea ch player use's keys at his sKie of thekeyboard to Control his men. MI men ca n be moved. snoot etc rndePersder'lPractice volt tootba ll then Pla y your Mends vs the big ma tch Price E5-5 0SUPER SOCCE*A de luxe VerSiOrl of the football Eve n roster a ction. ha rde r to be a t Chorus,team colours etc Price £7.00.timidEach ke y pla ys a aittfment sttoke M o ve your pla ye rs a nywhe re o n courtComputer pla ys a ha rd ga me All tennis rules used, just like the re a l thingProper serving and scoring. Plays 3 sets Animated hgutes PRICE 15•50-1AFK !SAME30 view from the 11311iCS turret ot woodS, villages. artacsung tanks etc Shots cry.destroy buisongs. trees a nd enemy tanks. 360 degree turret movement Price14.50_CAR RACEYou a w e one car, the computer the Other Control your ca r with steering a ndri•oikes C hoice of 2 circuits L a p counters a nd time re corde d N ice i3 •9 5 .

Buy any 3 games, gel any game freer k , n r r x-, 3 ! 1 ,0 ( N I CA V S. 7 nor

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l i b,• •• •• •

Put everythingyou need onthe keyboardwith a CustomKeypanel Kit.

1 .3 1

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s t

Even ihing you need!Son the keyboard with

CLIS.11 KEYPAN ELS.

These precision die-cut plastic panels fit perfectlym'er your keyboard and provide an instant andindividual reference to all of your software.

Each Kit comes in a clear plastic storage wallet and(1 Mt AIM: ID Matt-black Keyr)anels plus sheets

)iitaining over 140 self adhesive Command labelspre-printed with words, symb( )Is and arrows, plus asheet of blanks fi )r your Own designs.

SPECTRI 'M KEYPANELS arc 96x 22-i m m a n d t h e

labels are printed in ' Spe c-i t-U M' b r i g h t r e d . A M I :N I '

for flight-simulation and all multi-key games andapplications.

The H IM' add-on for your Spectrum.ORIC KEYPANELS are I OS x 275 m m a n d t h e l a b e l s

are ' O M ' blue, Master those CTRL and ESC keycombinations.

An INSTANT reference to all ORIC's keyboardfunctions.

NOW IN 'SI PER MI: MASTIC!

FPI )st today to Softeach Limited, 25 College Ri lad. Reading..

I rkshi re. RG6 I QE, ut• (14-4mch t, !•1 le first (-Li s s p • • • 1 M U M

PICANC send me:S p e c t r u m KeypanelKits21+ 3 ipp8 Lpeach(overseas should add 251/4 for additional surface mail )( ) R I C Ktwa ne lKitsat£4.95+ 3 5 pp & p each( owrscaN should add 25% for additional surface mail

I enclose a total remit tanCe c h e q u e s / 1 1 ° m Aorders payable tit Softeach Limited.NAMEADDRESS

1 37

min ro •-• 116_ 11_11MD N E n on a a MAI momill W i m . m m "

a C O M P U T I N G° 1 1HIGH-RES ZX81 PROGRAMS

AGE HardwareBeilliowerBridge Softwa reBug-byteCCSCatpec Computer Softwar.,

I 2684

121• de94

Carnet' Softwa re Ltd 5Cascade Games . . . . . 19Cheetah M a rke ting.. • 34ComputerlockCrystal Computing 44Dean Electronics. . . . . . . . . 18Doric Computer Se rvice s /8East London Robotics 31Fantasy Softwa re 139Fox Ele ctronics I 30Fuller M icro Syste ms.... 98Gr iffi n & Ge or ge 9Hartland Softwa re 113Hestacrest Ltd 113Hornby Softwa re I 201SP . . . . . . . . . . . . . . 82ides Ele ctronics.. '1 3Kelwood Computer Cases 6Kemp Ltd ' 20Kernow Softwa re Se rvice s 113Kosrnos Softwa re 72LCL 137Load Runner ' IsMegadodo So f t w a re • 20Micro 1 Lid , 38Micro M aster 36MicrosphereMikro Gen. 91MyrrnitiOn Softwa re 84M cAlley, BS 72National E.te osion College 44Next Computer Syst e m s 38Odyssey Computing 138Pan Books 84Richard Shepherd Softwa ri• 813 87Rose Softwa re 44Silyersoft Ltd 1

09

Softeach Ltd 137Stellar Softwa re 121Sussex Ta pe s.. 127Terminal Sof twa, ,

21Transform Ltd 138Treetop Designs . 121Ultimate Pla y the Getne • 17Visions 'Softwa re Fa ctoryi 71Widgit Softwa re '20William Stuart Syste ms 127Winters Ltd . . . . . '377

We uti l is e • S OFTWARE ONLY ts c h n i q u • to pr oduc e s H IGH RE S OLUTION DIS P LAYon the U N M OD IFIE D 161( V I S I N O H A R D WA R E A D D ON S ARE R E QU IR E D fo rthe fo l l o w i n g p r o g r a m s .INV ADE RS — r e v i • w a d • c • te l i c • I l y in • ZX C om puting • t h e H i - r e e display( 495 does break new ground—en excellent gam... an oist•tending

•c h i • v e r n e n t. . A e we l l as the M il- res dis pla y th e fa c i l i l le a °H otr od• r • om pr e • s iv e l.. . A c tion is s m ooth • n d f • s t too , a n d the im plos ionw h • n h i t r os ily Is s h a tte r i n g I-- N e e d w e s a y m o r • I I

GRAP HICS — e na ble s y ou t a u s . high r • s olution gr a phic s in y our o w n pr ogr • r n•1'6 S6 T h e c or tion• nd• a r e C I S . P R IN T. P LOT. P OK E . D R A W . S P RITE a n d

s c a t a INOIFF C o m p r • h e n a r v i s • d i t i n g f • c i l i t i • • a r e pr ov ide d u n i tShe G r a p h i c s c o m m a n d s a r e e a s ily Inc or por a te d into BAS IC programs

201II1 — a n • dv a nc or d a r c a de g• r ne inc or por a ting l i v e d i ffe r e n t s h e e t , —1 5 9 9 I N V A D E R S , i M u u tl A p a s , ZOR FIA N S . M E TE OR S TOR M A MOTHERS/11P

imP rogrem• l d i f fi c u l t y a n d s ix g e n e O p ti o n sS WARM — a l e s t m o v i n g • r c is ti• ty p e g e m * . S h o o t d o w n the s a uc e r s a sE 2 SS t h e y d a r t m i c r o " th e • c r • • r t fi r ing the i r m is i ti le e d i f fi c t i l l Y

N E W L O W P R I C E ICAVE C R U S A D E — th i s is • f a l l m ov ing g e m s i n w h i c h th e p la y e r m u s t e s c a per 2 SS f r o n t a come pur s ue d by i ts fe r oc ious i n h • b i te n ts . T h i s g a m e d o e s

not us e high r e s o lution g r a p h i s • b u t th e nor r n• I g r a ph ic s a r e ti l te dto g o o d • ffs i c t. N E W L O W P R I C E

FOR THE 48K SPECTRUMS P E CTRAL Z O R F — s im ila r i n uur .2) ( 81 p i n g i • M b u t u s i n g c olour e nd S oundf A 95 T I N . le l i v e ga m e s i n one e a th e pla y e r c a n c hoos e to play

one • I te e t c o n ti n u o u s l y i f s o distir r • d. N E W L O W P R I C ECI4110 5 P L A Y — d e s i g n e d a s a te a c h ing a id fo r pr e - s c hool c h i ld r e n w i t h i h eEA 116 p a r t i c i p a t i o n o f a pa r e nt or tir e c h• r E s c e l l e n t us e r ne d• o f th e

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SPECIAL OFFERBuy t w o o r m o r e p r o g r a m s fo r a d is c ount o f C l pe ir p r o g r a m I I I

We a r e c o n e te n tl y l o o k i n g fo r gus ti l y S p e c tr u m s o f twe r a fo r wh ic h w e pa yupto 23'S r oy a ltie s I f y ou h a v e w r i t t e n s uc h • pr ogr • ns th e n • e n d • " m o l eto us fo r a n i m m e d i a te • ve ll.i• E iOn W e e q . a ltr is in te r e s te d in p r o g r a m sw r i t t• n u s i n g o u r G R A P H I C S pr ogr • r r o f o r t h e 2Tr a de e nqui r e s s ir • w e l c o m e

ODYSSEY c o r e p tr r i n G . 2 8 B IN GH A M ROAD. S H E R w o o n . NOT ti N i G H A M RE DS 2E1P

138

M Z 8CMOS STORAGE/MEMORY

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't14*lbir'r Lit• Centronics Interface• U s e your Spec t r um w i t h a full-s ize pr inter

• • Microdrive compatible.* Double size graphics screen copy

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• * Produces colour screen dump withthe Tandy CDP 115 printer.

* Supports a wide range of softwareincluding Tasword, Masterfile,

• O m n i c a l c , Invoicing etc.

* Uses the Spectrum graphic charactersto control printer codes.

• * Enables you to connect 2 Spectrums

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