A Brief Tour of The History of Computers Presented by Kevin Nichols KA7OFR.

A Brief TourA Brief Tourofof

The History of The History of ComputersComputers

Presented byPresented by

Kevin NicholsKevin NicholsKA7OFRKA7OFR

The History of ComputersThe History of Computers

►About meAbout me►What I’ll be talking aboutWhat I’ll be talking about

Primarily information on selected Primarily information on selected computers from the 1930s - 1950scomputers from the 1930s - 1950s

A few details of how specific computers A few details of how specific computers workedworked

Such a vast field, I can do no more than Such a vast field, I can do no more than touch briefly on what’s out theretouch briefly on what’s out there

PreliminariesPreliminaries

►What What isis a computer? a computer? A computer is “a machine that manipulates data A computer is “a machine that manipulates data

according to a list of instructions” according to a list of instructions” – Wikipedia– Wikipedia

A programA program historically distinguished historically distinguished computerscomputers from from calculators, calculators, but not alwaysbut not always

Distinction is also made between devices that Distinction is also made between devices that have conditional instructions and those that do have conditional instructions and those that do notnot

Early computers came in two flavors: Analog & Early computers came in two flavors: Analog & Digital, And three methods of implementation: Digital, And three methods of implementation: Mechanical, Electric & ElectronicMechanical, Electric & Electronic

Early Calculating DevicesEarly Calculating Devices

►Many examples of early Many examples of early calculatingcalculating devicesdevices Abacus / SorobanAbacus / Soroban AstrolabeAstrolabe Napier’s BonesNapier’s Bones Slide RulesSlide Rules

Early Calculating DevicesEarly Calculating Devices

►But none of these are computers if we But none of these are computers if we adopt the definition that a computer is adopt the definition that a computer is a device that contains a a device that contains a programprogram, a list , a list of instructions to carry out of instructions to carry out automaticallyautomatically

►What I will discuss today are early What I will discuss today are early mechanical and electronic computers mechanical and electronic computers that have the ability to be that have the ability to be programmedprogrammed

““Computer”Computer”

► Side Note: The term “computer”, a term in use Side Note: The term “computer”, a term in use from the mid 17from the mid 17thth century, meant a person who century, meant a person who performed mathematical calculations (“computors”)performed mathematical calculations (“computors”)

First ComputerFirst Computer

►Which was the “first” computer?Which was the “first” computer? Highly controversialHighly controversial Depends on specific terms and precise Depends on specific terms and precise

qualificationsqualifications►““First electronic computer with stored program First electronic computer with stored program

memory” vs “First stored program computer” vs “First memory” vs “First stored program computer” vs “First electronic computer”electronic computer”

Not my intent to try to pin it down hereNot my intent to try to pin it down here I’ll just present several of the more “interesting” I’ll just present several of the more “interesting”

and historical computers, and leave it to you to and historical computers, and leave it to you to research which you think was the “first” research which you think was the “first”

Computer CategoriesComputer Categories

► Categorizing computersCategorizing computers Initially computers were human, then Initially computers were human, then

mechanical, then electric, and finally electronicmechanical, then electric, and finally electronic Differentiated by the calculating “medium” usedDifferentiated by the calculating “medium” used

►MechanicalMechanical Gears, shafts, pulleysGears, shafts, pulleys

►Electrically operatedElectrically operated RelaysRelays

►ElectronicElectronic Vacuum tubes, Transistors, ICsVacuum tubes, Transistors, ICs

Differentiated by the method of computingDifferentiated by the method of computing►Analog was initially faster, but less accurateAnalog was initially faster, but less accurate►Digital was initially slower but more preciseDigital was initially slower but more precise

Computer CategoriesComputer Categories

MechanicaMechanicall

ElectricalElectrical Electronic Electronic (tube)(tube)

Electronic Electronic (transistor/IC)(transistor/IC)

AnalogAnalog

DigitalDigital

•Vannevar Vannevar Bush’s Bush’s Differential Differential AnalyzerAnalyzer

•Instructional Instructional computers (GE computers (GE EF-140)EF-140)

•Babbage’s Babbage’s Difference & Difference & Analytical Analytical EnginesEngines•Zuse Z1Zuse Z1

•Bell Labs Bell Labs Relay Relay Computers Computers (Complex (Complex Number Number Calculator)Calculator)•Zuse Z3Zuse Z3

•Op-Amp Based Op-Amp Based Computers Computers (Heathkit ES (Heathkit ES Serias)Serias)

•EniacEniac•EdvacEdvac•Manchester Manchester “Baby”“Baby”•EdsacEdsac

•Op-Amp based Op-Amp based “plugboard” “plugboard” computerscomputers

•Modern Modern ComputersComputers

Digital / Mechanical Digital / Mechanical ComputersComputers

1800’s & 1930’s1800’s & 1930’s

Digital / MechanicalDigital / Mechanical

Babbage Difference & Analytical Babbage Difference & Analytical EnginesEngines

► Charles Babbage, 1791 - Charles Babbage, 1791 - 18711871

►Work included design of two Work included design of two classes of machinesclasses of machines Difference EnginesDifference Engines

►Used method of finite differencesUsed method of finite differences►Uses only addition & subtractionUses only addition & subtraction

Analytical EnginesAnalytical Engines►Mechanized true “computer”Mechanized true “computer”►Would have allowed decisions to Would have allowed decisions to

be made based on previous resultsbe made based on previous results Decimal based machinesDecimal based machines None of his machines were None of his machines were

ever completed in his lifetimeever completed in his lifetime

Image courtesy Computer History museum, Mountain View CA



► In 1800’s, In 1800’s, mathematical tables mathematical tables were used extensively were used extensively for Astronomy, for Astronomy, Engineering, Finance, Engineering, Finance, insuranceinsurance

► Tables were generated Tables were generated by hand and prone to by hand and prone to errorserrors

► These are what These are what prompted Babbage to prompted Babbage to work on his work on his mechanical devices mechanical devices Image courtesy Computer History museum, Mountain View CA



►Babbage utilized the method of “finite Babbage utilized the method of “finite differences” to create the differences” to create the mathematical tablesmathematical tables

►Eliminated the need for more Eliminated the need for more complicated operations (multiplication, complicated operations (multiplication, division)division)

►Easier to implement using mechanical Easier to implement using mechanical devicesdevices



► Say we want to calculate Say we want to calculate the function F(x) = X^2 + 4the function F(x) = X^2 + 4

► The first several values of The first several values of the function are calculated the function are calculated (by hand)(by hand)

► Columns of differences are Columns of differences are calculated until they are calculated until they are constantconstant

► The rest of the values of the The rest of the values of the function can then be function can then be calculated (without calculated (without multiplication!)multiplication!)

► Any nAny nthth degree polynomial degree polynomial can be calculated starting can be calculated starting with the nwith the nthth difference difference

► That is what Babbage was That is what Babbage was trying to “mechanize”trying to “mechanize”




► Difference Engine #1, Difference Engine #1, 18211821 25,000 parts25,000 parts Est. 15 tonsEst. 15 tons 8 ft high8 ft high Designed to calculate Designed to calculate

polynomial tables using polynomial tables using method of finite differencesmethod of finite differences

Work was halted in 1832 Work was halted in 1832 due to dispute with a co-due to dispute with a co-workerworker

Portion of Difference Engine #1, 1832Image courtesy Computer History museum, Mountain View CA



► Difference Engine #2, Difference Engine #2, 1847 - 18491847 - 1849 8,000 parts (3x less than 8,000 parts (3x less than

#1)#1) 5 tons5 tons 7ft high, 11 ft long, 18” 7ft high, 11 ft long, 18”

deepdeep► Could compute 31 digit Could compute 31 digit

resultsresults► Up to 7Up to 7thth order order

polynomial (could hold 7 polynomial (could hold 7 differences)differences)

► Included a paper printing Included a paper printing press with mold for typepress with mold for type

Working reproduction of Difference Engine #2Built from 1985 - 2002, using Babbage’s original designs


Video…



Video courtesy: Computer History Museum, Mountain View CA



► Babbage also designed Babbage also designed a much more ambitious a much more ambitious calculating device: The calculating device: The Analytical EngineAnalytical Engine

► Contained a memory Contained a memory (the “store”) and an (the “store”) and an arithmetical unit (the arithmetical unit (the “mill”)“mill”)

► Could add, subtract, Could add, subtract, multiply & dividemultiply & divide

► Was programmable Was programmable using punched cardsusing punched cards

► Capable of conditional Capable of conditional branches and loopsbranches and loops Portion of the “mill” of the Analytical Engine, 1871

Image courtesy Science Museum, London England


Zuse Z1Zuse Z1► Konrad Zuse, Germany, Konrad Zuse, Germany,

1910 - 19951910 - 1995► Z1 built 1936 – 1938 in Z1 built 1936 – 1938 in

apartment of his parentsapartment of his parents► Binary computer using Binary computer using

metal plates as logic metal plates as logic elementselements

► Programmed via punched Programmed via punched tapetape

► 2 registers of 22 bits each2 registers of 22 bits each► Floating point numbers(!)Floating point numbers(!)► Clock frequency of 1 HzClock frequency of 1 Hz► Destroyed in Dec. 1943 Destroyed in Dec. 1943

during WW II Berlin during WW II Berlin bombardment bombardment

Reconstructed Z1, 1986 - 1989


Zuse Z1Zuse Z1

►Metal sheets Metal sheets function as logic function as logic gatesgates ANDAND OROR NOTNOT

NOT

OR

Part of original metal plates, Z1


Zuse Z1Zuse Z1

ClockOutput

Input


Zuse Z1Zuse Z1

ClockOutput

Input


Zuse Z1Zuse Z1

ClockOutput

Input


Zuse Z1Zuse Z1

ClockOutput

Input


Zuse Z1Zuse Z1

ClockOutput

Input


Zuse Z1Zuse Z1

ClockOutput

Input

Analog / Mechanical Analog / Mechanical ComputersComputers

Early 1900sEarly 1900s

Analog / MechanicalAnalog / Mechanical

Bush Differential AnalyzerBush Differential Analyzer► Vannevar Bush, 1890 – 1974Vannevar Bush, 1890 – 1974► Engineering professor at MITEngineering professor at MIT► Built the Differential Analyzer, Built the Differential Analyzer,

1928 – 1931 to solve electric 1928 – 1931 to solve electric power transmission problemspower transmission problems

► Used metal rods, gears, wheelsUsed metal rods, gears, wheels► Designed to solve up to 6Designed to solve up to 6thth order order

differential equations & calculate differential equations & calculate up to 18 independent variablesup to 18 independent variables

► Solves differential equations by Solves differential equations by integration, 2% accuracyintegration, 2% accuracy

► 150 motors150 motors


Bush Differential AnalyzerBush Differential Analyzer

►The Differential Analyzer consists of The Differential Analyzer consists of several interconnected partsseveral interconnected parts Disk & Plate IntegratorsDisk & Plate Integrators Torque AmplifiersTorque Amplifiers Input/Output tablesInput/Output tables All the connecting gearing, rods, etc.All the connecting gearing, rods, etc.

►Great effort required to set up the Great effort required to set up the computer for different problemscomputer for different problems




Bush Differential AnalyzerBush Differential Analyzer► Integration performed Integration performed

with glass disk with glass disk integratorsintegrators

► Uses knife edge wheel Uses knife edge wheel rolling on glass diskrolling on glass disk

► Rotation of output Rotation of output shaft depends on shaft depends on rotation of input glass rotation of input glass disk, and distance of disk, and distance of wheel from center of wheel from center of diskdisk


Bush Differential AnalyzerBush Differential Analyzer► Torq AmplifierTorq Amplifier

Required due to the Required due to the very low torque output very low torque output available from the available from the integrator wheelintegrator wheel

Wheel must not be Wheel must not be allowed to slip on glass allowed to slip on glass diskdisk

►Output rotates at Output rotates at same velocity as same velocity as input, but with greatly input, but with greatly increased torqueincreased torque



► Input/Output TablesInput/Output Tables Input tableInput table

►Provide arbitrary input Provide arbitrary input as computer runsas computer runs

►Computer drives ‘X’ Computer drives ‘X’ direction, human turns direction, human turns knob to make pen knob to make pen follow curvefollow curve

Output tableOutput table►Computer drives pen Computer drives pen

in ‘X’ and ‘Y’ in ‘X’ and ‘Y’ coordinates to draw coordinates to draw curve on papercurve on paper



► Examples of useExamples of use Calculation of firing tables for artillery used in WWIICalculation of firing tables for artillery used in WWII ““Bouncing Bomb” by Barnes Wallis for attack on Bouncing Bomb” by Barnes Wallis for attack on

Ruhr Valley Hydro dams in WWIIRuhr Valley Hydro dams in WWII►Height, length, number of bounces calculated based on Height, length, number of bounces calculated based on

changing parameters of:changing parameters of: Bomb initial spin, Speed & height of aircraft, Weight of bombBomb initial spin, Speed & height of aircraft, Weight of bomb Bomb shape influencing ballistic characteristics, Buoyancy in Bomb shape influencing ballistic characteristics, Buoyancy in

waterwater

River control studiesRiver control studies►Calculation of soil erosion based in changing parameters Calculation of soil erosion based in changing parameters

ofof Rate at which water falls on surfaces, resistance to flow by Rate at which water falls on surfaces, resistance to flow by

surfacesurface Speed of flow of water, Volume of waterSpeed of flow of water, Volume of water



►A “home made” differential analyzer A “home made” differential analyzer was built in 1934 by Hartree & Porterwas built in 1934 by Hartree & Porter

►Built at the University of ManchesterBuilt at the University of Manchester►Made primarily of Meccano partsMade primarily of Meccano parts

Was actually used for military purposesWas actually used for military purposes Cost 20 poundsCost 20 pounds Said to have Achieved 2% accuracySaid to have Achieved 2% accuracy





►A modern version of the Meccano A modern version of the Meccano Differential Analyzer was recently builtDifferential Analyzer was recently built Designed, assembled and operated by Designed, assembled and operated by

Tim RobinsonTim Robinson Shown at the Vintage Computer Festival Shown at the Vintage Computer Festival

in Californiain California Contains 4 wheel & disk integratorsContains 4 wheel & disk integrators Video…Video…

Digital / Electric Digital / Electric (Relay)(Relay)

Computers Computers

1930s - 1940s1930s - 1940s

Digital / Electric - RelayDigital / Electric - Relay

Bell Relay ComputersBell Relay Computers► Bell Labs / George StibitzBell Labs / George Stibitz

1937 – Demonstrate 1937 – Demonstrate relays used as a binary relays used as a binary adderadder

1939 - Complex Number 1939 - Complex Number Calculator (Model 1 Relay Calculator (Model 1 Relay Computer) DemonstratedComputer) Demonstrated►Cost $20,000Cost $20,000►450 telephone relays450 telephone relays►Calculated quotient of two Calculated quotient of two

8-place complex numbers in 8-place complex numbers in 30 seconds30 seconds

A calculator Not truly a A calculator Not truly a computercomputer

First demonstration of First demonstration of remote accessremote access


Zuse Z3Zuse Z3► Konrad Zuse created Konrad Zuse created

many other relay-based many other relay-based ‘Z’ machines beyond ‘Z’ machines beyond the Z1, Z3 probably the the Z1, Z3 probably the most famousmost famous Operational May 12, 1941Operational May 12, 1941 64 numbers of 22 bits 64 numbers of 22 bits

eacheach Floating point mathFloating point math ““+”, “-”, “*”, “/” and +”, “-”, “*”, “/” and

square rootsquare root 5.3 Hz, Addition 0.8 5.3 Hz, Addition 0.8

seconds, multiplication 3 seconds, multiplication 3 secondsseconds

2600 relays, 4kW, 1 ton2600 relays, 4kW, 1 ton I/O using punched tapeI/O using punched tape No conditional jumpNo conditional jump

Reconstructed Z3, 1960


Zuse Z3Zuse Z3R

eco

nst

ruct

ed Z

3,

19

60


IBM Relay ComputersIBM Relay Computers► IBM / Harvard Mark I IBM / Harvard Mark I

(Automatic Sequence (Automatic Sequence Controlled Calculator)Controlled Calculator)

► Development lead by Development lead by Howard AikenHoward Aiken

► 1944 – Installed at Harvard 1944 – Installed at Harvard UniversityUniversity 51 ft long, weighed 5 tons51 ft long, weighed 5 tons 750,000 parts750,000 parts 72 accumulators, 60 sets of 72 accumulators, 60 sets of

rotary switchesrotary switches► Addition: 1/3 second, Addition: 1/3 second,

multiplication 1 secondmultiplication 1 second


IBM Relay ComputersIBM Relay Computers

Automatic Sequence Controlled CalculatorAutomatic Sequence Controlled Calculator


IBM Relay ComputersIBM Relay Computers► IBMs Selective IBMs Selective

Sequence Electronic Sequence Electronic CalculatorCalculator 1948 – 19521948 – 1952 21,400 relays, 12,500 21,400 relays, 12,500

vacuum tubesvacuum tubes 50 14 digit x 14 digit 50 14 digit x 14 digit

multiplications / secmultiplications / sec Reportedly produced Reportedly produced

the moon position the moon position tables used for plotting tables used for plotting the course of the 1969 the course of the 1969 Apollo moon flightApollo moon flight


IBM Relay ComputersIBM Relay Computers

►Operator consoleOperator console Lots of blinking Lots of blinking

lightslights Machines of this Machines of this

era responsible era responsible for Hollywoods for Hollywoods early fascination early fascination with blinking with blinking lights on lights on computerscomputers

Digital / Electronic Digital / Electronic (Tube)(Tube)

Computers Computers

1940s - 1950s1940s - 1950s

Digital / Electronic (Tube)Digital / Electronic (Tube)

ENIACENIAC► At start of WWII, the Army’s Ballistics At start of WWII, the Army’s Ballistics

Research Lab trained about 100 human Research Lab trained about 100 human computers to calculate ballistics tablescomputers to calculate ballistics tables


ENIACENIAC► The Differential Analyzer & mechanical The Differential Analyzer & mechanical

desktop calculators were used to solve the desktop calculators were used to solve the differential equations of motiondifferential equations of motion

► A skilled operator took about 3 days to A skilled operator took about 3 days to calculate a single trajectorycalculate a single trajectory

► As the war progressed, the BRL couldn’t As the war progressed, the BRL couldn’t keep up and fell way behindkeep up and fell way behind

►No firing table = useless guns!No firing table = useless guns!► This crisis lead to the Army investing in two This crisis lead to the Army investing in two

men with an idea of how to calculate much men with an idea of how to calculate much fasterfaster

Digital / Electronic -TubeDigital / Electronic -Tube

ENIACENIAC► EElectronic lectronic NNumerical umerical IIntegrator ntegrator AAnd nd CComputeromputer► Probably most well known of the early computersProbably most well known of the early computers► Started in April 1943 finished Nov 1945 (after the war!)Started in April 1943 finished Nov 1945 (after the war!)


ENIACENIAC►Developed by John Mauchly and J. Presper EckertDeveloped by John Mauchly and J. Presper Eckert► Built at the Moore School of Electrical Engineering Built at the Moore School of Electrical Engineering

at the University of Pennsylvaniaat the University of Pennsylvania


ENIACENIAC

►The complete computer consisted of The complete computer consisted of several interconnected modulesseveral interconnected modules

► Initiating UnitInitiating Unit► Master ProgrammerMaster Programmer► Cycling unitCycling unit► MultiplierMultiplier► Divider/Square RooterDivider/Square Rooter► 20 accumulators20 accumulators► Input/OutputInput/Output► Constant transmittersConstant transmitters► Function TablesFunction Tables


ENIACENIAC► Eniac used approx. 18,000 radio tubesEniac used approx. 18,000 radio tubes► Experts questioned reliability of tubesExperts questioned reliability of tubes► Eckert’s design for low power, modular Eckert’s design for low power, modular

design worked welldesign worked well


ENIACENIAC► ENIAC StatisticsENIAC Statistics

17,468 tubes17,468 tubes 70,000 resistors, 10,000 capacitors70,000 resistors, 10,000 capacitors 1,500 relays1,500 relays 6,000 manual switches6,000 manual switches 8’ high x 80’ long, weighed 30 tons8’ high x 80’ long, weighed 30 tons Consumed 174,000 watts Consumed 174,000 watts

► PerformancePerformance Could do 5,000 10-digit additions / secCould do 5,000 10-digit additions / sec 333 multiplications / sec333 multiplications / sec Calculate trajectory in 20 seconds (D.A. took 15-Calculate trajectory in 20 seconds (D.A. took 15-

30 minutes)30 minutes)


ENIACENIAC► Computed by counting pulses using base-10 rather than Computed by counting pulses using base-10 rather than

base-2base-2► Eniac’s primary calculating modules were the 20 Eniac’s primary calculating modules were the 20

AccumulatorsAccumulators► Each accumulator consisted of 10 ring counters of 10 digits Each accumulator consisted of 10 ring counters of 10 digits

each each


ENIACENIAC

► Function tables were (laboriously) entered Function tables were (laboriously) entered using rotary switchesusing rotary switches


ENIACENIAC

► Programming consisted of connecting Programming consisted of connecting together the various units with cables together the various units with cables

► ENIAC could not ENIAC could not storestore programs programs electronicallyelectronically

► A program was A program was defined by the defined by the state of patch state of patch cords and switchescords and switches

► ““Reprogramming” Reprogramming” required days of required days of configuring cablesconfiguring cables

Digital / Electronic -TubeDigital / Electronic -Tube

ENIACENIAC

►Eniac was even Eniac was even used as a used as a recruiting toolrecruiting tool

►Army’s 1940’s Army’s 1940’s version of “Be all version of “Be all you can be” ad!you can be” ad!

Video…


ENIACENIAC


EDVACEDVAC

► Mauchly & Eckert proposed & Mauchly & Eckert proposed & started before Eniac was fully started before Eniac was fully completecomplete

► First First designed designed computer for computer for Stored Stored ProgramProgram concept concept

► Built for US Army Ballistics Built for US Army Ballistics Research Lab. Contract signed Research Lab. Contract signed April 1946, completed 1953April 1946, completed 1953

► Contract for $100,000. Final cost Contract for $100,000. Final cost $500,000$500,000

► CapabilityCapability 16 instructions16 instructions 1,024 44-bit 1,024 44-bit binarybinary words words Add (864 us), Subtract, Multiply Add (864 us), Subtract, Multiply

(2.9 ms) Divide(2.9 ms) Divide ““RAM” was ultrasonic delay lineRAM” was ultrasonic delay line 6,000 tubes, 12,000 diodes6,000 tubes, 12,000 diodes 56 kW power56 kW power 8.5 tons8.5 tons

► EElectronic lectronic DDiscrete iscrete VVariable ariable AAutomatic utomatic CComputeromputer


EDVACEDVAC

► Mercury delay lines Mercury delay lines used as “RAM” memoryused as “RAM” memory

► Leveraged research in Leveraged research in RADAR during WWIIRADAR during WWII

► 2 sets of 64 delay lines 2 sets of 64 delay lines of 8 words capacity of 8 words capacity eacheach

► Each tube was 384 us Each tube was 384 us “long”“long”

Representative Univac delay line memory


EDVACEDVAC►One of the first machine to which the “von One of the first machine to which the “von

Neumann Architecture” appliesNeumann Architecture” applies


EDVACEDVAC

► The Manchester “Baby” computer (above) therefore was the first The Manchester “Baby” computer (above) therefore was the first computer to operate with the stored-program concept in June computer to operate with the stored-program concept in June 19481948

► Eckert & Mauchly left the EDVAC project prior to completion, so Eckert & Mauchly left the EDVAC project prior to completion, so it was not the first computer to operate with a stored programit was not the first computer to operate with a stored program


Manchester BabyManchester Baby

► Developed by Tom Developed by Tom Kilburn at the Kilburn at the University of University of ManchesterManchester

► Utilized a “Williams Utilized a “Williams Tube” CRT for memoryTube” CRT for memory

► Stored 2048 bits of Stored 2048 bits of “RAM”“RAM”

► 32 bit word length32 bit word length► 3 bits for instructions3 bits for instructions► Serial binary operationSerial binary operation► Solved finding the Solved finding the

largest factor of 2^18 largest factor of 2^18 in 52 minutesin 52 minutes



► RAM Memory was RAM Memory was Williams Tube stores Williams Tube stores bits as charge on the bits as charge on the face of the 6” CRTface of the 6” CRT



► 7 Instructions 7 Instructions A = -S (010)A = -S (010) A = A – S (101)A = A – S (101) S = A (110)S = A (110) If A < 0, CI = CI + 1 (011)If A < 0, CI = CI + 1 (011) CI = S (000)CI = S (000) CI = CI + S (100)CI = CI + S (100) Halt (111)Halt (111) Later added: A=S, A=A + Later added: A=S, A=A +

S, A = A & SS, A = A & S

Where A is the accumulatorWhere A is the accumulator

S address of a memory locationS address of a memory location

CI is the address of the current instructionCI is the address of the current instruction

Tom Kilburn’s First Program, find the highest proper factor of any number


EDSACEDSAC

► EDSAC was developed EDSAC was developed by Maurice Wilkes at by Maurice Wilkes at Cambridge UniversityCambridge University

► Work started in 1947 Work started in 1947 after Wilkes attended after Wilkes attended the 1946 Moore the 1946 Moore School lecturesSchool lectures

► Patterned after EDVACPatterned after EDVAC► Contained 3000 tubes, Contained 3000 tubes,

600 operations / sec600 operations / sec► First program First program

executed May 1949executed May 1949

EElectronic lectronic DDelay elay SStorage torage AAutomatic utomatic CCalculatoralculator


EDSACEDSAC► EDSAC MemoryEDSAC Memory

EDSAC utilized EDSAC utilized ultrasonic mercury ultrasonic mercury delay line tubes for delay line tubes for its memoryits memory

32 tanks, each of 32 tanks, each of which contained 32 which contained 32 numbers of 17 bits numbers of 17 bits each (1024 storage each (1024 storage locations)locations)

Two can be combined Two can be combined to handle a number to handle a number 35 bits long35 bits long


EDSACEDSAC► Control DeskControl Desk

Contained 6 CRTs Contained 6 CRTs used to monitor the used to monitor the contents of memorycontents of memory

5-hole punched 5-hole punched tape for inputtape for input

Output was to a Output was to a teleprinterteleprinter

Used a telephone-Used a telephone-type dial to input type dial to input single decimal single decimal digitsdigits


EDSACEDSAC► A very good Windows A very good Windows

simulator is available simulator is available for the EDSACfor the EDSAC

► Written at Warwick Written at Warwick universityuniversity

► Complete Complete instructions on use instructions on use and sample programs and sample programs are includedare included

► Demonstration?Demonstration?

Analog / Electronic Analog / Electronic (Transistor)(Transistor) Computers Computers

1950s - 1960s1950s - 1960s

Analog / Electronic (Transistor / IC)Analog / Electronic (Transistor / IC)

► In the 50s and In the 50s and 60s (even 70’s) 60s (even 70’s) electronic electronic versions of the versions of the analog computer analog computer were availablewere available

► Generally Generally consisted of Op consisted of Op Amps with the Amps with the ability to ability to connect them to connect them to add, subtract, add, subtract, multiply multiply integrate, etc.integrate, etc.

Hobby / TrainingHobby / TrainingComputersComputers

1950s - 1960s1950s - 1960s

Hobby / Training computersHobby / Training computers► Heathkit produced several analog Heathkit produced several analog

computer kits in the 50’scomputer kits in the 50’s► One shown is the ES seriesOne shown is the ES series► Tube operated, amplifier basedTube operated, amplifier based► 15 amplifiers, 3 I.C. power 15 amplifiers, 3 I.C. power

supplies, 30 coefficient supplies, 30 coefficient potentiometerspotentiometers

► Full kit listed for $945 in 1956 Full kit listed for $945 in 1956 (about $7,400 today)(about $7,400 today)

Hobby / Training computersHobby / Training computers

► GE produced a simple GE produced a simple educational analog educational analog computercomputer

► Model EF-140 shownModel EF-140 shown► Used potentiometers and Used potentiometers and

cardboard dials with scale cardboard dials with scale markingsmarkings

► Solved equations like Y = Solved equations like Y = 3X, or Z = X / Y3X, or Z = X / Y

► $29.29, used 4 ‘D’ batteries$29.29, used 4 ‘D’ batteries► Used transistors for Used transistors for

amplifier / oscillator / null amplifier / oscillator / null indicatorindicator


► Digicomp 1Digicomp 1► Produced in 1965 by Produced in 1965 by

ESR Inc. for $5.95 ESR Inc. for $5.95 (about $40 today)(about $40 today)

► Taught basics of Taught basics of boolean algebra, writing boolean algebra, writing “programs”, binary “programs”, binary additionaddition

► Possible to play game of Possible to play game of “nim”“nim”

► 50 page instruction 50 page instruction manual includedmanual included


►Bell Labs “Cardiac” Bell Labs “Cardiac” probably the least probably the least expensive of any expensive of any “computer”“computer”

►ManuallyManually operated operated►Designed to teach Designed to teach

the basics of digital the basics of digital computer operationcomputer operation

The EndThe End

Thanks!Thanks!

ResourcesResources► WebsitesWebsites

Computer History MuseumComputer History Museum► http://www.computerhistory.orghttp://www.computerhistory.org ► Mountain View, CAMountain View, CA

London Science MuseumLondon Science Museum► http://http://www.sciencemuseum.org.ukwww.sciencemuseum.org.uk//

Tim Robinson’s Differential Analyzer - Tim Robinson’s Differential Analyzer - MeccanoMeccano► http://http://

www.meccano.us/differential_analyzers/rowww.meccano.us/differential_analyzers/robinson_dabinson_da//

► BooksBooks ““Bit by Bit an Illustrated History of Bit by Bit an Illustrated History of

Computers” by Stan AugartenComputers” by Stan Augarten ““The Moore School Lectures” Vol 9, The The Moore School Lectures” Vol 9, The

MIT Press, © 1985MIT Press, © 1985 ““The Origins of Digital Computers” The Origins of Digital Computers”

Selected Papers, Springer Verlag, 2Selected Papers, Springer Verlag, 2ndnd ed ed © 1970© 1970

A Brief Tour of The History of Computers Presented by Kevin Nichols KA7OFR.

Documents

electronic computers

term computer

specific computers

stored program computer

history of computers

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selected computers

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