Introduction to Computers - Part 1 - Introduction and …upperbeac.acfe.vic.edu.au/file/view/Introduction to...1674, Germany, LiebnizStep Reckoner 13 Invented by Baron Gottfried von

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Introduction

One definition of a computer is that it is a general purpose electronic device which can be used to “process information”. This just means that, by executing different sets of instructions it’s able to carry out a wide range of different tasks. By comparison, other electronic devices are usually dedicated to a single task (e.g. a TV set). A computer is able to be so flexible because it can READ, STORE and EXECUTE pre-defined set of instructions which we call computer PROGRAMS. By running these different programs a computer can be used to perform many useful functions, including…CD/DVD player, calculator, address book, texting device, calendar, organiser, book reader, games console, photo album, picture editor, video editor, slide viewer, fax machine, atlas, encyclopaedia, cash book, sound editor, music player, etc, etc, etc. The range and variety of tasks which a computer can execute is really only restricted by the imagination of the person creating the programs, the “programmer”.

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A Brief History of Computers

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It’s interesting to look back at some of the inventions and developments which

have led to the modern general purpose computer and perhaps the very first

example is the brain. In many respects the brain can be considered as the first

computer, or what we might call “computer generation zero”. The brain is

actually very good at “fuzzy logic”. This means it is able to successfully draw

conclusions based on vague, ambiguous or incomplete information. However, it

has faily limited computational (processing) power and it’s memory functions

tend to be selective and subjective (and therefore generally unreliable). Early

man quickly developed tools to extend the functions of the brain. Some of these

‘brain tools’ are still around today.

C30,000 BC, Europe, The Tally System

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These wolf bones were discovered in Western Europe and are estimated to be

about 30,000 years old! They contain man-made scratches arranged in groups of

5. This is the first evidence we have found of the use of a number recording

system and the ‘tally system’ it depicts is still in use today!

C1000 BC, Babylonia, The Abacus

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Invented by the Babylonians in about 1,000 BC, the abacus is the world’s first

known mechanical calculator. It can be used to add, subtract, multiply & divide.

In the hands of a skilled operator it is faster than a pocket calculator and is still

used in many parts of Asia.

C1500, Italy, Mechanical Calculator

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In 1967 two unknown works by Leonardo da Vinci were discovered in Madrid

(museum officials claimed that manuscripts were “not lost, but just misplaced”).

The notebooks (now known as the "Codex Madrid”) were dated to approx 1500

AD and contained an apparent design for a mechanical calculator. A controversial

working replica was built in 1968 by Dr Roberto Guatelli but objectors claimed

that the original was not really a calculator but a “ratio machine” which could

never work because of the friction forces generated. The replica is now lost but is

believed to be held in storage somewhere by IBM.

1594, England, Napier’s Bones

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This device was invented in England by Charles Napier. It simplified the process

of multiplication and division by converting these to addition and subtraction. It

can be considered as the first printed multiplication tables

1622, England, The Slide Rule

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Invented by William Oughtred in England in 1622. Two logarithmic scales allow

multiplication and division. This is an analogue (not digital) device and is limited

in its accuracy.

The slide rule was still in common use until the 1970s.

1623, Germany, Schickard mechanical calculator

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Invented by Wilhelm Schickard in Germany this device was a mechanical

implementation of Napier’s Bones. It could be used to add, subtract, multiply and

divide. The original was destroyed in a fire and remained unknown for 300 years

but was reconstructed in 1960.

1642, France, Pascaline mechanical calculator

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This device was invented by Blaise Pascal (1623-1662, a French mathematician

and philosopher) at the age of 19. It was also known as the ‘Arithmatique’. It

used a system of weights and could handle numbers up to 999,999.999.

1674, Germany, Liebniz Step Reckoner

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Invented by Baron Gottfried von Liebniz in Germany and based on the earlier

work of Pascal, this device was able to add, subtract, multiply, divide and

calculate square roots.

"It is unworthy of excellent men to lose hours like slaves in the labour of

calculation, which could be safely relegated to anyone else if machines were

used."

- Baron Gottfried von Liebniz

1804, France, Jacquard Loom (data storage)

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Invented by Joseph-Marie Jacqard (1752-1854) in France in 1804, the Jacquard

Loom stored carpet patterns on punched cards. The cards were then read by a

carpet loom to faithfully reproduce the pattern designed by the original

“programmer”. This device is interesting in that it was the first use of punched

cards for the storage of data/instructions. A device which would be taken up later

for use with electronic computers.

1822, England, Babbage Difference Engine

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The Difference Engine was actually conceived in 1786 by J H Mueller but was

rediscovered by Charles Babbage in England in 1822. Babbage presented a

design to the Royal Astronomical Society and the device was built from 1855

onwards. Along with the more general ‘Analytical Engine’ this is considered to

be the first general purpose “programmable” calculator. It was designed to

calculate polynomial functions. A working replica of the Difference Engine was

built in 1991 by the British Museum. It works perfectly and can still be seen

today.

Ada Byron, Countess of Lovelace (1815-1852)

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Ada Byron was the daughter of Anne Isobelle Millbanke and the poet Byron (she

never actually met her father, Lord Byron, who died in Greece in 1823). Ada was

a close friend of Charles Babbage and was a skilled mathematician and scientist.

She understood the potential of the Difference Engine and was responsible for

setting up and programming the device. She is considered to be the first real

computer program.

1874, US, The Typewriter

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The typewriter was invented by US engineer Christopher Latham Sholes (1819-

1890) and was first patented in 1868. The first commercial typewriter was

produced by Remington & Sons in the USA. The computer keyboard that we use

today (with a few evolutionary changes) is a direct descendant of Sholes

typewriter.

It’s interesting to note that the layout of the standard qwerty keyboard was

designed to slow down typists, as early mechanical typewriters tended to jam

easily.

1890, US, The Hollerith Tabulator

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The tabulator was invented by Herman Hollerith in the USA and was used for

processing information which was held on punched cards (thank you, Monsieur

Jacqard). It was used to sort data from the 1890 US Census.

In 1924 the Hollerith Company changed its name to International Business

Machines (IBM), and would go on to become the largest computer company in

the world.

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First Generation Computers

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ENIAC (Electronic Numerical Integrator and Calculator) is an example of the

first generation of ‘true’ general purpose electronic computers, which were

produced in the early 1940s. ENIAC was built at the University of Pennsylvania,

in the US, and cost US$500,000. It filled a large room, weighed 30 tons,

consumed 200Kw of power and used over 19,000 vacuum tubes (valves) to store

data. It consisted of 42 panels, each 9ft x 2ft x 1ft. It was programmed using

3,000 switches and wiring connections, read its input from a punched card reader,

and output its results to a card punch.

ENIAC was used to calculate ballistic trajectories (other first generation

computers were used to crack cipher codes, etc). It was eventually shut down

after 10 years of successful operation.

Second Generation Computers

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UNIVAC (or UNIVersal Automatic Computer) is an example of second

generation computers, which became available in the 1950s. Instead of valves,

second generation computers were built using transistors. This made them

smaller, lighter, less power-hungry and MUCH more reliable. UNIVAC only

weighed 13 tonnes.

UNIVAC was developed in the USA and was probably the first commercially

available computer. It was used to correctly predict the outcome of the 1952 US

presidential election (which was won by Dwight Eisenhower).

Third Generation Computers

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Third generation computers were produced from 1960 onwards and were built

using ‘integrated circuits’ or ‘chips’. This made them very much smaller and

lighter and meant that they consumed much less power than previous, generation

2, computers. The IBM System 360 is a typical example of a third generation

computer. It was the first commercially available mainframe computer which

came in a range of compatible models. The range cost US$5B to develop. Third

generation computers were used for general business use by many banks,

insurance companies, manufacturers, etc. The increasing miniaturization of

electronics eventually led to the development of the ‘microprocessor’, effectively

a computer implemented within a single integrated circuit chip.

Three-and-a-Half/Fourth Generation Computers

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The world’s first commercial microprocessor was the Intel 4040, which was

produced by Intel Corporation in US and released in Feb 1971. Although referred

to as fourth generation technology the ‘computer-on-a-chip’ did not represent a

significant breakthrough in electronics, but rather an evolution of earlier

technology. This is why it is sometimes referred to as “three and a half”

generation. The Intel 404 had a processing speed rated at 60 KHz, which meant it

was capable of executing about 60,000 instructions every second. The 4040 was

later replaced by the 8086, 8088, 80386, and Pentium processors.

Microcomputers

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Because of the (relatively) low cost and increasing availability of

microprocessors, a range of much smaller general purpose computers based on

these microprocessors began to be offered for sale during the 1970s.

1975-1980

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Most microcomputers of the time were bought by home hobbyists purely for their

own interest and amusement. The Altair 8800 was sold in kit form through

electronics magazines.

The Xerox Alto

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The first device considered to be a true “Personal Computer” was built in 1973

by Xerox PARC in Palo Alto, USA and was known as the Xerox Alto. It was

never actually sold as a commercial product but several thousand were built and

distributed. It was based on a Texas Instruments 74181 microprocessor, had up to

512KB of memory, used a magnetic hard disk for storage and had a black and

white CRT display. The display unit was in ‘portrait’ form to facilitate the display

of document pages.

1975 – IBM 5100

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The IBM 5100 was introduced in September 1975. It weighed 50 pounds and did

NOT use an integrated circuit but had a proprietary 16-bit processor called

PALM. It was basically a cut-down version of the IBM System 360 mainframe

computer, had up to 64KB of memory, an in-built 5-inch CRT display and

initially used cartridge tape storage. Later models used floppy disk storage. The

5100 was intended to appeal to business users at a time when home devices such

as those produced by Sinclair, Atari. Apple, etc, still dominated the market.

1981 – The IBM (5150) Personal Computer

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The IBM Personal Computer was released in August 1981 and was a true 4th

generation computer, being built with integrated circuits (unlike its predecessor,

the 5100). To reduce its commercial exposure in the development and production

of the 5150, IBM used many off-the-shelf (i.e. non-proprietary) components in its

design. The PC had a 4.77MHz Intel 8088 microprocessor and 640KB of

memory and the software to drive the PC came from a small start-up software

company called ‘Microsoft’. The PC introduced the now-familiar 3-box concept

of screen, system unit and keyboard (the mouse was added later). It originally

cost up to US$20,000 each to purchase and sold well to businesses. However, the

non-proprietary open architecture of its design was quickly copied and the ‘IBM

PC’ was subsequently ‘cloned’ in millions. It eventually outsold all other designs

for personal computers and become the world ‘de-facto’ standard.

Since IBM had not limited them to an exclusive supply contract, Microsoft was

carried along with the tide to become the biggest software company in the world.

The PC Today

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The IBM PC was so successful that modern PCs are almost indistinguishable

from the original 1981 IBM 5150 model.

Although processing power and storage capacities have increased beyond all

recognition since the 1970s the underlying technology of LSI (large scale

integration) or VLSI (very large scale integration) microchips has remained

basically the same. Because of this, most of today's computers are still regarded

as being fourth generation.

Types of Computer

Personal computers can come in a number of different shapes and sizes (form

factors) while sharing the same basic components and design. For example the

IBM PC may come as a desktop model, laptop or notebook model, netbook,

tablet, handheld or smart phone.

Other types of computer may be referred to as server, midrange, mainframe, or

supercomputer but may still be based on the same underlying architecture.

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Laptop/Notebook Computer

Laptops (notebook computers) have all of the same basic components as the

larger desktop but these components have been specially engineered to fit into a

smaller case. For this reason the components are often custom-designed and built

and so can be more expensive than those used for desktops. Laptops are, by

design, lighter and therefore more portable than desktops. They are usually less

powerful because they have less room for the cooling fans used in larger

machines. Laptops and netbooks are also able to run on batteries. Netbooks are

similar in design to notebooks but are smaller, lighter and more portable again.

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Tablet Computers

Tablets computers are a cross between netbooks and hand-held devices. They are

simpler to use and have no keyboard but have a touch-sensitive screen, from

which they are controlled.

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Handheld Devices, Smartphones, etc.

These include small devices such as the Pocket PC, PDA, etc, as well as mobile

phones such as the iPhone. They have less storage than other types of computer

are less powerful but are VERY portable. They will often run a variation of the

same software used on desktop and notebook computers.

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Other computing terms you may hear …

Servers are basically the same as desktops but tend to be more powerful, have

more memory and storage, have more network connections, and are usually

dedicated to performing a single task (e.g. email servers).

Mid-Range computers are very powerful. They are used by business and may

actually consist of multiple PC processing units within a single package.

Mainframe computers are traditional large commercial computer, still often used

by banks & insurance companies for processing large numbers of commercial

transactions (“on-line transaction processing”) e.g. ATM networks.

Super-Computer is a generic term for a very powerful computer processing

capability, usually consisting of a network of smaller computers operating in

parallel. They are for commercial number-crunching, e.g. weather forecasting,

CGI, etc. The Internet is a the largest supercomputer in the world.

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