Introduction to Computers - Part 1 - Introduction and...
Transcript of Introduction to Computers - Part 1 - Introduction and...
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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
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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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