Information Technology Reference
In-Depth Information
1
Introduction
1.1
Pre-PC Development
One of the first occurrences of computer technology occurred in the USA in the 1880s. It
was due to the American Constitution demanding that a survey is undertaken every 10 years.
As the population in the USA increased, it took an increasing amount of time to produce the
statistics. By the 1880s, it looked likely that the 1880 survey would not be complete until
1890. To overcome this, Herman Hollerith (who worked for the Government) devised a ma-
chine which accepted punch cards with information on them. These cards allowed a current
to pass through a hole when there was a hole present.
Hollerith's electromechanical machine was extremely successful and used in the 1890
and 1900 Censuses. He even founded the company that would later become International
Business Machines (IBM): CTR (Computer Tabulating Recording). Unfortunately, Hol-
lerith's business fell into financial difficulties and was saved by a young salesman at CTR,
named Tom Watson, who recognized the potential of selling punch card-based calculating
machines to American business. He eventually took over the company Watson, and, in the
1920s, he renamed it International Business Machines Corporation (IBM). After this, elec-
tromechanical machines were speeded up and improved. Electromechnical computers would
soon lead to electronic computers, using valves.
The first electronic computers were developed, independently, in 1943; these were the
'Harvard Mk I' and Colossus. Colossus was developed in the UK and was used to crack the
German coding system (Lorenz cipher), whereas 'Harvard Mk I' was developed at Harvard
University and was a general-purpose electromechanical programmable computer. These led
to the first generation of computers which used electronic valves and used punched cards for
their main, non-volatile storage.
The world's first large electronic computer (1946), containing 19 000 values was built at
the University of Pennsylvania by John Eckert during World War II. It was called ENIAC
(Electronic Numerical Integrator and Computer) and it ceased operation in 1957. By today's
standards, it was a lumbering dinosaur and by the time it was dismantled it weighed over 30
tons and spread itself over 1500 square feet. Amazingly, it also consumed over 25 kW of
electrical power (equivalent to the power of over 400, 60 W light bulbs), but could perform
over 100 000 calculations per second (which is reasonable, even by today's standards). Un-
fortunately, it was unreliable, and would only work for a few hours, on average, before a
valve needed to be replaced. Faultfinding, though, was easier in those days, as a valve, which
was working, would not glow, and would be cold to touch.
Valves were fine and were used in many applications, such as in TV sets and radios, but
they were unreliable and consumed great amounts of electrical power, mainly to the heating
element on the cathode. By the 1940s, several scientists at the Bell Laboratories were inves-
tigating materials called semiconductors, such as silicon and germanium. These substances
only conducted electricity moderately well, but when they where doped with impurities their
1
