Hardware History Overview
Modern computing can probably be
traced back to the 'Harvard Mk I'
and Colossus (both of 1943).
Colossus was an electronic
computer built in Britain at the
end 1943 and designed to crack
the German coding system -
Lorenz cipher. The 'Harvard Mk I'
was a more general purpose
electro-mechanical programmable
computer built at Harvard
University with backing from IBM.
These computers were among the
first of the 'first generation'
computers.
First generation computers were
normally based around wired
circuits containing vacuum valves
and used punched cards as the
main (non-volatile) storage
medium. Another general purpose
computer of this era was
'ENIAC' (Electronic Numerical
Integrator and Computer) which
was completed in 1946. It was
typical of first generation
computers, it weighed 30 tonnes
contained 18,000 electronic valves
and consumed around 25KW of
electrical power. It was, however,
capable of an amazing 100,000
calculations a second.
The next major step in the
history of computing was the
invention of the transistor in 1947.
This replaced the inefficient
valves with a much smaller and
more reliable component.
Transistorised computers are
normally referred to as 'Second
Generation' and dominated the late
1950s and early 1960s. Despite
using transistors and printed
circuits these computers were still
bulky and strictly the domain of
Universities and governments.
The explosion in the use of
computers began with 'Third
Generation' computers. These
relied Jack St. Claire Kilby's
invention - the integrated circuit or
microchip; the first integrated
circuit was produced in September
1958 but computers using them
didn't begin to appear until 1963.
While large 'mainframes' such as
the I.B.M. 360 increased storage
and processing capabilities further,
the integrated circuit allowed the
development of Minicomputers that
began to bring computing into
many smaller businesses. Large
scale integration of circuits led to
the development of very small
processing units, an early example
of this is the processor used for
analyising flight data in the US
Navy's F14A TomCat' fighter jet.
This processor was developed by
Steve Geller, Ray Holt and a team
from AiResearch and American
Microsystems.
On November 15th, 1971, Intel
released the world's first
commercial microprocessor, the
4004. Fourth generation computers
were developed, using a
microprocessor to locate much of
the computer's processing abilities
on a single (small) chip. Coupled
with one of Intel's inventions - the
RAM chip (Kilobits of memory on
a single chip) - the microprocessor
allowed fourth generation
computers to be even smaller and
faster than ever before. The 4004
was only capable of 60,000
instructions per second, but later
processors (such as the 8086 that
all of Intel's processors for the
IBM PC and compatibles is based)
brought ever increasing speed and
power to the computers.
Supercomputers of the era were
immensely powerful, like the
Cray-1 which could calculate 150
million floating point operations
per second. The microprocessor
allowed the development of
microcomputers, personal
computers that were small and
cheap enough to be available to
ordinary people. The first such
personal computer was the MITS
Altair 8800, released at the end of
1974, but it was followed by
computers such as the Apple I &
II, Commodore PET and eventually
the original IBM PC in 1981.
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, so it is widely regarded
that most of today's computers
still belong to the fourth
generation.