The Third Generation: Integrated Circuit Computers (1965–1980)

The real explosion in computer use came with the integrated circuit generation.

Jack Kilby invented the integrated circuit (IC) or

microchip

, made of germanium.

Six months later, Robert Noyce (who had also been working on integrated circuit

design) created a similar device using silicon instead of germanium. This is the

silicon chip upon which the computer industry was built. Early ICs allowed

IC technology also allowed for the development of more powerful supercomputers.

Seymour Cray took what he had learned while building the CDC 6600 and

started his own company, the Cray Research Corporation. This company produced

a number of supercomputers, starting with the $8.8 million Cray-1, in

1976. The Cray-1, in stark contrast to the CDC 6600, could execute over 160 million

instructions per second and could support 8 megabytes of memory.

dozens of transistors to exist on a single silicon chip that was smaller than a single

“discrete component” transistor. Computers became faster, smaller, and

cheaper, bringing huge gains in processing power. The IBM System/360 family

of computers was among the first commercially available systems to be built

entirely of solid-state components. The 360 product line was also IBM’s first

offering where all of the machines in the family were compatible, meaning they

all used the same assembly language. Users of smaller machines could upgrade to

larger systems without rewriting all of their software. This was a revolutionary

new concept at the time.

The IC generation also saw the introduction of time-sharing and multiprogramming

(the ability for more than one person to use the computer at a time).

Multiprogramming, in turn, necessitated the introduction of new operating systems

for these computers. Time-sharing minicomputers such as DEC’s PDP-8 and

PDP-11 made computing affordable to smaller businesses and more universities.

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