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The first generation of computers (1940–1955)
Was a time of vacuum tube
technology and computers the size of classrooms. Each computer was unique in
structure and purpose. There was little need for standard operating system software
because each computer’s use was restricted to a few professionals working on
mathematical, scien- tific, or military applications, all of whom were familiar with the
idiosyncrasies of their hardware. -
Second-generation computers.
Were developed to meet the needs of
new markets—government and business researchers. The business environment
placed much more importance on the cost effectiveness of the system. Computers
were still very expensive, especially when compared to other office equipment (the
IBM 7094 was priced at $200,000). Therefore, throughput had to be maximized to
make such an investment worthwhile for business use, which meant dramatically
increasing the usage of the system. -
Third-generation computers date from the mid-1960s.
They were designed with
faster CPUs, but their speed still caused problems when they interacted with printers
and other I/O devices that ran at slower speeds. The solution was multiprogramming,
which introduced the concept of loading many programs at one time and sharing
the attention of a single CPU. -
Fourth-generation computers.
The period of fourth generation was from 1971-1980. Computers of fourth generation used Very Large Scale Integrated circuits. VLSI circuits having about 5000 transistors and other circuit elements with their associated circuits on a single chip made it possible to have microcomputers of fourth generation.
