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The Fourth Generation, 1971-Present: The Microprocessor
Through the 1970s, computers gained dramatically in speed, reliability, and storage capacity, but entry into the fourth generation was evolutionary rather than revolutionary. The fourth generation was, in fact, an extension of third-generation technology. That is, in the early part of the third generation, specialized chips were developed for computer memory and Iogic. Thus, all the ingredients were in place for the next technological development, the general-purpose processor-on-a-chip, otherwise known as the microprocessor. First developed by an Intel Corporation design team headed by Ted Hoff in 1969, the microprocessor became commercially available in 1971.
Nowhere is the pervasiveness of computer power more apparent than in the explosive use of the microprocessor. In addition to the common applications of digital watches, pocket calculators, and microcomputers —
small home and business computers — microprocessors can be anticipated in virtually every machine in the home or business. (To get a sense of how far we have come, try counting up the number of machines, microprocessor controlled or not, that are around your house. Would more than one or two have been in existence 50 years ago?)
The 1970s saw the advent of large-scale integration (LSI). The first LSI chips contained thousands of transistors; later, it became possible to place first tens and then hundreds of thousands of transistors on a single chip. LSI technology led to two innovations: embedded computers, which are incorporated into other appliances, such as cameras and TV sets, and microcomputers or personal computers, which can be bought and used by individuals. In 1975, very large scale integration (VLSI) was achieved. As a result, computers today are 100 times smaller than those of the first generation, and a single chip is far more powerful than ENIAC.
Computer environments have changed, with climate-controlled rooms becoming less necessary to ensure reliability; some recent models (especially minicomputers and microcomputers) can be placed almost anywhere.
Large computers, of course, did not disappear just because small computers entered the market. Mainframe manufacturers have continued to develop powerful machines, such as the UNIVAC 1100, the IBM 3080 series, and the supercomputers from Gray.
Countries around the world have been active in the computer industry; few are as renowned for their technology as Japan. The Japanese have long been associated with chip technology, but recently they announced an entirely new direction.