By the early 1970s technology was racing to keep up with the thirst for electronic brainpower in corporations, universities, government agencies, and other such big traffickers in data. Vacuum-tube switches had given way a decade earlier to smaller, cooler, less power-hungry transistors, and now the transistors, along with other electronic components, were being packed together in ever-increasing numbers on silicon chips. In addition to their processing roles, these chips were becoming the technology of choice for memory, the staging area where data and instructions are shuttled in and out of the computer—a job long done by arrays of tiny ferrite doughnuts that registered data magnetically. Storage—the part of a computing system where programs and data are kept in readiness-had gone through punched card, magnetic tape, and magnetic drum phases; now high-speed magnetic disks ruled. High-level programming languages such as FORTRAN (for science applications), COBOL (for business), and BASIC (for beginners) allowed software to be written in English-like commands rather than the abstruse codes of the early days. Some computer makers specialized in selling prodigiously powerful machines to such customers as nuclear research facilities or aerospace manufacturers. A category called supercomputers was pioneered in the mid-1960s by Control Data Corporation, whose chief engineer, Seymour Cray, designed the CDC 6600, a 350,000-transistor machine that could execute 3 million instructions per second. The price: $6 million. At the opposite end of the scale, below big mainframe machines like those made by IBM, were minicomputers, swift enough for many scientific or engineering applications but at a cost of tens of thousands rather than hundreds of thousands of dollars. Their development was spearheaded by Kenneth Olsen, an electrical engineer who cofounded Digital Equipment Corporation and had close ties to MIT.
Then, with the arrival of the humble Altair in 1975, the scale suddenly plunged to a level never imagined by industry leaders. What made such a compact, affordable machine possible was the microprocessor, which concentrated all of a computer's arithmetical and logical functions on a single chip—a feat first achieved by an engineer named Ted Hoff at Intel Corporation in 1971. After the Intel 8080 microprocessor was chosen for the Altair, two young computer buffs from Seattle, Bill Gates and Paul Allen, won the job of writing software that would allow it to be programmed in BASIC. By the end of the century the company they formed for that project, Microsoft, had annual sales greater than many national economies. Then, with the arrival of the humble Altair in 1975, the scale suddenly plunged to a level never imagined by industry leaders. What made such a compact, affordable machine possible was the microprocessor, which concentrated all of a computer's arithmetical and logical functions on a single chip—a feat first achieved by an engineer named Ted Hoff at Intel Corporation in 1971. After the Intel 8080 microprocessor was chosen for the Altair, two young computer buffs from Seattle, Bill Gates and Paul Allen, won the job of writing software that would allow it to be programmed in BASIC. By the end of the century the company they formed for that project, Microsoft, had annual sales greater than many national economies. Nowhere was interest in personal computing more intense than in the vicinity of Palo Alto, California, a place known as Silicon Valley because of the presence of many big semiconductor firms. Electronics hobbyists abounded there, and two of them—Steve Jobs and Steve Wozniak—turned their tinkering into a highly appealing consumer product: the Apple II, a plastic-encased computer with a keyboard, screen, and cassette tape for storage. It arrived on the market in 1977, described in its advertising copy as "the home computer that's ready to work, play, and grow with you." Few packaged programs were available at first, but they soon arrived from many quarters. Among them were three kinds of applications that made this desktop device a truly valuable tool for business—word processing, spreadsheets, and databases. The market for personal computers exploded, especially after IBM weighed in with a product in 1981. Its offering used an operating system from Microsoft, MS-DOS, which was quickly adopted by other manufacturers, allowing any given program to run on a wide variety of machines. The next 2 decades saw computer technology rocketing ahead on every front. Chips doubled in density almost annually, while memory and storage expanded by leaps and bounds. Hardware like the mouse made the computer easier to control; operating systems allowed the screen to be divided into independently managed windows; applications programs steadily widened the range of what computers could do; and processors were lashed together—thousands of them in some cases-in order to solve pieces of a problem in parallel. Meanwhile, new communications standards enabled computers to be joined in private networks or the incomprehensibly intricate global weave of the Internet. Where it all will lead is unknowable, but the rate of advance is almost certain to be breathtaking. When the Mark I went to work calculating ballistics tables back in 1943, it was described as a "robot superbrain" because of its ability to multiply a pair of 23-digit numbers in 3 seconds. Today, some of its descendants need just 1 second to perform several hundred trillion mathematical operations—a performance that, in a few years, will no doubt seem slow.
1936 "A Symbolic Analysis of Relay and Switching Circuits" Electrical engineer and mathematician Claude Shannon, in his master’s thesis, "A Symbolic Analysis of Relay and Switching Circuits," uses Boolean algebra to establish a working model for digital circuits. This paper, as well as later research by Shannon, lays the groundwork for the future telecommunications and computer industries.
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