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Basically, each metal ring, activated by the electric impulse answers 1 or 0, meaning that it either does or does not represent a portion of the binary numeral sought. If the computer wishes to use the number 87, for example, it might get positive responses from the rings that made up the numbers 1, 2, 4, 16 and 64—for a total of 87—while receiving negative responses from the other rings. In a vast series of such instantaneous actions, thousands of transistors in the machine turn on and off in response to the electric impulses until the machine has assembled the information requested and performed the necessary calculations. The computer thus reaches a decision on demand by counting a great many combinations of binary numbers that stand for the coded and stored information. Today's newest computers are capable of performing calculations in billionths of a second.
Reliable & Cool. From the simple abacus of ancient times down through the mechanical adding machine, man has for centuries moved toward the computer. As early as 1671 Gottfried Leibnitz sought unsuccessfully to invent a mechanical calculating machine. "It is unworthy of excellent men," he wrote, "to lose hours like slaves in the labor of calculation." In 1834 an eccentric Englishman named Charles Babbage conceived the idea of a steam-driven "Analytical Engine" that in many details anticipated the basic principles of modern computers. But not until 1944 did man invent the first true computer: the Mark I, developed by Harvard Professor Howard Aiken and used to compute weapon trajectories for the U.S. Navy.
By today's standards, Mark I was as slow and awkward as a manual adding machine. In two years it was shoved aside by the University of Pennsylvania's celebrated ENIAC, which, as the first electronic computer, used 18,000 vacuum tubes as circuits and quick-acting switches. Though they were a big advance, vacuum tubes proved too expensive, too unreliable and too bulky: ENIAC weighed 30 tons and took up 1,500 sq. ft. of floor space. Until 1954, when Remington Rand (now Sperry Rand) first sold its UNIVAC to industry, the few computers in the U.S. were largely experimental and custom designed.
Computers did not really hit their stride until transistors and other solidstate components—tiny, reliable and cool-running—took over from vacuum tubes in 1958. The state of the art has been speeded considerably by the U.S. military and its pressing demands for larger, faster computers. One of today's computers can make more calculations in one hour than a Yankee Stadium full of scientists could make in a man's lifetime. Some of the more sophisticated machines can multiply 500,000 ten-digit numbers in one second. Even if no further advances were made in computer technology, some scientists maintain, the computer has provided enough work and opportunities for man for another thousand years.