The Computer Society: Science: The Numbers Game

From a roomful of knitting ladies to a superchilled "brain "

For the young electronics engineer at the newly formed Intel Corp., it was a challenging assignment. Fresh out of Stanford University, where he had been a research as sociate, M.E. ("Ted") Hoff in 1969 was placed in charge of producing a set of miniature components for programmable desk top calculators that a Japanese firm planned to market. After studying the circuitry proposed by the Japanese designers, the shy, self-effacing Hoff knew that he had a problem. As he recalls: "The calculators required a large number of chips, all of them quite expensive, and it looked, quite frankly, as if it would tax all our design capability."

Pondering the difficulty, Hoff was suddenly struck by a novel idea. Why not place most of the calculator's arithmetic and logic circuitry on one chip of silicon, leaving mainly input-output and programming units on separate chips? It was a daring conceptual move. After wrestling with the design, Hoff and his associates at Intel finally concentrated nearly all the elements of a central processing unit (CPU), the computer's electronic heart and soul, on a single silicon chip.

Unveiled in 1971, the one-chip CPU — or microprocessor — contained 2,250 transistors in an area barely a sixth of an inch long and an eighth of an inch wide. In computational power, the micro processor almost matched the monstrous ENIAC — the first fully electronic computer, completed in 1946 — and performed as well as an early 1960s IBM machine that cost $30,000 and required a CPU that alone was the size of a large desk. On his office wall, Hoff still displays Intel's original advertisement: "Announcing a new era of integrated electronics ... a microprogrammable computer on a chip."

Intel's little chip had repercussions far beyond the pocket-calculator and minicomputer field. It was so small and cheap that it could be easily incorporated into almost any device that might benefit from some "thinking" power: electric typewriters with a memory, cameras, elevator controls, a shopkeeper's scales, vending machines, and a huge variety of household appliances. The new chip also represented another kind of breakthrough: because its program was on a different chip, the microprocessor could be "taught" to do any number of chores. All that had to be done was to substitute a tiny program chip with fresh instructions. In a memorable display of this versatility, the Pro-Log Corp. of Monterey, Calif., built what was basically a digital clock. But by switching memory chips and hitching it to a loudspeaker, it became first a "phonograph," playing the theme from The Sting, then an electric piano.