Reference STATE OF THE ART Stan Augarten

ISBN 0-89919-195-9

Photo of
The First 8-bit Microprocessor
The 8008


A few months after Busicom approached Intel to design the innards of a new programmable calculator, Computer Terminals Corporation (CTC), a Texas outfit, came by with a similar proposal. The Texas firm, now called Datapoint, asked Intel to design a set of ICs for an intelligent terminal (a monitor-equipped computer terminal with some computing power of its own) then on the drawing boards. Intel again suggested a microprocessor-based system, but the 4004 being developed for Busicom (p. 30) wasn't powerful enough. Another, more advanced chip, was needed.

  The 4004, being a 4-bit microprocessor, can handle data in chains of only four bits at a time. And it can generate only a very limited number of unique addresses for the data stored in memory, a mere 1,280 nibbles. Although quite adequate for most low-power applications, like running a handheld calculator, a 4-bit microprocessor is unable to meet the greater data processing requirements of an intelligent terminal. For this, an 8-bit chip is necessary.

  So Intel came up with the 8008, an 8-bit microprocessor designed by Hal Feeney, Ted Hoff, Frederico Faggin, and Stan Mazor. With some 3,300 MOS transistors - a thousand more than the 4004 had - it could execute some 30,000 operations a second and address 16K bytes of memory. Nevertheless, the 8008 was rejected by CTC, chiefly because it was too slow and required many supporting chips. Intel subsequently offered the 8008 on the open market, where it was a great success.

  It soon became obvious to Intel and other semiconductor makers that there was an almost limitless number of applications for microprocessors, and the race was on to create ever more powerful models. Because both the 4004 and the 8008 had been designed for specific machines, Intel was at first only dimly aware of the microprocessor's revolutionary potential. Eventually, however, it became abundantly clear that these extraordinary creations could not only enhance the power of calculators but also change the world.

The 8008 can executed a single operation, like the addition of two 8-bit number, in 12.5 millionths of a second. The chip multiplies by repeated addition, a time-consuming process. The grids on the right are registers; most of the rest of the chip is occupied by logic circuits. Actual size: 0.125 x 0.170 inches. Photo of


©Copyright Stan Augarten
This book is provided for general reference. The National Museum of American History and the Smithsonian Institution make no claims as to the accuracy or completeness of this work.

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