The Intel 4004 was the world’s first microprocessor—a complete general-purpose CPU on a single chip. Released in March 1971, and using cutting-edge silicon-gate technology, the 4004 marked the beginning of Intel’s rise to global dominance in the processor industry. So you might imagine that the full resources of Intel—still a fledgling company at the time—were devoted to this groundbreaking project. But in fact, the 4004 was an understaffed side project, a crash job that nearly crashed, one simply intended to drum up some cash while Intel developed its real product line, memory chips.
As described by Ken Shirrif in a July 2016 feature for IEEE Spectrum, the increasing transistor count and complexity of integrated circuits in the 1960s meant that by 1970, multiple organizations were hot on the path to the microprocessor. Some of these, like Texas Instruments, had a lot more resources than Intel. So why did Intel, founded just a few years earlier, in 1968, cross the finish line first? It was largely thanks to four engineers, one of whom didn’t even work for the company. (For a lengthy version of this story from the engineers themselves, you can read their oral history panel, as captured by the Computer History Museum).
The first of the four engineers is Masatoshi Shima, who worked for Japanese office calculator company Busicom, which wanted to create a new computerized calculator. In April 1969, Busicom and Intel signed a provisional agreement for Intel to develop a custom set of chips for the calculator. Consequently, in June 1969 Shima and others traveled to Intel to discuss the plans in more detail. Shima proposed an eight-chip system: three chips to interface with peripherals such as the keyboard and printer, one chip to store data, one chip to store program code, and two chips that together would make up the CPU.
Read more: CHIP HALL OF FAME: INTEL 4004 MICROPROCESSOR
