There was a considerable
time gap between the architectural proposal made by Ted Hoff and Stan Mazor to
Busicom, the Japanese calculator manufacturer who owned exclusive
rights to the 4000 family chip-set, and the beginning of the
implementation of the microprocessor. The proposal was idling for six months
without any progress, until Faggin was hired from Fairchild to lead the project in April 1970.
This gap defines two phases of separate activities: the first phase of
architectural definition, the second phase of design and development. There was
no interaction between Hoff, who by then was working on other projects, and
Faggin during the development phase. Soon after joining Intel, Faggin completed
some architectural issues left unresolved and designed the microprocessor
without any participation or help from Ted Hoff or Stan Mazor.
Faggin was expert in
Silicon Gate Technology, the technology that he had created at
Fairchild Semiconductor. He also knew computer architecture intimately having
co-designed and built one of the early small computers at Olivetti, in Italy,
before attending University, when he was 19 years old. This combined knowledge
provided a unique background for a most challenging job. In 1968, the basic
problem of the industry was not so much the identification of a viable computer
architecture, but being able to implement a high-performance chip with about
2500 transistors, within the capabilities of a very limited technology. Small
computers had been designed and built for years using small-scale and
medium-scale integration TTL circuits (for example, see 8008).
Faggin worked furiously for 11 months to implement the Busicom chip set.
He made all the decisions that can make or break a project and took the risk of a possible
failure. The rapid and successful implementation of the 4004 was also one of the
key factors that gave Intel the lead over other competing microprocessor
architectures being considered by other companies at that time. Contrary to many
reports in the press, Faggin and not Hoff was the leader of the