Intel C4004 Grey Trace

In 1969 Intel were approached by a Japanese company called Busicom to produce chips for Busicom's electronic desktop calculator. Intel suggested that the calculator should be built around a single-chip generalized computing engine and thus was born the first microprocessor - the 4004. Although it was based on ideas from much larger mainframe and mini-computers the 4004 was cut down to fit onto a 16-pin chip, the largest that was available at the time, so that its data bus and address bus were each only 4-bits wide.

Back then the 4004 operated at a mighty 740KHz — and at roughly eight clock cycles per instruction cycle (fetch, decode, execute), that means the chip was capable of executing up to 92,600 instructions per second. The 4004 used state-of-the-art Silicon Gate Technology (SGT) PMOS logic — a technique that Faggin perfected at Fairchild Semiconductor in 1968 — the world’s first metal-oxide-silicon (MOS) process. This breakthrough allowed the 4004 to have no less than 2,300 transistors and a feature size of 10 micron. Considering a human hair is around 100 micron, the 4004 was still rather impressive — but irrespective of feature size or transistor count, the fact that it was carved from a single piece of silicon is what made the 4004 truly spectacular. Faggin was so proud of his creation that he even signed the chip “FF”, which you can see in the top right of the image below.

Despite the 4004’s success — and the popularity of its 8-bit successors, 8008 and 8080 — Intel was still very much a DRAM and SRAM company at the time. It wasn’t until the late ’70s with the 8088, which powered the IBM PC and its clones, that Intel decided to make the shift towards microprocessors, and as we now know, the rest is history.

The 4004 family is also referred to as the MCS-4.


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