MrSeb writes: "Four decades ago today — November 15, 1971 — Intel placed an advertisement for the first single-chip CPU, the Intel 4004, in Electronic News. Designed by the fantastically-forenamed Federico Faggin, Ted Hoff, and Stanley Mazor, the 4004 was a 4-bit, 16-pin microprocessor that 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. Curiously, Intel actually created the chip for Busicom, a Japanese calculator manufacturer. Busicom actually owned the exclusive license for the 4004 — but eventually allowed to Intel to sell the 4004 commercially. As we know, the 8008 and 8080 followed, and then with the IBM PC the historic 8088. The rest is history."