Intel 8008
The Intel 8008 was Intel's first 8-bit microprocessor, introduced in April 1972, and it matters as the architectural bridge between the 4-bit 4004 and the processors that would actually launch personal computing. Where the 4004 had been conceived for a calculator, the 8008 was built to a different customer's specification entirely: it originated as a terminal processor, which is why its instruction set and register structure look more like a general-purpose computer than like calculator arithmetic logic. It ran at clock rates around 500–800 kHz depending on the version and addressed up to 16 KB of memory, modest numbers whose significance is that they were enough to run real general-purpose programs.
The 8008 began as a contract for Computer Terminal Corporation's Datapoint 2200 programmable terminal, and the way that project went sideways shaped the whole early industry. CTC specified the processor architecture it wanted for the Datapoint 2200; Intel agreed to implement it as a single chip. By the time the chip was ready it was late and CTC had already built the terminal using conventional discrete TTL logic, so CTC declined the part and, in lieu of payment, let Intel keep the design and the rights to sell it. Intel brought it to market as the 8008 — meaning the architecture of Intel's first 8-bit processor was effectively designed by a terminal maker, and the x86 register and instruction conventions that still echo in modern PCs trace part of their ancestry to that terminal specification.
The jump from 4 bits to 8 bits is not a doubling of a number but a change in what the processor can comfortably represent, which is why the 8008 opened doors the 4004 could not. An 8-bit word holds a full byte, enough to encode a character of text directly, so a processor that manipulates bytes natively is suited to handling text, terminal data, and general symbolic work rather than just packed numeric digits. This is the practical reason the lineage of general-purpose computing runs through the 8-bit parts: once the native unit of work was the byte, the processor stopped being a specialized calculator engine and became a plausible core for computers that handle arbitrary data.
The 8008 was powerful in principle but awkward in practice, and its shortcomings are what motivated its far more successful successor. It required a substantial number of support chips to build a working system, used a multiplexed scheme that complicated the surrounding circuitry, and was slow enough that many intended applications strained against its limits. Intel engineer Federico Faggin and his colleagues addressed these problems directly in the 8080 of 1974, which kept software compatibility close enough to inherit the 8008's ecosystem while being substantially faster and far easier to design around — so the 8008 functioned as the rough draft whose lessons produced the processor that actually took off.
The 8008's legacy is architectural continuity rather than commercial dominance. It was never the chip at the center of a hit product the way the later 8080, 6502, and Z80 were, but it established the 8-bit, byte-oriented, general-purpose direction that those parts refined, and its instruction-set DNA carried forward through the 8080 into the 8086 and the x86 family. Studying the 8008 is therefore less about what was built with it and more about seeing where a durable set of architectural conventions entered the world — through a declined terminal contract that Intel turned into a product line.
Read the Intel 8008 as the draft that set the direction: an 8-bit terminal processor Intel inherited rather than planned, whose byte-oriented, general-purpose design pointed the microprocessor away from calculators and toward the computers its successors would actually become.