Kenbak-1

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The Kenbak-1 is considered by the Computer History Museum to be the world's first ever "personal computer" (however, the Datapoint 2200 may have been invented first, sold first, or both; the exact dates have not been established). Very little is known about the Kenbak-1, as around only 40 machines were ever built and sold. It was designed and invented by John Blankenbaker of Kenbak Corporation in 1970, and was first sold in early 1971. The system first sold for US$750. In 1973, production of the Kenbak-1 stopped as Kenbak Corporation folded.

Since the Kenbak-1 was invented before the first microprocessor, the machine didn't have a one-chip CPU but instead was based purely on discrete TTL chips. The 8-bit machine offered 256 bytes of RAM (≈1/4000 megabyte). The instruction cycle time was 1 microsecond (equivalent to an instruction clock speed of 1 Mhz).

To use the machine, one had to program it with a series of buttons and switches, using pure machine code. Output consisted of a series of lights.