One of only ten surviving Kenbak-1 personal computers from 1971 has sold at auction for €34,000 (US$36,500). Judged the "first commercially available personal computer" in 1987 by a panel at the Boston Computer Museum that included Apple co-founder Steve Wozniak, it's a fascinating piece of history that sheds a light on the chaotic early days of the desktop computer.

The Kenbak-1 was the brainchild of computer engineer John Blankenbaker, who in 1971 founded the short-lived Kenbak Corporation in Los Angeles to market an affordable computer for schools to provide students with hands-on experience in programming. The 14-lb (6.3-kg) computer was housed in a blue polygonal steel case, and because it was created before the introduction of microprocessors, its logic board (AKA motherboard) used small-scale-integration TTL chips on a printed circuit board and MOS shift registers for the serial memory.

The result was an 8-bit computer that had 256 bytes of memory and ran at below 1000 instructions per second. Programming was strictly machine code with 15 switches providing input and lights for output, similar to the Altair of the same era. It was originally supposed to sell for US$500, but by the time it was advertised in the September 1971 issue of Scientific American, the price had risen to US$750.

John Blankenbaker with the Kenbak-1(Credit: Auction Team Breker)

Unfortunately, the Kenbak-1 proved a commercial failure with only about 40 units produced between 1971 and 1973, of which only ten are estimated to still exist. According to Blankenbaker, it's failure was due to his marketing it to slow-deciding schools instead of the more enthusiastic hobbyist market.

As to whether the Kenbak-1 is indeed a contender for the first personal computer, it rather depends on how "personal computer" is defined. Too broad a definition, and it could include the extremely basic Simon computer from 1950. Too narrow, and even the first Apple Macintosh might have trouble claiming the prize. Usually, the criteria includes a combination of things like system architecture, whether the candidate is a standalone device, ready-built instead of a kit, simple enough for the non-computer expert, can do useful work, was commercially released, or adopted by the public or industry. Even so, this leaves a lot of room for debate – and it's a debate that will probably never be exhausted.

The Kenbak-I no. 0185 was auctioned buy Auction Team Breker on November 7 and is described in the catalog as having all-original parts and in functioning, though delicate, condition.

View gallery - 3 images