Kenbak-1

The Kenbak-1 is considered by the Computer History Museum and the American Computer Museum[1] to be the world's first "personal computer",[2] invented by John V. Blankenbaker (1930-) of Kenbak Corporation in 1970, and first sold in early 1971.[3] Only 50 machines were ever built using Bud Industries enclosures as its housing per the Oral History of John Blankenbaker. The system first sold for US$750.[4] Today only 14 machines are believed to exist worldwide,[5] in the hands of various collectors. Production of the Kenbak-1 stopped in 1973[6] as Kenbak failed, and was taken over by CTI Education Products, Inc. CTI rebranded the inventory and renamed it the H5050, though sales remained elusive.[7]

Kenbak-1
A Kenbak-1 at the Computer History Museum
DeveloperJohn Blankenbaker
ManufacturerKenbak Corporation
Typepersonal computer
Release date1971 (1971)
Introductory priceUS$750 (equivalent to $4,735 in 2019)
Discontinued1973 (1973)
Units sold40
Units shipped40
Memory256 bytes of memory

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 small-scale integration TTL chips.[8] The 8-bit machine offered 256 bytes of memory,[9] implemented on Intel's type 1404 silicon gate MOS shift registers.[10] The instruction cycle time was 1 microsecond (equivalent to an instruction clock speed of 1 MHz), but actual execution speed averaged below 1000 instructions per second due to architectural constraints such as slow access to serial memory.[8]

The machine was programmed in pure machine code using an array of buttons and switches. Output consisted of a row of lights.

Internally, the Kenbak-1 has a serial computer architecture, processing one bit at a time.[11][12]

See also
  • Datapoint 2200, a contemporary machine with alphanumeric screen and keyboard, suitable to run non-trivial application programs.
  • Mark-8 The Mark-8 was designed by graduate student Jonathan A. Titus and announced as a 'loose kit' in the July 1974 issue of Radio-Electronics magazine.
  • Altair 8800, a very popular 1975 microcomputer that provided the inspiration for starting Microsoft.

References
  1. "The George R. Stibitz Computer Pioneer Award". Archived from the original on September 13, 2008. Retrieved August 5, 2008.
  2. "Timeline of Computer History". Computer History Museum. Retrieved July 22, 2008.
  3. BBC News, November 6, 2015
  4. "Kenbak-1 The Training Computer". Computerworld. November 17, 1971. p. 43. Retrieved May 25, 2014.
  5. "Kenbak-1". Computer Museum of Nova Scotia. Retrieved 19 November 2015.
  6. p. 52, "The First Personal Computer", Popular Mechanics, January 2000.
  7. Robert R Nielsen, Snr (2005). "Inside the Kenbak-1". Retrieved 8 November 2015.
  8. Erik Klein. "Kenbak Computer Company Kenbak-1". Old-computers.com. Retrieved May 25, 2014.
  9. Bill Wilson (6 November 2015). "The man who made 'the world's first personal computer'". BBC News.
  10. "Technical".
  11. "Kenbak Theory of Operation Manual". p. 16.
  12. "Official Kenbak-1 Reproduction Kit".
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