--- title: KENBAK COMPUTER COMPANY Kenbak-1 categories: - Computers types: - Home Computer origins: - U.S.A. years: - '1971' cpus: - None - TTL based logic params: name: Kenbak-1 image: /media/museum/photos/kenback1_1s.jpg company: /companies/kenbak-computer-company company_name: KENBAK COMPUTER COMPANY specs: - label: NAME value: Kenbak-1 - label: MANUFACTURER value: Kenbak Computer Company - label: TYPE value: Home Computer - label: ORIGIN value: U.S.A. - label: YEAR value: '1971' - label: END OF PRODUCTION value: '1973' - label: BUILT IN LANGUAGE value: None - label: KEYBOARD value: Front panel keys only - label: CPU value: None - TTL based logic - label: SPEED value: approx 1 MHz - label: RAM value: 256 bytes of shift-register memory - label: TEXT MODES value: None - label: GRAPHIC MODES value: None - label: COLORS value: None - label: SOUND value: None - label: SIZE / WEIGHT value: '18' - label: I/O PORTS value: None - label: POWER SUPPLY value: Linear - label: PRICE value: $750 new tabs: - photos - adverts - links - docs forum_thread: 1226 photos: - title: KENBAK-1 subtitle: '' text: Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture image: /media/museum/photos/kenback1_1.jpg - title: RUNNING SYSTEM subtitle: '' text: Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture image: /media/museum/photos/kenback1_running.jpg - title: INSIDE subtitle: '' text: Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture image: /media/museum/photos/kenback1_inside.jpg adverts: - title: ADVERT subtitle: '' text: |- John V. Blankenbaker designed the Kenbak-1 and marketed in the pages of Scientific American in 1971. The machine's name was taken from the middle of John's last name. Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture image: /media/museum/pubs/kenback1_1_pub.jpg links: - title: Computer Museum of Nova Scotia url: http://www.computermuseum.20m.com/kenbak.htm text: They have a collection of seven Kenbak-1 computers! Good pictures. - title: www.kenbak-1.net url: http://www.kenbak-1.net/ text: Official website by Kenbak creator John Blankenbaker himself! - title: www.thefirstpc.com url: https://www.thefirstpc.com/ text: The only Kenbak-1 prototype - title: www.vintage-computer.com url: http://www.vintage-computer.com/kenbak-1.shtml text: Nice dedicated page with nice pictures and interesting info docs: - title: PROGRAMMING REFERENCE MANUAL url: http://www.kenbak-1.net/index_files/page0008.htm cover: /media/museum/docs/couvs/kenbak_doc_prm.jpg text: |- [**PROGRAMMING REFERENCE MANUAL**](http://www.kenbak-1.net/index_files/page0008.htm)written by Kenbak  compiled/archived by John Blankenbaker\  type of document : PDF\  size : 1,3 MB\  source : [www.kenbak-1.net](http://www.kenbak-1.net) - title: INSTALLATION, MAINTENANCE AND THEORY OF OPERATION url: http://www.kenbak-1.net/index_files/page0008.htm cover: /media/museum/docs/couvs/kenbak_doc_theory.jpg text: |- [**INSTALLATION, MAINTENANCE AND THEORY OF OPERATION**](http://www.kenbak-1.net/index_files/page0008.htm)written by Kenbak  compiled/archived by John Blankenbaker\  type of document : PDF\  size : 2,2 MB\  source : [www.kenbak-1.net](http://www.kenbak-1.net) - title: LABORATORY EXERCISES url: http://www.kenbak-1.net/index_files/page0008.htm cover: /media/museum/docs/couvs/kenbak_doc_exercise.jpg text: |- [**LABORATORY EXERCISES**](http://www.kenbak-1.net/index_files/page0008.htm)written by Kenbak  compiled/archived by John Blankenbaker\  type of document : PDF\  size : 2,3 MB\  source : [www.kenbak-1.net](http://www.kenbak-1.net) - title: OFFICIAL BROCHURE url: http://bitsavers.org/pdf/kenbak/ cover: /media/museum/docs/couvs/kenbak_doc_brochure.jpg text: |- [**OFFICIAL BROCHURE**](http://bitsavers.org/pdf/kenbak/)written by Kenbak  type of document : PDF\  size : 817 KB\  source : [bitsavers.org](http://bitsavers.org) oc_id: 1259 source: url: https://web.archive.org/web/20230607133943/http://www.old-computers.com/museum/computer.asp?c=1259 date: '2023-06-07' --- The Kenbak-1 is considered by many to be the world's first "Personal Computer." The Computer History Museum granted it this designation when they were still located in Boston in 1986. More specifically, the machine represents the first commercially available Von Neumann (stored program) computing device intended and priced for personal use. John V. Blankenbaker designed the Kenbak-1 and marketed in the pages of Scientific American in 1971. The machine's name was taken from the middle of John's last name. The Kenbak-1 was designed in 1970 and pre-dated microprocessors. The Intel 4004 (the worlds first microprocessor) was introduced in 1971. Instead of being microprocessor based the Kenbak-1 was built almost entirely from TTL components. Unlike many earlier machines and calculating engines, the Kenbak-1 was a true stored-program computer that offered 256 bytes of memory, a wide variety of operations and a speed equivalent to nearly 1MHz. Approximately 40 of these machines were built and sold before they were discontinued. The world just wasn't quite ready for personal computing and the Kenbak-1 lacked some critical capabilities (such as expandability and I/O) that were needed to foster the revolution. 14 are currently known to exist with few more likely to be discovered. --- **Contributors**: Erik Klein **Julian Skidmore** (Manchester, UK) comments:\ Although the Kenbak-1's oscillator is 1MHz, it's clock speed was half that at 500KHz and simple calculations show it must execute instructions at an astonishingly low rate 300 instructions per second or less. This is because: 1\. Memory is 1024 bits of serial memory, so random access will take 512 cycles on average - 1000 access per second. 2\. CPU registers are placed in main memory too, and a typical instruction involves reading/writing the program counter, the accumulator and the instruction itself. Thus a maximum 1000/3 = 333 instructions can execute per second. Having said that, the architecture is impressive. It looks like a typical 8-bit CPU: with several registers, multiple addressing modes including indexed addressing and variable length instructions.