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yann64andClaude Opus 5.5 b274874139 All machines linked to their forum thread (full comment import)
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title, categories, types, origins, years, cpus, params
title categories types origins years cpus params
KENBAK COMPUTER COMPANY Kenbak-1
Computers
Home Computer
U.S.A.
1971
None - TTL based logic
name image company company_name specs tabs forum_thread photos adverts links docs oc_id source
Kenbak-1 /media/museum/photos/kenback1_1s.jpg /companies/kenbak-computer-company KENBAK COMPUTER COMPANY
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NAME Kenbak-1
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MANUFACTURER Kenbak Computer Company
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TYPE Home Computer
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ORIGIN U.S.A.
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YEAR 1971
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END OF PRODUCTION 1973
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BUILT IN LANGUAGE None
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KEYBOARD Front panel keys only
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CPU None - TTL based logic
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SPEED approx 1 MHz
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RAM 256 bytes of shift-register memory
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TEXT MODES None
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GRAPHIC MODES None
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COLORS None
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SOUND None
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SIZE / WEIGHT 18
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I/O PORTS None
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POWER SUPPLY Linear
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PRICE $750 new
photos
adverts
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docs
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KENBAK-1 Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture /media/museum/photos/kenback1_1.jpg
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RUNNING SYSTEM Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture /media/museum/photos/kenback1_running.jpg
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INSIDE Thanks to [www.vintage-computer.com](http://www.vintage-computer.com) for this picture /media/museum/photos/kenback1_inside.jpg
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ADVERT 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 /media/museum/pubs/kenback1_1_pub.jpg
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Computer Museum of Nova Scotia http://www.computermuseum.20m.com/kenbak.htm They have a collection of seven Kenbak-1 computers! Good pictures.
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www.kenbak-1.net http://www.kenbak-1.net/ Official website by Kenbak creator John Blankenbaker himself!
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www.thefirstpc.com https://www.thefirstpc.com/ The only Kenbak-1 prototype
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www.vintage-computer.com http://www.vintage-computer.com/kenbak-1.shtml Nice dedicated page with nice pictures and interesting info
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PROGRAMMING REFERENCE MANUAL http://www.kenbak-1.net/index_files/page0008.htm /media/museum/docs/couvs/kenbak_doc_prm.jpg [**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)
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INSTALLATION, MAINTENANCE AND THEORY OF OPERATION http://www.kenbak-1.net/index_files/page0008.htm /media/museum/docs/couvs/kenbak_doc_theory.jpg [**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)
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LABORATORY EXERCISES http://www.kenbak-1.net/index_files/page0008.htm /media/museum/docs/couvs/kenbak_doc_exercise.jpg [**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)
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OFFICIAL BROCHURE http://bitsavers.org/pdf/kenbak/ /media/museum/docs/couvs/kenbak_doc_brochure.jpg [**OFFICIAL BROCHURE**](http://bitsavers.org/pdf/kenbak/)written by Kenbak  type of document : PDF\  size : 817 KB\  source : [bitsavers.org](http://bitsavers.org)
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url date
https://web.archive.org/web/20230607133943/http://www.old-computers.com/museum/computer.asp?c=1259 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.