Chronology of Personal Computers (1975)



January 1

  • Bill Gates signs a document formalizing the existence of the Traf-O-Data company. Owners of assets are: Bill Gates 43%, Paul Allen 36%, and Paul Gilbert 21%. This step was necessary for Gates and Allen to use Traf-O-Data’s 8008 simulator to develop BASIC for the Altair. [1299.69]
January 2

  • Bill Gates and Paul Allen write to MITS, saying they have a BASIC language for the Intel 8080 processor. They propose licensing it for use on the Altair in exchange for royalty payments. (They then spend the next eight weeks writing the software.) [1149.74] [1299.70]

  • Bill Gates begins writing BASIC for the Altair, basing it on Digital Equipment’s RSTS-11 BASIC-PLUS. [1299.71]
  • Harry Garland and Roger Melen receive Altair number 0002. They had proposed in December to attach their Cyclops camera to the Altair, for use as a security camera. [266.38]
  • At Harvard, Monte Davidoff helps Bill Gates and Paul Allen write the floating-point routines for their 8080 BASIC. [1149.78]
(month unknown)

  • Ed Roberts coins the term “personal computer” as part of an advertising campaign for the Altair. [1149.72]

  • The Xerox PARC-developed Gypsy word-processing system is first field-tested by end-users. Gypsy is one of the first word processors termed “WYSIWYG”, meaning what you see is what you get. Gypsy runs on the PARC-developed Alto personal computer. [716.111]
  • Paul Allen flies from Harvard to Albuquerque, New Mexico, to meet with Ed Roberts at MITS, to demonstrate the newly written BASIC interpreter for the Altair. Allen writes a paper tape reader on the plane trip, for the Altair to load the BASIC software. [346.24,257] [1149.80] [1299.74]
  • At MITS, Paul Allen enters the paper tape loader on an Altair with 7 kB RAM, the Altair reads the paper tape, and it is ready to execute BASIC instructions. Allen types “PRINT 2 + 2”, and the Altair responds “4”. Despite Gates and Allen never having touched an Altair before, their BASIC works flawlessly. Paul then types in the BASIC source code for a Lunar Lander game from a book. This becomes the first software program ever run on what would later become Microsoft BASIC. [346.24,257] [606.17] [1149.80] [1299.74]
  • Bill Gates and Paul Allen license their newly written BASIC to MITS, their first customer. MITS will pay a small royalty with a ceiling of US$180,000. This is the first computer language program written for a personal computer. [123] [176.122] [389.28] [1701.158]
March 5

  • Fred Moore and Gordon French hold the first meeting of a new microcomputer hobbyist’s club in French’s garage, in Menlo Park, California. 32 people meet, including Bob Albrect, Steve Dompier, Lee Felsenstein, Bob Marsh, Tom Pittman, Marty Spergel, Alan Baum, and Steven Wozniak. Bob Albrect shows off an Altair, and Steve Dompier reports on MITS, and how they had 4000 orders for the Altair. (After a few meetings, the club is given the nickname “Homebrew Computer Club”.) [185.110] [266.104] [301.55] [346.18] [353.200] [346.257] [930.31] [1149.98] [1298.187] [1299.80] [2322] [2605.4] (April [208.67] [266.39])

  • Ed Roberts hires Paul Allen as Vice President and Director of Software at MITS. [266.40] [1149.83] [1299.76] (May [346.25])
(month unknown)

  • The second meeting of Fred Moore/Gordon French’s computer hobbyists group is held at the Stanford AI lab. 40 attend. The name for the group is chosen: Bay Area Amateur Computer Users Group – Homebrew Computer Club. [353.203]

  • At MITS, David Bunnell starts the Computer Notes newsletter. [1149.92] [1299.77]
  • The third meeting of the Homebrew Computer Club is held. [353.208]
  • The fourth meeting of the Homebrew Computer Club is held at the Peninsula School in Menlo Park. Steve Dompier plays parts of the music “Fool on the Hill” and “Daisy” using the Altair and a radio. [346.20] [353.203] [1299.80]
  • Bill Gates and Paul Allen found Micro-Soft (the hyphen is later dropped). [41] [1149.90] [1280.42] [1298.187] [1526.82] (July [346.26]) (August [346.257]) (September 23 [2241.64])
  • MITS delivers the first generally-available Altair 8800, sold for US$375 with 1 kB memory. [208.67] (256 bytes [266.38])
  • Bob Marsh and Gary Ingram found Processor Technology. [266.45] [353.208]

  • The Amateur Computer Group of New Jersey is formed. [208.67] [266.xv]

  • MOS Technology announces the MC6501 processor for US$20 and the MC6502 for US$25. [9] [261.304] (Fall [824])
  • Bob Marsh delivers the first Processor Technology 4 kB memory boards for the Altair. [266.110] [353.210]
  • The Southern California Computer Society is formed. [266.184]
  • At Xerox, John Ellenby proposes they build the Alto II personal computer, a modified Alto, making it easier to produce, more reliable, and more easily maintained. His request is approved. [716.205]
  • Paul Terrell signs a deal with MITS in which Terrell would receive a 5 percent commission on every Altair sold in Northern California, for promoting and selling the Altair. [266.188]
(month unknown)

  • Motorola sues MOS Technology over the similarity of the 6501 and 6502 processors to the 6800. (In an out-of-court settlement, MOS Technology withdraws the 6501 from the market.) [824]
  • At IMS Associates, Joseph Killian begins designing the first Altair-compatible microcomputer. [266.63] [1702.11]
  • Hard drive maker Tandon is formed. [971.F9]
  • Gordon Moore revises his 1965 prediction about transistor density, from doubling every 12 months to doubling every 18 months. This is known as Moore’s Law. [1000.20] (every 24 months [1559])
  • Intel develops the Multibus 8-bit memory bus structure. [999.77]
  • Wavemate releases the Jupiter II computer kit. [218]
  • Southwest Technical Products releases the M6800 computer kit. [218] [208.67]
  • Microcomputer Associates releases the JOLT computer kit. [218]
  • In the USSR, the Elektronika S5-01 personal computer is introduced. The microprocessor is the K586 NMOS chip series. [949.356]
  • MITS begins work on a Motorola 6800-based Altair. [266.47]
  • MITS sales of Altair computers hits US$1 million. [346.31]
  • Sphere Corporation introduces its Sphere I computer kit, featuring a Motorola 6800 CPU, 4 kB RAM, ROM monitor, keyboard, and video interface, for US$650. [9.200] [16.371]
  • Harry Garland and Roger Melen found Cromemco. The company is named after the Crowthers Memorial dorm at Stanford. [266.xv] [353.207]
  • Digital Equipment introduces the LSI-11 microcomputer (board with microprocessor), with 8 kB RAM. It is the first American microcomputer using a 16-bit architecture. [949.358]
  • IBM’s John Cocke begins work on project “801”, to develop a scaleable chip design that could be used in small computers as well as large. [205.103]
  • Wayne Green founds BYTE Magazine. [713.219]
  • A patent on Ethernet computer networking is applied for by David Boggs, Butler Lampson, Bob Metcalfe, and Charles Thacker of Xerox PARC. [1298.187]

  • Dick Heiser opens Arrow Head Computer Company, subtitled “The Computer Store”, in Los Angeles, selling assembled Altair computers, boards, peripherals, and magazines. This is the first independent retail computer store in the USA. [266.185] [684.41] [1299.85]
July 22

  • Bill Gates and Paul Allen sign a licensing agreement with MITS, for their implementation of the BASIC language. Gates and Allen receive US$3,000 immediately, with royalties of US$30 per copy of 4K BASIC, and US$35 for 8K BASIC. [299.8] [1149.92] [1299.82]

  • Bill Gates and Paul Allen ship 4K and 8K versions of BASIC v2.0 to MITS. [123] [1149.92] [1299.83]
(month unknown)

  • IMS Associates announces the IMSAI 8080 microcomputer. [346.32] [647.95]

  • IBM’s Entry Level Systems unit unveils the IBM 5100 Portable Computer. It is a briefcase-size minicomputer with BASIC, 16 kB RAM expandable to 64 kB, tape storage drive holding 204 kB per tape, keyboard, and built-in 5-inch screen. Price: US$8975-19975. Weight: 55 pounds. Code-name during development was Project Mercury. [9] [197.xi] [606.22] [902.137] [1112.144] [1310] (Price over US$10,000 [203.10])
  • The first issue of BYTE magazine is published. [9] [266.159]

  • The October issue of MITS’ Computer Notes newsletter announces availability of BASIC 2.0 from Micro Soft for the Altair 8800, in 4K and 8K editions. (This is the earliest known reference to “Micro Soft”.) [9] [123] [208.67] [346.257] [1299.86]
  • The October issue of MITS’ Computer Notes newsletter announces a new Altair 680 based on the Motorola 6800 processor. Price is US$293 as an unassembled kit. [1299.86]

  • In Kansas City, the first standards conference of the microcomputer industry is held. A single standard is agreed to for storing data on audio cassette tapes. [1299.89]
(month unknown)

  • MITS decides to release a floppy disk storage system for the Altair computer. [1149.98]
December 8

  • Paul Jay Terrell opens the Byte Shop, in Mountain View, California, one of the first computer stores in the United States. [34] [266.189] [2605.7]

  • Bill Gates writes an open letter to microcomputer hobbyists, complaining about software piracy, to be published in an Altair newsletter. [346.30]
  • IMS Associates hires Ed Faber as Director of Sales. [266.193] (1976 January [266.64])
  • Lee Felsenstein and Bob Marsh begin work on a complete computer, 8080-based with a keyboard and color video display capabilities built-in. [353.240]
December 16

  • IMS Associates begins ships its first IMSAI 8080 computer kits to customers. [1702.18]
December 31

  • To date, MITS has sold 2,000 Altair 8800 systems. IMS Associates has shipped 50 IMSAI 8080 systems. [176.54] [1702.18] (5,000 [1298.187])


End of 1975. Next: 1976.

1947-1968 1969-1971 1972-1974 1975 1976 1977 1978 1979 1980 1981
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