Chronology of
Personal Computer Software

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This document is an attempt to bring various published sources together to present a timeline about Personal Computer Software.

References are numbered in [brackets], which are listed here. A number after the dot gives the page in the source.

Last updated: 2022 April 29.


  • Gary Kildall implements the PL/I programming language for the Intel 4004 processor. [266.xiv]


  • Gary Kildall creates the PL/M programming language for the Intel 8008, based on PL/I. [266.137]
  • Gary Kildall writes a simple operating system in his PL/M language. He calls it CP/M (Control Program/Monitor). [266.138] (Control Program for Microcomputer [346.50]) (Control Program / Microprocessor [1076.18]) (1974 [443.433] [1298.187])


  • Gary Kildall, of Microcomputer Applications Associates, develops the CP/M operating system for Intel 8080-based systems. [9] [176.64] [258.224]
  • Bravo is developed for the Xerox Alto computer. It is the first WYSIWYG program for a personal computer. [477.158]
(month unknown)
  • Gary Kildall and John Torode begin selling the CP/M disk operating system for microcomputers. [266.xv] [1149.175]


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]
  • At Harvard, Monte Davidoff helps Bill Gates and Paul Allen write the floating-point routines for their 8080 BASIC. [1149.78]
  • 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]
  • 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]
  • 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])
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]
  • 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]
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  • Bill Gates writes an open letter to microcomputer hobbyists, complaining about software piracy, to be published in an Altair newsletter. [346.30]


  • Ric Weiland completes writing 6800 BASIC for Micro-Soft. [1299.88]
(month unknown)
  • Micro-Soft licenses 6800 BASIC to MITS for a flat fee of US$31,200, to be paid US$1300 per month over two years. [1299.95]
February 3
  • David Bunnell publishes in his "Computer Notes" Altair newsletter an article from Bill Gates, complaining of software piracy. [346.30] [389.28] [1149.102] [1299.91]
  • Bill Gates writes software routines for BASIC on the Altair to use diskettes for storage. [346.28] (January [1299.90])
(month unknown)
  • Bill Gates offers to sell all rights and ownership of his 8080 BASIC to Ed Roberts and MITS for about US$6500. Roberts declines the offer. [1149.102]
  • David Bunnell's Computer Notes Altair newsletter publishes Bill Gates' "A Second and Final Letter" article on software piracy. [346.32] [1149.106]
  • Digital Research copyrights the CP/M operating system. [41]
(month unknown)
  • Microsoft licences 8080 BASIC to General Electric, for US$50,000. Half of the fee is paid to MITS. [1299.101]
  • Gary Kildall grants a license to CP/M to GNAT Computers for US$90. [346.51]
  • Michael Shrayer completes writing the Electric Pencil word-processing program for microcomputers. [9] [266.148] [346.258] [662.33] (1975 [1112.144])


  • Bill Gates and Paul Allen sign a partnership agreement to officially create the Microsoft company. Gates owns 64 percent, Allen owns 36 percent. [123] [1299.103] [1526.83]
  • Microsoft announces FORTRAN-80 language compiler. Price is US$500. [1299.110]
April 20
  • Bill Gates and Paul Allen write to MITS complaining of overdue royalty payments on 8080 BASIC, and of MITS' failure to sub-license and promote the product to others. They state that if the situation is not remedied within ten days, the licensing agreement for 8080 BASIC would be terminated. [1149.114] [1299.109]
April 21
  • An attorney for MITS denies Microsoft's charges, claiming MITS is up-to-date on royalty payments, and did not have to license 8080 BASIC to competitors. [1299.109]
  • An attorney for MITS pays Microsoft US$14,526 to cover 8080 BASIC royalty payments since December 1, 1976. [1299.109]
(month unknown)
  • MITS files for arbitration to seek a decision on whether its 8080 BASIC contract with Microsoft is still valid. [1299.109]
May 5
  • MITS files for a restraining order against Microsoft, to prevent Microsoft from licensing 8080 BASIC until the dispute with MITS is resolved. [1149.114] [1299.109]
May 12
  • A judge grants MITS' restraining order against Microsoft licensing 8080 BASIC, until July 8 or until the arbiter's determination is made. [1299.109]
(month unknown)
  • Gary Kildall grants a distribution license for CP/M to Seymour Rubenstein of IMSAI Manufacturing, for US$25,000. [346.51] [266.139] [1149.175]
  • Microsoft ships "Microsoft FORTRAN" for CP/M-based computers. [123] [346.49]
  • Microsoft licenses its 6502 BASIC to Apple Computer for US$21,000. [346.48] [1299.111] [2605.13] [2605.13] (early 1978 [949.300])
  • Apple Computer releases Applesoft, a version of BASIC with floating-point capabilities. It is licensed from Microsoft. [218]
  • Microsoft wins an important legal battle against Pertec, on ownership of the BASIC software Bill Gates and Paul Allen wrote and licensed to MITS. [346.45] (September [1299.111])


  • Ward Christianson and Randy Seuss begin building the Computerized Bulletin Board System, in Chicago, Illinois. [229.150]
(month unknown)
  • Microsoft sells a license for its BASIC 2.0 to Tandy Corporation for the TRS-80 Model 1 computer. [949.300]
  • Dan Bricklin has an idea for a microcomputer-based spreadsheet program. (The result will be VisiCalc.) [346.101] [1056.327]
  • Dan Bricklin completes a BASIC program demonstrating his proposed spreadsheet application. [618.67]
  • Microsoft ships Microsoft COBOL. [346.259]
(month unknown)
  • The G2 computer software stores of the Great Records and Tapes company begins selling TRS-80 Level III BASIC. The product is Microsoft's first retail software venture. [1299.125]
  • MicroPro International introduces WordMaster. [346.259]
(month unknown)
  • Bob Frankston, Dan Bricklin, and Dan Fylstra sign a contract to start Software Arts, and produce an electronic spreadsheet program. [266.230] [1056.327]
  • Personal Software company software publisher Dan Fylstra loans an Apple II to Dan Bricklin to create his spreadsheet program (will be VisiCalc). [618.67]
  • Automated Simulations sells its first copy of its first game, Starfleet Orion for the Commodore PET. The program was written by Jim Connelley and Jon Freeman. (The company name is later changed to Epyx.) [1532.10]
  • Microsoft records its first US$1 million sales year. [123] [1299.128]


January 2
  • Software Arts is incorporated. [1056.327] [1149.146]
  • Personal Software's Daniel Fylstra shows Apple Computer's Mike Markkula and Steve Jobs a prototype Applesoft program called Calculedger (later released as VisiCalc), written by Daniel Bricklin and Robert Frankston. Fylstra offers the program to Apple for $1 million. No deal. [2605.14]
(month unknown)
  • Microsoft decides to create an implementation of the BASIC programming language for the 8086 chip. Bob O'Rear is assigned the job. [1149.142] (fall 1978 [346.62])
  • Apple Computer releases DOS 3.2. [218]
April 4
  • The International Computer Programs awards Microsoft the Million Dollar Award for its 8080 BASIC. This is Microsoft's first corporate recognition from the industry, and the first microprocessor product to win this award. [123] [1299.130]
  • Bob Frankston, Dan Bricklin, and Dan Fylstra sign a contract for Software Arts to continue development of Visicalc, and for Personal Software to market the software. [1340.S3.12]
(month unknown)
  • Microsoft completes initial work on BASIC for the Intel 8086 processor. The simulated BASIC is running on a DEC 20, but an 8086-based computer is not available for testing the software. [346.62] [1149.143]
  • Software Arts demonstrates the VisiCalc spreadsheet software at the 4th West Coast Computer Faire in San Francisco, California. Dan Bricklin and Bob Frankston wrote it during 1978-79, under the company name Software Arts, under contract to Personal Software. [9.202] [80.126] [176.64] [203.9] [218] [266.xv] [346.102] [1299.132] [1886.64] [2605.14] (June [41] [1149.145])
  • Microsoft tries out its 8086 BASIC on Seattle Computer Products' 8086 processor card for the first time. By the end of the month, the 8086 BASIC is complete and working. [346.63] [1149.143]
  • MicroPro International releases the WordStar word processor, written by Rob Barnaby. It is made available for Intel 8080A and Zilog Z-80 based CP/M systems. [266.153] [346.259] [862.202] [1033.171] [1149.146] (written by Seymour Rubenstein [176.64])
  • At the National Computer Conference, Lifeboat Associates shares its 10ft x 10ft booth with Microsoft and Seattle Computer Products. Microsoft announces Microsoft BASIC 8086 running it on the 8086 card of Seattle Computer Products. [123] [346.63,259] [389.28] [1149.144] [1299.135]
(month unknown)
  • Apple Computer releases the word processing program AppleWriter 1.0. [218]
  • Apple Computer releases Apple Pascal. [912.136]
  • Automated Simulations releases the Temple of Apshai game for microcomputers. [809.20]
  • The Avalon Hill Game Company forms its Microcomputer Games Division, and releases games B-1 Nuclear Bomber, North Atlantic Convoy Raider, Nukewar, and Planet Miners. [1532.10]
  • Richard Garriott releases the Akalabeth game for the Apple II computer in the US. [1688.116]
  • Microsoft releases the Flight Simulator game for the Apple II. [1732.90]
  • MT MicroSystems releases the Pascal/MT language compiler for CP/M. Price is US$50. It features direct to machine code compilation, support for burning code into ROM chips, I/O port access, and in-line assembly code. (Over its lifetime, over 100,000 copies are sold of all versions (MT, MT+, MT+86).) [1167]
  • Apple Computer releases DOS 3.2.1. [218]
  • CompuServe begins a service to computer hobbyists called MicroNET, offering bulletin boards, databases, and games. [218]
  • Microsoft releases its Assembler language for 8080/Z80 microprocessors. [346.260]
  • Wayne Ratliff develops the Vulcan database program. (Ashton-Tate later markets it as dBase II.) [9] [346.259]
(month unknown)
  • Xerox and Microsoft sign a contract for Microsoft to supply a version of Stand-alone Disk BASIC for a Xerox - Convergent Technologies personal computer, Project Surf. The deal is worth US$150,000, about double to Microsoft's previous largest contract. [1149.150]
  • Microsoft begins developing an 8086 version of FORTRAN. [346.72]
October 17
  • Personal Software releases VisiCalc for the Apple II, for US$99. (Over its lifetime, over 700,000 copies are sold.) [46] [140] [218] [266.230] [346.102] [618.70] [1033.171] [1056.327] [1112.139] [1149.146] [2605.14] (November [120])
  • Seattle Computer Products begins shipping its 8086 CPU boards. Stand-alone BASIC from Microsoft is offered an an option. [1149.183]
(month unknown)
  • Digital Research begins packaging Gordon Eubanks' CBASIC with CP/M. [1149.177]
  • Apple Computer's Trip Hawkins negotiates a deal with Dan Fylstra of Personal Software to buy his company and VisiCalc for US$1 million in Apple Computer stock. Apple's president refuses to approve the deal. [618.72]
  • Atari contracts with MT MicroSYSTEMS to create a 6502 Pascal compiler to support both P-Code and native code for Atari 800 and 400. [1167]
  • Microsoft Consumer Products releases its first products: TRS-80 Level III BASIC, Typing Tutor, and Adventure. The Adventure game was written by Gordon Letwin, the only Microsoft employee to be paid royalties for a product written off company time. [1299.133]

End of 1972-1979. Next: 1980.
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1972-1979 1980-1981 1982 1983 1984 1985 1986 1987 1988 1989
1990 1991 1992-1993 1994-1995 1996-1997 1998-1999 2000-2001 2002-2003 2004 2005

A list of references to all source material is available.

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