Chronology of
IBM Personal Computers

Copyright © 2006-2022
internet e-mail:
All rights reserved. Permission is granted to create web links
to this site, not to copy these pages to other web sites.

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

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.


  • A complaint is filed against IBM, alleging monopolistic practices in its computer business, in violation of the Sherman Act. (The government's antitrust investigations and trial against IBM will drag on for thirty years, finally being dismissed in 1982. IBM will cautiously monitor its microcomputer business practices, fearful of a repeat of government scrutiny.) [569.138] [1298.186]


  • A U.S. District Court makes a final judgement on the complaint against IBM filed in January 1952 regarding monopolistic practices. A "consent decree" is signed by IBM, placing limitations on how IBM conducts business with respect to "electronic data processing machines". (Though personal computers are twenty years in the future, this consent decree will limit IBM's success and ability to compete in the marketplace.) [569.138]
September 13
  • IBM introduces the IBM 350 Disk File, the first hard drive, as part of the IBM RAMAC 305 computer. The drive features fifty double-sided 24-inch diameter platters, served by one arm and one read/write head. Capacity is about 5 MB, and transfer rate is 8800 characters per second. (The first hard drives for personal computers will appear in about 15 years, also with a capacity of about 5 MB.) [609.89] [838.S2] [945.61] [1089.392] [1606.54] [1612.55] [2065.93] [2097.20] [2238.99] (November [798.152])


  • 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])


  • In Japan, IBM Japan announces the IBM 5100 desktop system, with 5-inch monochrome display. Price is about US$10,000. [902.146]
(month unknown)
  • An IBM senior staff planning exercise forecasts the personal systems market in the 1990s would be worth US$100 billion. [606.83]


  • In Japan, IBM Japan announces the IBM 5110 desktop system, like the IBM 5100 but supporting floppy drives, and with built-in BASIC. [902.146]


  • In Japan, IBM Japan announces the IBM 5120 desktop system, like the IBM 5110 but with a 9-inch screen. [902.146] [1310]
  • Bill Lowe, director of IBM's Boca Raton Labs, receives a proposal from Atari for IBM to market an Atari computer. [1299.150]
  • William Lowe suggests to an IBM Corporate Management Committee that IBM buy a computer from Atari to sell under the IBM name. He is told this is "the dumbest thing we've ever heard of", and is told to begin development of IBM's own personal computer. He is to assemble a team and bring back a prototype machine in 30 days. [606.23] [620.110] [716.237] [1149.167] [1299.150]
  • William Lowe assembles the members of "Project Chess", known as the "Dirty Dozen", the twelve engineers chosen to design and build a prototype personal computer, in Boca Raton, Florida. Don Estridge is project manager, Jack Sams heads the software effort. [618.126] [41] [902.254] [1299.150] (September [346.69])
July 21
  • Jack Sams of IBM's personal computer team first contacts Microsoft asking to talk about personal computers. [1149.168] [1299.151]
July 22
  • IBM representatives meet with Microsoft's Bill Gates and Steve Ballmer to talk about Microsoft products, and home computers. [266.271] [346.70] [1298.163] [1299.151]
August 8
  • The Project Chess task force at IBM shows a prototype microcomputer to the Corporate Management Committee. Specifications for the proposed computer are: 32 kB ROM, 16 kB RAM (up to 256 kB), six slots, color/mono display, 8-inch floppy disk drives, optional floating-point processor, joystick port, and printer port. Approval is given to build an operational microcomputer, code-named Acorn. They are given a deadline of one year to bring the new computer to market. [606.24] [620.110] [1149.170] [1256.139] [1299.152]
August 21
  • IBM meets with Microsoft again, to talk in general terms about their planned personal computers. IBM asks if Microsoft will develop some programming language interpreters/compilers for it. Bill Gates agrees to supply BASIC and other software development tools. IBM also asks for CP/M, but Gates says Digital Research would have to supply that. [266.271] [346.71] [906.469] [1149.171] [1299.153] [2324.106]
  • Bill Gates calls Gary Kildall, to arrange a meeting between IBM and Digital Research regarding CP/M. [1299.153] (September [1149.179])
    (adsbygoogle = window.adsbygoogle || []).push({});
August 22
  • IBM's Project Chess task force meets with Digital Research about using CP/M-86 for IBM's upcoming microcomputer. (Gary Kildall claims he agreed to provide CP/M-86 for IBM. IBM sources state that Gary Kildall was not interested.) [346.74] [620.110] [1299.155] [2324.106] (September [1149.179])
August 28
  • IBM representatives meet at Microsoft again. Bill Gates signs a consulting agreement for US$15,000 to develop the software specifications for IBM's personal computer. Jack Sams asks about alternatives to CP/M-86. Gates says he might find one. [266.272] [1299.156] [2324.107] (July [185.125]) (September [346.75]) (Microsoft proposes it to IBM [346.75])
September 28
  • At Microsoft, Bill Gates, Paul Allen and Kay Nishi make the final decision to accept the IBM contract to produce languages and an operating system for the new microcomputer. [1149.186]
September 30
  • Bill Gates, Bob O'Rear, and Steve Ballmer meet with IBM in Boca Raton, Florida, to deliver a report to IBM. They propose that Microsoft be put in charge of the entire software development process for IBM's new microcomputer, including providing the main operating system to run on the computer. Bill Gates insists on maintaining rights to the DOS, receiving royalty payments rather than a lump sum. [266.272] [346.73,76] [1299.161] (October [1149.188])
(month unknown)
  • At IBM, Don Estridge replaces Jack Sams on the Project Chess personal computer team. [1149.189]
November 6
  • Microsoft and IBM sign a formal contract for Microsoft to develop certain software products for IBM's new microcomputer. Microsoft will receive US$200,000 to adapt the operating system to the IBM PC, and US$500,000 for DOS, BASIC, and compilers. Microsoft is to have an initial version of the operating system and BASIC working by mid-January. [41] [266.273] [346.77] [1149.190] [1299.163] [1701.158]
  • IBM delivers the two PC prototypes to Microsoft, so they can begin developing BASIC and the machine's operating system. [346.78] [1149.190] (December [41])
(month unknown)
  • IBM promotes William Lowe from the Entry Systems Division to Vice President of IBM's laboratory in Rochester, Minnesota. [618.135]
  • Don Estridge replaces William Lowe in IBM's Entry Systems Division. [606.23] [618.135]
  • Shipments of IBM desktop computers in the US during the year: 6,000. [1150.D1]


January 12
  • Microsoft does not meet the delivery date for initial version of DOS and BASIC for IBM's PC project. [1149.196]
  • IBM shows Project Acorn to several members of ComputerLand, to get their suggestions. IBM informs them the computer name is IBM Personal Computer. [1702.125]
  • Microsoft operates 86-DOS for the first time on IBM's prototype microcomputer. [346.81] [1149.196] (January [1299.169])
  • IBM proposes to Matsushita Electric Industrial that they make small computers for IBM to sell. [1329.D6]
June 8
  • Info World magazine runs an article with details of IBM's personal computer project. [1149.201]
  • Microsoft persuades IBM to introduce its microcomputer with a minimum of 64 kB RAM. IBM had planned to only include 16 kB. [346.84]
  • Microsoft completes most work on 86-DOS for IBM's PC. [1149.199]
  • The first IBM PC computers roll off the assembly lines. [203.16]
July 21
  • Digital Research's Gary Kildall tells IBM that its PC-DOS software infringes his CP/M copyright. He says he will not sue if IBM sells CP/M on the IBM PC in addition to PC-DOS. [2324.107]
July 28
  • IBM's General Systems Division introduces its first desktop computer, the System 23 Datamaster. It uses a 16-bit 8086, and is a dedicated data processing machine. Price is US$9830. [41] [1149.201] [1237.34]
August 12
  • At the Waldorf-Astoria Hotel in New York City, and in Boca Raton, Florida, IBM announces the IBM Personal Computer, model 5150. The PC features a 4.77 MHz Intel 8088 CPU, 16 kB RAM (expandable to 256 kB), 40 kB ROM, one 5.25-inch floppy drive (160 kB capacity), for US$1565. A fully loaded version with color graphics costs US$6000. Also offered as options are PC-DOS 1.0 (Microsoft's MS-DOS) for US$40, Microsoft BASIC, VisiCalc, UCSD Pascal, CP/M-86 for US$240, and Easywriter 1.0. IBM will sell the new computer to consumers through Sears, Roebuck & Co. and ComputerLand. [9] [35] [41] [108] [120] [123] [146] [202.205] [205.28] [266.276] [277.14] [288.192] [346.86] [389.28] [415.48] [443.50] [606.27] [620.108,110] [716.237] [1128.25] [1150.D1] [1151.S3.1] [1149.204] [1239.38] [1256.139] [1298.188] [1644.149] [1702.155] [2324.107] [2605.94] (August 13 [862.170] [2442.86])
  • IBM introduces the Microsoft Adventure game for the IBM PC, Microsoft's first non-language non-OS software product. [1149.205]
  • IBM announces the CGA graphics card for the PC, giving 640x200 resolution with 16 colors. [117] [120]
  • Quote from Tandy president John Roach, regarding IBM's entry into the microcomputer field: "I don't think it's that significant". Quote from the financial vice-president of Tandy's Radio Shack division: "There definately is a new kid on the block, but there is nothing that IBM has presented that would blow the industry away". [346.87] [1239.38]
August 24
  • Apple Computer runs a full-page ad in the Wall Street Journal with a headline that reads "Welcome IBM. Seriously.". [46] [346.87] [606.26] [2605.68]
  • IBM begins shipping the IBM PC, ahead of schedule. [264.296] [606.26] [620.110] [1164.52] [1256.139] [1639.105]
  • At COMDEX, Tecmar introduces 20 add-on peripherals for the IBM PC. Tecmar is the first such third-party developer for the IBM PC. [203.19] (26 products [606.28])
  • Market share of personal computers: Radio Shack 20%, Apple Computer 17%, IBM 1.9%. [1316.S3.1]
  • Shipments of IBM PC computers to date: 13,533, valued at US$40-50 million. [606.28] [1060.S3.4] [1149.215] (20,000 [203.18]) (6500 [1702.157])


January 8
  • The US Justice Department decides to drop its antitrust suit against IBM, which was launched 13 years ago. One of its aims had been to break IBM up into several companies. [346.98] [930.186] [970.1] [1025.D3] [1041.D1] [1149.166] (June [606.11])
(month unknown)
  • 3Com begins investigating the application of Ethernet computer networking technology to IBM PC computers. [902.274]
  • IBM splits its Personal Computer development team into three groups: one to work on the PC XT, one to develop the PCjr, and one to start work on the PC AT. [41]
  • Xedex introduces the Baby Blue card (a Z80B processor on a plug-in card), allowing the IBM PC to run standard CP/M programs. Price: US$600. [346.92] [396.10] (April [9]) (Vendex company[346.93])
(month unknown)
  • At the West Coast Computer Faire, Davong Systems introduces its 5 MB Winchester Disk Drive for the IBM PC, for US$2000. [287.11]
  • Six months after the introduction of the IBM PC, 50,000 units have been sold. [1112.136] (after eight months [218])
April 5
  • The New York Times newspaper reports on page one that the IBM PC's BASIC contains a basic mathematical flaw. Entering 0.1 divided by 10 will result in a wrong answer. The culprit is a bug in Microsoft's floating-point math routine in the BASIC ROM chip. [1299.205]
  • IBM first offers Digital Research's CP/M-86 for the IBM PC. [346.90,262]
April 20
  • IBM opens its first personal computer product center store, in New York City. [1302.D5]
(month unknown)
  • Phase One Systems releases the Oasis-16 multi-user operating system for the IBM Personal Computer. Three-user support is built-in, with up to 32 users possible with bus expansion hardware. [995.20]
  • Microsoft ships its Multiplan spreadsheet program to IBM for testing and marketing for the IBM PC. [346.109]
  • Microsoft releases MS-DOS 1.1 to IBM, for the IBM PC. It supports 320 kB double-sided floppy disk drives. Microsoft also releases MS-DOS 1.25, similar to version 1.1 but for IBM-compatible computers. [146] [346.251] (June [346.263])
  • Columbia Data Products releases the Columbia MPC microcomputer. (This is the first IBM PC clone.) [9] [346.263] [1298.188]
  • At the COMDEX show, Dynalogic introduces the Hyperion microcomputer. The Hyperion is the first IBM-compatible portable microcomputer. [615.174]
(month unknown)
  • Mouse Systems introduces the first commercial mouse for the IBM PC. [176.112]
  • Microsoft releases the Flight Simulator game for the IBM PC. [1732.90]
  • IBM ships the 200,000th IBM PC. [447.458] [930.72] (800,000 [782.11])
  • Hercules Computer Technology announces the Hercules Graphics Card for the IBM PC, with monochrome graphics at 720x348 resolution. Price is US$499. [117] [120] (1983 [910.344])
September 15
  • Texas Instruments and IBM enter a joint agreement for Texas Instruments to produce chips for cards for networking office machines with computers. (This will become IBM's Token Ring LAN.) [1087.D5]
  • IBM begins marketing Microsoft Multiplan for the IBM PC. [346.109]
November 4
  • Compaq Computer introduces the Compaq Portable PC, compatible with the IBM PC. It features 4.77 MHz 8088, 128 kB RAM, 9-inch monochrome monitor, one 320 kB 5.25-inch disk drive. Price is US$2995; weight is 28 pounds. It cost Compaq US$1 million to create an IBM-compatible ROM BIOS that did not violate IBM's copyright. The computer is expected to be availble in early 1983. [1] [108] [117] [346.263] [618.171] [1165.D5] [1256.141] [1298.188]
  • Satellite Software International introduces the WordPerfect word processing program for the IBM PC. [330.108] (October [502.49])
  • At the COMDEX show, Visicorp announces the VisiOn graphical user interface for the IBM PC. It is the first graphical windowing environment that can run multiple applications on MS-DOS. Price is US$299. Code-name of the product was Quasar. [346.176] [477.158] [909.228,236] [1149.251] [1299.219] [1303.37]
  • At the COMDEX show, Lotus Development announces the Lotus 1-2-3 spreadsheet program for the IBM PC. Price is US$495. [41] [346.111] [1149.229] [1303.37] (October [9])
  • Shipments of IBM PC computers during the year: 150,000-180,000. [444.493] [997.D5] [1702.157]
  • Market share of personal computers for the year: IBM 18.8%. [902.136]

End of 1952-1982. Next: 1983.
The complete timeline can be purchased in a PDF file for US$10 from the author.

You can pay now directly via PayPal. When I receive notification from PayPal, I will email you the PDF file.
Solution Graphics
or to request my mailing address to mail payment.

1952-1982 1983-1986 1987-1991 1992-1995 1996-end

A list of references to all source material is available.

Other web pages of interest: