Tim Patterson writes QDOS, forerunner of the MS-DOS microcomputer operating system, in Tukwila in April 1980.

  • By David Wilma
  • Posted 1/01/2000
  • HistoryLink.org Essay 2118

In April 1980, Tim Patterson of Seattle Computer Products in Tukwila, writes QDOS (Quick and Dirty Operating System) for the Intel 8086 microprocesser (or chip), at the time the most advanced chip for desktop computers. QDOS is the forerunner of MS-DOS.

In October 1980, Seattle Computer Products sold the system to Microsoft of Bellevue, which was secretly developing computer language for IBM.

Patterson participated in further work on a new operating system without knowing the identity of Microsoft's client. This effort resulted in MS-DOS (Microsoft Disk Operating System), at the beginning of the twenty-first century the operating system on which the vast majority of the world's desktop computers are based.


Adam Woog, Sexless Oysters and Self-Tipping Hats: 100 Years of Inventions in the Pacific Northwest (Seattle: Sasquatch Books, 1991), 216-220; Daniel Ichbiah and Susan P. Kneper, The Making of Microsoft (Rocklin, CA: Prime Publishing, 1991), 138-142.

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