Tim Paterson (born June 1, 1956) is the American programmer best known for creating QDOS (Quick and Dirty Operating System), later renamed 86-DOS, while working at Seattle Computer Products (SCP). This became the foundation for MS-DOS after Microsoft licensed and then purchased it.
Background and Time at SCP Paterson grew up in Seattle, graduating from Ingraham High School in 1974. He attended the University of Washington, working as a computer repair technician at a local store, and earned a Computer Science degree magna cum laude in 1978.Shortly after graduating, at age 22, he joined Seattle Computer Products (a small Tukwila, Washington-based company founded by Rod Brock) as a designer and engineer. SCP specialized in S-100 bus hardware and was one of the first to release an Intel 8086 CPU board in November 1979.Sales were sluggish because no major operating system supported the 8086 yet—Digital Research’s CP/M-86 was delayed.
To demonstrate and sell their hardware, Paterson developed QDOS single-handedly starting in April 1980. He designed it to be highly compatible with CP/M’s API (using public manuals as reference) so existing software could run with minimal changes.By July 1980, version 0.10 was ready; it evolved into 86-DOS by late 1980 (around 4,000 lines of assembly code).
Microsoft licensed it in December 1980 for $25,000 (non-exclusive), then bought full rights in July 1981 for an additional amount (total often cited around $50,000–$75,000). Paterson has always maintained it was original work, not copied code, and even sued for defamation over a 2004 book claiming otherwise (the case was dismissed).Career After SCPIn May 1981,
Paterson left SCP to join Microsoft full-time, helping adapt 86-DOS into PC-DOS for the IBM PC (released August 1981). He worked there briefly, then returned to SCP/Falcon Technology (an SCP spin-off).He had multiple stints at Microsoft: 1986–1988 and 1990–1998, contributing to Visual Basic among other projects.After leaving Microsoft for good in 1998, he founded Paterson Technology, his own software company.Other InterestsBeyond programming, he’s appeared on the TV show BattleBots with robot entries and has been an avid rally car racer in the SCCA Pro Rally series (even building custom tech like a trip computer for his Porsche 911).He’s often called the “Father of DOS,” 🙂
though the massive success came from Microsoft’s licensing and IBM’s adoption. As of recent public info (up to around 2020s), he keeps a low profile but has shared his story in interviews and blogs about early PC history.If you’d like details on a specific part (like the CP/M controversy or his later work), let me know!
