Tim Paterson

Last updated

Tim Paterson
Born (1956-06-01) 1 June 1956 (age 67)
Alma mater University of Washington
Occupation(s) Computer programmer, software designer
Known for Z-80 SoftCard, 86-DOS, MSX-DOS

Tim Paterson (born 1 June 1956) is an American computer programmer, best known for creating 86-DOS, an operating system for the Intel 8086. This system emulated the application programming interface (API) of CP/M, which was created by Gary Kildall. 86-DOS later formed the basis of MS-DOS, the most widely used personal computer operating system in the 1980s.



Paterson was educated in the Seattle Public Schools, graduating from Ingraham High School in 1974. He attended the University of Washington, working as a repair technician for The Retail Computer Store in the Green Lake area of Seattle, Washington, and graduated magna cum laude with a degree in Computer Science [1] in June 1978. He went to work for Seattle Computer Products as a designer and engineer. [1] He designed the hardware of Microsoft's Z-80 SoftCard which had a Z80 CPU and ran the CP/M operating system on an Apple II.

A month later, Intel released the 8086 CPU, and Paterson went to work designing an S-100 8086 board, which went to market in November 1979. The only commercial software that existed for the board was Microsoft's Standalone Disk BASIC-86. The standard CP/M operating system at the time was not available for this CPU and without a true operating system, sales were slow. Paterson began work on QDOS (Quick and Dirty Operating System) in April 1980 to fill that void, copying the APIs of CP/M from references, including the published CP/M manual, so that it would be highly compatible. QDOS was soon renamed as 86-DOS. Version 0.10 was complete by July 1980. By version 1.14, 86-DOS had grown to 4000 lines of assembly code. [2] In December 1980, Microsoft secured the rights to market 86-DOS to other hardware manufacturers. [3]

While acknowledging that he made 86-DOS compatible with CP/M, [4] Paterson has maintained that the 86-DOS program was his original work and has denied allegations that he referred to CP/M code while writing it. [5] When a book appeared in 2004 claiming that 86-DOS was an unoriginal "rip-off" of CP/M, [6] Paterson sued the authors and publishers for defamation. [7] [8] The judge found that Paterson failed to "provide any evidence regarding 'serious doubts' about the accuracy of the Gary Kildall chapter. Instead, a careful review of the Lefer notes ... provides a research picture tellingly close to the substance of the final chapter" and the case was dismissed on the basis that the book's claims were constitutionally protected opinions and not provably false. [9] Gary Kildall Gary Kildall - The Man That Should Have Been Bill Gates - Part II

Paterson left SCP in April 1981 and worked for Microsoft from May 1981 to April 1982. Microsoft renamed 86-DOS to MS-DOS on 27 July 1981. After a brief second stint with SCP, Paterson started his own company, Falcon Technology, a.k.a. Falcon Systems. [1] In 1983, Microsoft contracted Paterson to port MS-DOS to the MSX computers standard they were developing with ASCII Corporation. Paterson accepted the contract to help fund his company and completed the work on the MSX-DOS operating system in 1984. [10] Falcon Technology was bought by Microsoft in 1986 to reclaim one out of two issued royalty-free licenses for MS-DOS (the other belonging to SCP), [11] eventually becoming part of Phoenix Technologies. [1] Paterson worked a second stint with Microsoft from 1986 to 1988, [1] and a third stint from 1990 to 1998, during which time he worked on Visual Basic. [1]

After leaving Microsoft a third time, Paterson founded another software development company, Paterson Technology, and also made several appearances on the Comedy Central television program BattleBots . Paterson has also raced rally cars in the SCCA Pro Rally series, and even engineered his own trip computer, which he integrated into the axle of a four-wheel-drive Porsche 911.

Related Research Articles

<span class="mw-page-title-main">Gary Kildall</span> American computer scientist and microcomputer entrepreneur (1942–1994)

Gary Arlen Kildall was an American computer scientist and microcomputer entrepreneur.

<span class="mw-page-title-main">CP/M</span> Discontinued family of computer operating systems

CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc. Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors.

<span class="mw-page-title-main">Digital Research</span> Defunct American software company

Digital Research, Inc. was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser DOS, DOS Plus, DR DOS and GEM. It was the first large software company in the microcomputer world. Digital Research was originally based in Pacific Grove, California, later in Monterey, California.

MP/M is a discontinued multi-user version of the CP/M operating system, created by Digital Research developer Tom Rolander in 1979. It allowed multiple users to connect to a single computer, each using a separate terminal.

<span class="mw-page-title-main">IBM PC DOS</span> Computer operating system

IBM PC DOS, an acronym for IBM Personal Computer Disk Operating System, is a discontinued disk operating system for the IBM Personal Computer, its successors, and IBM PC compatibles. It was manufactured and sold by IBM from the early 1980s into the 2000s. Developed by Microsoft, it was also sold by that company as MS-DOS. Both operating systems were identical or almost identical until 1993, when IBM began selling PC DOS 6.1 with new features. The collective shorthand for PC DOS and MS-DOS was DOS, which is also the generic term for disk operating system, and is shared with dozens of disk operating systems called DOS.

dir (command) Directory information command on various operating systems

In computing, dir (directory) is a command in various computer operating systems used for computer file and directory listing. It is one of the basic commands to help navigate the file system. The command is usually implemented as an internal command in the command-line interpreter (shell). On some systems, a more graphical representation of the directory structure can be displayed using the tree command.

<span class="mw-page-title-main">CP/M-86</span> Discontinued computer operating system for x86 processors

CP/M-86 was a version of the CP/M operating system that Digital Research (DR) made for the Intel 8086 and Intel 8088. The system commands are the same as in CP/M-80. Executable files used the relocatable .CMD file format. Digital Research also produced a multi-user multitasking operating system compatible with CP/M-86, MP/M-86, which later evolved into Concurrent CP/M-86. When an emulator was added to provide PC DOS compatibility, the system was renamed Concurrent DOS, which later became Multiuser DOS, of which REAL/32 is the latest incarnation. The FlexOS, DOS Plus, and DR DOS families of operating systems started as derivations of Concurrent DOS as well.

<span class="mw-page-title-main">86-DOS</span> Discontinued computer operating system for x86 processors and predecessor to MS-DOS/PC DOS

86-DOS is a discontinued operating system developed and marketed by Seattle Computer Products (SCP) for its Intel 8086-based computer kit.

<span class="mw-page-title-main">IBMBIO.COM</span> System file (DOS BIOS) in PC DOS and DR-DOS

IBMBIO.COM is a system file in many DOS operating systems. It contains the system initialization code and all built-in device drivers. It also loads the DOS kernel (IBMDOS.COM) and optional pre-loadable system components, displays boot menus, processes configuration files and launches the shell.

<span class="mw-page-title-main">Seattle Computer Products</span> 1970s–1980s American microcomputer hardware company

Seattle Computer Products (SCP) was a Tukwila, Washington, microcomputer hardware company which was one of the first manufacturers of computer systems based on the 16-bit Intel 8086 processor. Founded in 1978, SCP began shipping its first S-100 bus 8086 CPU boards to customers in November 1979, about 21 months before IBM introduced its Personal Computer which was based on the slower 8088 and introduced the 8-bit ISA bus. SCP shipped an operating system for that hardware about a year before the release of the PC, which was modified by Microsoft for the PC and renamed IBM PC DOS. SCP was staffed partly by high-school students from nearby communities who soldered and assembled the computers. Some of them would later work for Microsoft.

This article details versions of MS-DOS, IBM PC DOS, and at least partially compatible disk operating systems. It does not include the many other operating systems called "DOS" which are unrelated to IBM PC compatibles.

Marc B. McDonald is an American who was Microsoft's first salaried employee.

A source-to-source translator, source-to-source compiler, transcompiler, or transpiler is a type of translator that takes the source code of a program written in a programming language as its input and produces an equivalent source code in the same or a different programming language. A source-to-source translator converts between programming languages that operate at approximately the same level of abstraction, while a traditional compiler translates from a higher level programming language to a lower level programming language. For example, a source-to-source translator may perform a translation of a program from Python to JavaScript, while a traditional compiler translates from a language like C to assembler or Java to bytecode. An automatic parallelizing compiler will frequently take in a high level language program as an input and then transform the code and annotate it with parallel code annotations or language constructs.

MSX-DOS is a discontinued disk operating system developed by Microsoft for the 8-bit home computer standard MSX, and is a cross between MS-DOS v1.25 and CP/M-80 v2.2.

copy (command)

In computing, copy is a command in various operating systems. The command copies computer files from one directory to another.

This article presents a timeline of events in the history of 16-bit x86 DOS-family disk operating systems from 1980 to present. Non-x86 operating systems named "DOS" are not part of the scope of this timeline.

<span class="mw-page-title-main">DOS</span> Group of closely related IBM PC-compatible operating systems

DOS is a family of disk-based operating systems for IBM PC compatible computers. The DOS family primarily consists of Microsoft's MS-DOS and a rebranded version, IBM PC DOS, both of which were introduced in 1981. Later compatible systems from other manufacturers include DR-DOS (1988), ROM-DOS (1989), PTS-DOS (1993), and FreeDOS (1998). MS-DOS dominated the IBM PC compatible market between 1981 and 1995.

<span class="mw-page-title-main">Tom Rolander</span> American computer engineer and entrepreneur, known for MP/M

Thomas Alan Rolander is an American entrepreneur, engineer, and developer of the multitasking multiuser operating system MP/M created for microcomputers in 1979 while working as one of the first employees of Digital Research with Gary Kildall, the "father" of CP/M. CP/M and MP/M laid the groundwork to later Digital Research operating system families such as Concurrent CP/M, Concurrent DOS and Multiuser DOS. He also developed CP/NET.

Kathryn Betty Strutynski was a mathematician and computer scientist, and attended University at Brigham Young University and the Naval Postgraduate School. Besides jobs at Pan Am Airways and Bechtel Corporation, she worked at Digital Research, where she contributed to the development of CP/M, the first mainstream operating system for microcomputers.


  1. 1 2 3 4 5 6 Schulman, Andrew; Michels, Raymond J.; Kyle, Jim; Paterson, Tim; Maxey, David; Brown, Ralf D. (1990). Undocumented DOS: A programmer's guide to reserved MS-DOS functions and data structures (1 ed.). Addison-Wesley. ISBN   978-0-201-57064-9. ark:/13960/t14n8vs6f. Retrieved 2022-11-26. (xviii+694+viii pages, 2 5.25"-floppies) Errata:
  2. Zbikowski, Mark; Allen, Paul; Ballmer, Steve; Borman, Reuben; Borman, Rob; Butler, John; Carroll, Chuck; Chamberlain, Mark; Chell, David; Colee, Mike; Courtney, Mike; Dryfoos, Mike; Duncan, Rachel; Eckhardt, Kurt; Evans, Eric; Farmer, Rick; Gates, Bill; Geary, Michael; Griffin, Bob; Hogarth, Doug; Johnson, James W.; Kermaani, Kaamel; King, Adrian; Koch, Reed; Landowski, James; Larson, Chris; Lennon, Thomas; Lipkie, Dan; McDonald, Marc; McKinney, Bruce; Martin, Pascal; Mathers, Estelle; Matthews, Bob; Melin, David; Mergentime, Charles; Nevin, Randy; Newell, Dan; Newell, Tani; Norris, David; O'Leary, Mike; O'Rear, Bob; Olsson, Mike; Osterman, Larry; Ostling, Ridge; Pai, Sunil; Paterson, Tim; Perez, Gary; Peters, Chris; Petzold, Charles; Pollock, John; Reynolds, Aaron; Rubin, Darryl; Ryan, Ralph; Schulmeisters, Karl; Shah, Rajen; Shaw, Barry; Short, Anthony; Slivka, Ben; Smirl, Jon; Stillmaker, Betty; Stoddard, John; Tillman, Dennis; Whitten, Greg; Yount, Natalie; Zeck, Steve (1988). "Technical advisors". The MS-DOS Encyclopedia: versions 1.0 through 3.2. By Duncan, Ray; Bostwick, Steve; Burgoyne, Keith; Byers, Robert A.; Hogan, Thom; Kyle, Jim; Letwin, Gordon; Petzold, Charles; Rabinowitz, Chip; Tomlin, Jim; Wilton, Richard; Wolverton, Van; Wong, William; Woodcock, JoAnne (Completely reworked ed.). Redmond, Washington, USA: Microsoft Press. p. 20. ISBN   978-1-55615-049-4. LCCN   87-21452. OCLC   16581341. (xix+1570 pages; 26 cm) (NB. This edition was published in 1988 after extensive rework of the withdrawn 1986 first edition by a different team of authors. While mostly based on DOS 3.2, this book has an appendix covering changes introduced with DOS 3.3.)
  3. "86-DOS version 0.3 (1980-11-15) License Agreement between Seattle Computer Products and Microsoft" (PDF). 1981-01-06. Archived (PDF) from the original on 2020-02-18. Retrieved 2013-04-01. (NB. Published as part of the Comes v. Microsoft case as exhibit #1.)
  4. Paterson, Tim (June 1983). "An Inside Look at MS-DOS - The design decisions behind the popular operating system". BYTE . 16-Bit Designs. Vol. 8, no. 6. pp.  230. ISSN   0360-5280 . Retrieved 2013-10-19. (NB. The article uses "MS-DOS" throughout to refer to both 86-DOS and MS-DOS, but mentions QDOS and 86-DOS in a sidebar article, "A Short History of MS-DOS".)
  5. Paterson, Tim (1994-10-03). "From the Mailbox: The Origins of DOS" (PDF). Microprocessor Report . Vol. 8, no. 13. MicroDesign Resources. Archived from the original (PDF) on 2003-12-04. Retrieved 2006-11-20.
  6. Evans, Harold; Buckland, Gail; Lefer, David (2004). They Made America: From the Steam Engine to the Search Engine: Two Centuries of Innovators . Little, Brown and Company. ISBN   978-0-316-27766-2.
  7. The Associated Press (2005-03-02). Seattle Post-Intelligencer (ed.). "Programmer sues author over role in Microsoft history". USA Today . Seattle, Washington, USA. Archived from the original on 2020-02-18. Retrieved 2006-11-20.
  8. United States District Court for the Western District of Washington (2007-07-25) [2005-02-28]. "Paterson v. Little, Brown, and Co., et al. - Order" (PDF). Seattle Times . Seattle, Washington, USA. Case 2:05-cv-01719-TSZ Document 29. Archived from the original (PDF) on 2018-10-03. Retrieved 2014-12-21.
  9. Orlowski, Andrew (2007-07-30). "MS-DOS paternity suit settled - Computer pioneer Kildall vindicated, from beyond the grave". The Register . The Channel. Archived from the original on 2020-02-07. Retrieved 2007-07-31.
  10. Paterson, Tim (2014-02-17). "The History of MSX-DOS". Jorito, Maggoo, John Hassink, MSX Resource Center. Archived from the original on 2020-02-18. Retrieved 2014-05-31.
  11. Lach, Eric (1986-09-29). "Microsoft buys major assets of Falcon, reclaims royalty-free MS-DOS license". InfoWorld - The PC News Weekly. Vol. 8, no. 39. Redmond, Washington, USA: Popular Computing, Inc., CW Communications, Inc. p. 27. ISSN   0199-6649 . Retrieved 2014-08-13.