Gary Kildall

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Gary Kildall
Born(1942-05-19)May 19, 1942
Seattle, Washington, U.S.
DiedJuly 11, 1994(1994-07-11) (aged 52)
Resting placeEvergreen Washelli Memorial Park
Alma materUniversity of Washington[1][2]
  • Computer scientist
  • entrepreneur
Years active1972–1994
Known for
TitleFounder, chairman and CEO of Digital Research
Board member ofDigital Research
Spouse(s)Dorothy McEwen Kildall
Karen Kildall[3]
ChildrenScott and Kristen[4]

Gary Arlen Kildall (/ˈkɪldˌɔːl/; May 19, 1942 – July 11, 1994) was an American computer scientist and microcomputer entrepreneur.

During the 1970s, Kildall created the CP/M operating system among other operating systems and programming tools,[5] and subsequently founded Digital Research, Inc. (or "DRI") to market and sell his software products. Kildall was among the earliest individuals to recognize microprocessors as fully capable computers (rather than simply as equipment controllers), and to organize a company around this concept.[6] Due to his accomplishments during this era, Kildall is considered a pioneer of the personal computer revolution.[6][7]

During the 1980s, Kildall also appeared on PBS as co-host (with Stewart Cheifet) of Computer Chronicles, a weekly informational program which covered the latest developments in personal computing.

Although Kildall's entrepreneurial career in computing spanned more than two decades, he is mainly remembered in connection with his development of the CP/M operating system, an early multi-platform microcomputer OS that has many parallels to the later MS-DOS used on the IBM PC.

Early life[edit]

Gary Kildall was born and grew up in Seattle, Washington, where his family operated a seamanship school. His father, Joseph Kildall, was a captain of Norwegian heritage. His mother Emma was of half Swedish descent, as Kildall's grandmother was born in Långbäck, Sweden, in Skellefteå Municipality, but emigrated to Canada at 23 years of age.[8]

A self-described "greaser" during high school,[5]: 12  Kildall later attended the University of Washington (UW), hoping to become a mathematics teacher. During his studies, Kildall became increasingly interested in computer technology. After receiving his degree in 1972,[1][9] he fulfilled a draft obligation to the United States Navy by teaching at the Naval Postgraduate School (NPS) in Monterey, California.[10] Being within an hour's drive of Silicon Valley, Kildall heard about the first commercially available microprocessor, the Intel 4004. He bought one of the processors and began writing experimental programs for it. To learn more about the processors, he worked at Intel as a consultant on his days off.

Kildall briefly returned to UW and finished his doctorate in computer science in 1972,[2] then resumed teaching at NPS. He published a paper that introduced the theory of data-flow analysis used today in optimizing compilers[11] (sometimes known as Kildall's method), and he continued to experiment with microcomputers and the emerging technology of floppy disks. Intel lent him systems using the 8008 and 8080 processors, and in 1973, he developed the first high-level programming language for microprocessors, called PL/M.[10] For Intel he also wrote an 8080 instruction set simulator named INTERP/80. He created CP/M the same year to enable the 8080 to control a floppy drive, combining for the first time all the essential components of a computer at the microcomputer scale. He demonstrated CP/M to Intel, but Intel had little interest and chose to market PL/M instead.[10]

Business career[edit]


Kildall and his wife Dorothy established a company, originally called "Intergalactic Digital Research" (later renamed as Digital Research, Inc.), to market CP/M through advertisements in hobbyist magazines. Digital Research licensed CP/M for the IMSAI 8080, a popular clone of the Altair 8800. As more manufacturers licensed CP/M, it became a de facto standard and had to support an increasing number of hardware variations. In response, Kildall pioneered the concept of a BIOS, a set of simple programs stored in the computer hardware (ROM or EPROM chip) that enabled CP/M to run on different systems without modification.[10]

CP/M's quick success took Kildall by surprise, and he was slow to update it for high density floppy disks and hard disk drives.[citation needed] After hardware manufacturers talked about creating a rival operating system, Kildall started a rush project to develop CP/M 2.[12] By 1981, at the peak of its popularity, CP/M ran on 3000 different computer models and DRI had US$5.4 million in yearly revenues.[10]

IBM dealings[edit]

IBM approached Digital Research in 1980, at Bill Gates' suggestion,[13] to negotiate the purchase of a forthcoming version of CP/M called CP/M-86 for the IBM PC. Gary had left negotiations to his wife, Dorothy, as he usually did, while he and colleague and developer of MP/M operating system Tom Rolander used Gary's private aeroplane to deliver software to manufacturer Bill Godbout.[6][14] Before the IBM representatives would explain the purpose of their visit, they insisted that Dorothy sign a non-disclosure agreement. On the advice of DRI attorney Gerry Davis, Dorothy refused to sign the agreement without Gary's approval. Gary returned in the afternoon and tried to move the discussion with IBM forward, and accounts disagree on whether he signed the non-disclosure agreement, as well as if he ever met with the IBM representatives.[15]

Various reasons have been given for the two companies failing to reach an agreement. DRI, which had only a few products, might have been unwilling to sell its main product to IBM for a one-time payment rather than its usual royalty-based plan.[16] Dorothy might have believed that the company could not deliver CP/M-86 on IBM's proposed schedule, as the company was busy developing an implementation of the PL/I programming language for Data General.[7] Also possible, the IBM representatives might have been annoyed that DRI had spent hours on what they considered a routine formality.[14] According to Kildall, the IBM representatives took the same flight to Florida that night that he and Dorothy took for their vacation, and they negotiated further on the flight, reaching a handshake agreement. IBM lead negotiator Jack Sams insisted that he never met Gary, and one IBM colleague has confirmed that Sams said so at the time. He accepted that someone else in his group might have been on the same flight, and noted that he flew back to Seattle to talk with Microsoft again.[14]

Sams related the story to Gates, who had already agreed to provide a BASIC interpreter and several other programs for the PC. Gates' impression of the story was that Gary capriciously "went flying", as he would later tell reporters.[17] Sams left Gates with the task of finding a usable operating system, and a few weeks later he proposed using the operating system 86-DOS—an independently developed operating system that implemented Kildall's CP/M API—from Seattle Computer Products (SCP). Paul Allen negotiated a licensing deal with SCP. Allen had 86-DOS adapted for IBM's hardware, and IBM shipped it as IBM PC DOS.[15]

Kildall obtained a copy of PC DOS, examined it, and concluded that it infringed on CP/M. When he asked Gerry Davis what legal options were available, Davis told him that intellectual property law for software was not clear enough to sue.[18] Instead Kildall only threatened IBM with legal action, and IBM responded with a proposal to offer CP/M-86 as an option for the PC in return for a release of liability.[19] Kildall accepted, believing that IBM's new system (like its previous personal computers) would not be a significant commercial success.[20] When the IBM PC was introduced, IBM sold its operating system as an unbundled option. One of the operating system options was PC DOS, priced at US$40. PC DOS was seen as a practically necessary option; most software titles required it and without it the IBM PC was limited to its built-in Cassette BASIC. CP/M-86 shipped a few months later six times more expensive at US$240, and sold poorly against DOS and enjoyed far less software support.[6]

Later work[edit]

With the loss of the IBM deal, Gary and Dorothy found themselves under pressure to bring in more experienced management, and Gary's influence over the company waned. He worked in various experimental and research projects, such as a version of CP/M with multitasking (MP/M) and an implementation of the Logo programming language.[10] He hoped that Logo, an educational dialect of LISP, would supplant BASIC in education, but it did not.[21] After seeing a demonstration of the Apple Lisa, Kildall oversaw the creation of DRI's own graphical user interface, called GEM. Novell acquired DRI in 1991 in a deal that netted millions for Kildall.[18]

Kildall resigned as CEO of Digital Research on 28 June 1985, but remained chairman of the board.[22]

Kildall also pursued computing-related projects outside DRI. During the seven years from 1983 to 1990 he co-hosted a public television program on the side, called Computer Chronicles, that followed trends in personal computing.

In 1984 he started another company, Activenture, which adapted optical disc technology for computer use.[23] In early 1985 it was renamed KnowledgeSet and released the first computer encyclopedia in June 1985, a CD-ROM version of Grolier's Academic American Encyclopedia[15][23][7] named The Electronic Encyclopedia,[24] later acquired by Banta Corporation.[25] Kildall's final business venture, known as Prometheus Light and Sound (PLS) and based in Austin, Texas, developed a modular PBX communication system[10] that integrated land-line telephones with mobile phones (called "Intelliphone") to reduce the then-high online costs and to remotely connect with home appliances.[26] It included a UUCP-based store and forward system to exchange emails and files between the various nodes and was planned to include TCP/IP support at a later point in time.

Personal life[edit]

Kildall's colleagues recall him as creative, easygoing, and adventurous. In addition to flying, he loved sports cars, auto racing, and boating, and had a lifelong love of the sea.[6][10]

I think I’ll make a cassette tape of the ‘IBM Flying Story.’ I’ll carry a few copies in my jacket to give out on occasion. There’s only one problem. I [will] tell this story [to someone], and after I’m done, the same person [will say], ‘Yeah, but did you go flying and blow IBM off?’

Gary Kildall, Computer Connections[7]

Although Kildall preferred to leave the IBM affair in the past and to be known for his work before and afterward, he continually faced comparisons between himself and Bill Gates, as well as fading memories of his contributions. A legend grew around the fateful IBM-DRI meeting, encouraged by Gates and various journalists,[17][27] suggesting that Kildall had irresponsibly taken the day off for a recreational flight.[7]

In later years, Kildall privately expressed bitter feelings about being overshadowed by Microsoft,[10] and began suffering from alcoholism.[18][28]

Selling DRI to Novell had made Kildall a wealthy man, and he moved to the West Lake Hills suburb of Austin. His Austin house was a lakeside property, with stalls for several sports cars, and a video studio in the basement. Kildall owned and flew his own Learjet and had at least one boat on the lake. While in Austin he also participated in volunteer efforts to assist children with HIV/AIDS. He also owned a mansion with a panoramic ocean view in Pebble Beach, California, near the headquarters of DRI.

Computer Connections[edit]

In 1992, Kildall was invited to the University of Washington computer science program's 25th anniversary event. As a distinguished graduate of the program, Kildall was disappointed when asked to attend simply as an audience member. He also took offense at the decision to give the keynote speech to Bill Gates, a Harvard dropout who had donated to UW, but had never attended.[7]

In response, Kildall began writing a memoir, entitled Computer Connections: People, Places, and Events in the Evolution of the Personal Computer Industry.[18] The memoir,[29][30][5] which Kildall sought to publish, expressed his frustration that people did not seem to value elegance in computer software.[21]

Don't think for a minute that [Bill] Gates made it 'big time' because of his technical savvy.

Gary Kildall, Computer Connections[5]: 62 

Writing about Bill Gates, Kildall described him as "more of an opportunist than a technical type, and severely opinionated, even when the opinion he holds is absurd."[5]: 62 

In an appendix, he called DOS "plain and simple theft"[31] because its first 26 system calls worked the same as CP/M's.[32] He accused IBM of contriving the price difference between PC DOS and CP/M-86 in order to marginalize CP/M.[7]

Kildall had completed a rough draft of the manuscript by the end of 1993,[5] but the full text remains unpublished. Journalist Harold Evans used the memoir as a primary source for a chapter about Kildall in the 2004 book They Made America, concluding that Microsoft had robbed Kildall of his inventions.[7] IBM veterans from the PC project disputed the book's description of events, and Microsoft described it as "one-sided and inaccurate."[18]

In August 2016, Kildall's family made the first seven chapters of Computer Connections available as a free public download.[30][29][5]


On July 8, 1994, at the age of 52,[9] Kildall sustained a head injury at the Franklin Street Bar & Grill, a biker bar in Monterey, California.[33] The exact circumstances of the injury are unclear. Various sources have claimed he fell from a chair, fell down steps, or was assaulted because he had entered the establishment wearing Harley-Davidson leathers.[16] Harold Evans, in They Made America, states that Kildall "stumbled and hit his head" inside the premises, and "was found on the floor."[7]

Following the injury, Kildall was discharged from the hospital twice. He was pronounced dead at the Community Hospital of the Monterey Peninsula, on July 11, 1994.

An autopsy, conducted on July 12, did not conclusively determine the cause of death.[32][4] Evans states that Kildall's head injury triggered a cerebral hemorrhage, causing a blood clot to form inside the skull.[7] A CP/M Usenet FAQ states that Kildall was concussed due to his injury, and died of a heart attack; the connection between the two is unclear.[34]

Initial news reports and police investigation viewed Kildall's death as a possible homicide. According to the coroner's report, Kildall's fatal injury may have taken place "as a result of foul play," and the case was referred to the Monterey Police Department. "We're going to investigate it as a possible homicide," said police Sgt. Frank Sollecito. "I'm not going to flat-out say it's a homicide."[35]

Kildall's body was cremated. His remains were buried in Evergreen Washelli Memorial Park, in north Seattle.[7]


Following the announcement of Kildall's death, Bill Gates commented that he was "one of the original pioneers of the PC revolution" and "a very creative computer scientist who did excellent work. Although we were competitors, I always had tremendous respect for his contributions to the PC industry. His untimely death was very unfortunate and his work will be missed."[6]

In March 1995, Kildall was posthumously honored by the Software Publishers Association (SPA) for his contributions to the microcomputer industry:[36][37][10]

In April 2014, the city of Pacific Grove installed a commemorative plaque outside Kildall's former residence, which also served as the early headquarters of Digital Research.[43]

See also[edit]


  1. ^ a b Kildall, Gary Arlen (December 1968). Experiments in large-scale computer direct access storage manipulation (M.Sc. thesis). University of Washington. Thesis No. 17341.
  2. ^ a b Kildall, Gary Arlen (May 1972). Global expression optimization during compilation (Ph.D. dissertation). Seattle, Washington, USA: University of Washington, Computer Science Group. Thesis No. 20506, Technical Report No. 72-06-02.
  3. ^ O'Connor, Rory J. "PC pioneer Kildall dies in Monterey". Retrieved 2022-01-19.
  4. ^ a b Markoff, John Gregory (1994-07-13). "Gary Kildall, 52, Crucial Player In Computer Development, Dies". The New York Times. p. D19. Archived from the original on 2017-08-24.
  5. ^ a b c d e f g Kildall, Gary Arlen (2016-08-02) [1993]. Kildall, Scott; Kildall, Kristin (eds.). Computer Connections: People, Places, and Events in the Evolution of the Personal Computer Industry (Manuscript, part 1). Kildall Family. Archived from the original on 2016-11-17. Retrieved 2016-11-17.
  6. ^ a b c d e f "Special Edition: Gary Kildall". The Computer Chronicles. 1995. Archived from the original on 2014-07-02. Retrieved 2014-06-13.
  7. ^ a b c d e f g h i j k 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.
  8. ^ Andersson, Ulrika (2009-01-19). "Skellefteåättling kunde ha varit Bill Gates". Norra Västerbotten (in Swedish). Archived from the original on 2009-05-24. Retrieved 2009-05-07.
  9. ^ a b Bishop, Todd (2014-04-25). "'A real inventor': UW's Gary Kildall, father of the PC operating system, honored for key work". GeekWire. Retrieved 2022-06-22.
  10. ^ a b c d e f g h i j Swaine, Michael (1997-04-01). "Gary Kildall and Collegial Entrepreneurship". Dr. Dobb's Journal. Archived from the original on 2007-01-24. Retrieved 2006-11-20.
  11. ^ Kildall, Gary Arlen (1973-10-01). "A Unified Approach to Global Program Optimization" (PDF). Proceedings of the 1st Annual ACM SIGACT-SIGPLAN Symposium on Principles of Programming Languages (POPL). Boston, Massachusetts, USA: 194–206. doi:10.1145/512927.512945. hdl:10945/42162. S2CID 10219496. Archived (PDF) from the original on 2017-06-29. Retrieved 2006-11-20. ([1])
  12. ^ Eubanks, Gordon. Akass, Clive (ed.). "Interview: Gordon Eubanks, Former Student & CEO of Oblix, Inc". Recollections of Gary Kildall (Interview). Archived from the original on 2006-12-09. Retrieved 2006-11-30.
  13. ^ Isaacson, Walter (2014). The Innovators: How a Group of Inventors, Hackers, Geniuses, and Geeks Created the Digital Revolution. Simon & Schuster. p. 358. ISBN 978-1476708690.
  14. ^ a b c Wallace, James; Erickson, Jim (1993). Hard Drive: Bill Gates and the Making of the Microsoft Empire. New York: HarperBusiness. ISBN 0-88730-629-2.
  15. ^ a b c Freiberger, Paul; Swaine, Michael (2000) [1984]. Fire in the Valley: The Making of the Personal Computer (2nd ed.). New York, N.Y., USA: McGraw-Hill. ISBN 0-07-135892-7.
  16. ^ a b Young, Jeffrey (1997-07-07). "Gary Kildall: The DOS That Wasn't". Forbes. Archived from the original on 2011-06-23. Retrieved 2011-08-29.
  17. ^ a b Manes, Stephen; Andrews, Paul (1992). Gates: How Microsoft's Mogul Reinvented an Industry—and Made Himself the Richest Man in America. Doubleday. ISBN 0-671-88074-8.
  18. ^ a b c d e Hamm, Steve; Greene, Jay (2004-10-25). "The Man Who Could Have Been Bill Gates - A new book says Gates got the rewards due Gary Kildall. What's the real story?". BusinessWeek. Bloomberg Businessweek. Archived from the original on 2012-06-29. Retrieved 2006-11-13.
  19. ^ Eubanks, Gordon (2000-11-08). Morrow, Daniel S. (ed.). "Gordon Eubanks Oral History" (PDF). Computerworld Honors Program International Archives (Interview). Cupertino, CA, USA. Archived from the original (PDF) on 2009-03-26. Retrieved 2006-11-20.
  20. ^ Rolander, Tom (2007-08-08). Scoble, Robert (ed.). "Scoble Show". (Interview). Archived from the original on 2016-11-11. Retrieved 2016-11-11.
  21. ^ a b Rolander, Tom (1994-07-15). "In Memory of GARY A. KILDALL May 19, 1942 -- July 11, 1994". Tom Rolander's Website and Album (Memorial service). Naval Postgraduate School, Monterey, Calif., USA. Archived from the original on 2007-09-27. Retrieved 2006-11-30.
  22. ^ Burton, Kathleen (1985-07-29). "Cash-short Digital Research cuts staff, seeks investors". Computerworld - The Newsweekly for the Computer Community. Computer Industry. Vol. XIX, no. 30. Monterey, California, USA: CW Communications, Inc. p. 72. ISSN 0010-4841. Archived from the original on 2020-02-17. Retrieved 2020-02-17.
  23. ^ a b Allan, Roy A. (2001). A History of the Personal Computer - The People and the Technology (ebook) (1 ed.). Allan Publishing. ISBN 0-9689108-3-1. Retrieved 2016-11-18.
  24. ^ Stark, Craig L. (1986-04-29). "CD ROM Conference: Lured by 600 Megabytes on Disk". PC Magazine: 42. Retrieved 2016-11-19.
  25. ^ "Tom Rolander - Serial entrepreneur and Emergent Farming co-founder". Retrieved 2016-11-11.
  26. ^ Huitt, Robert; Eubanks, Gordon; Rolander, Thomas "Tom" Alan; Laws, David; Michel, Howard E.; Halla, Brian; Wharton, John Harrison; Berg, Brian; Su, Weilian; Kildall, Scott; Kampe, Bill (2014-04-25). Laws, David (ed.). "Legacy of Gary Kildall: The CP/M IEEE Milestone Dedication" (PDF) (video transscription). Pacific Grove, California, USA: Computer History Museum. CHM Reference number: X7170.2014. Archived (PDF) from the original on 2014-12-27. Retrieved 2020-01-19. […] Rolander: […] Gary then started a company, Prometheus Light and Sound, and he was into connected devices within the home. Which is of course what Google and Nest is about at this point, I think the reason for their acquisition. So he was consistently 10, maybe 20 years ahead, of, in many cases, the commercial viability of a lot of those technologies. (33 pages) [2][3]
  27. ^ Cringely, Robert X. (1992). Accidental Empires: How the Boys of Silicon Valley Make Their Millions, Battle Foreign Competition, and Still Can't Get a Date. ISBN 978-0887308550.
  28. ^ Rivlin, Gary (1999). The Plot to Get Bill Gates. Crown Business. ISBN 978-0-8129-3006-1.
  29. ^ a b Shustek, Len (2016-08-02). "In His Own Words: Gary Kildall". Remarkable People. Computer History Museum. Archived from the original on 2016-12-17. Retrieved 2016-11-17.
  30. ^ a b Perry, Tekla S. (2016-08-03). "CP/M Creator Gary Kildall's Memoirs Released as Free Download". IEEE Spectrum. Archived from the original on 2016-11-17. Retrieved 2016-11-17. Later chapters, they indicated, did "not reflect his true self," but rather his struggles with alcoholism, and will remain unpublished.
  31. ^ "A Career Spent in Gates' Shadow -- Computer Pioneer Dies at 52". Retrieved 2022-01-19.
  32. ^ a b Andrews, Paul (1994-07-14). "A Career Spent in Gates' Shadow—Computer Pioneer Dies at 52". The Seattle Times. Archived from the original on 2017-10-13. Retrieved 2017-04-29.
  33. ^ Akass, Clive (2006-08-11). "The man who gave Bill Gates the world - Gary Kildall was one of the founding fathers of the PC but he is remembered now for his greatest mistake". Personal Computer World. Archived from the original on 2008-10-11.
  34. ^ Kirkpatrick, Don (1999-01-12). "comp.os.cpm Frequently Asked Questions (FAQ)". Archived from the original on 2007-09-29. Retrieved 2006-11-20.
  35. ^ Whitely, Peyton (7-16-1994) "Computer Pioneer's Death Probed -- Kildall Called Possible Victim Of Homicide" Seattle Times,
  36. ^ Wharton, John Harrison (1994-08-01). "Gary Kildall, industry pioneer, dead at 52: created first microcomputer languages, disk operating systems". Microprocessor Report. MicroDesign Resources Inc. (MDR). 8 (10). Archived from the original on 2016-11-18. Retrieved 2016-11-18.
  37. ^ "SPA Award to Dr. Gary A. Kildall: 1995 SPA Lifetime Achievement Award Winner". Software Publishers Association (SPA). 1995-03-13. Archived from the original on 2019-12-21. Retrieved 2019-12-21 – via
  38. ^ Kildall, Gary Arlen (June 1975), CP/M 1.1 or 1.2 BIOS and BDOS for Lawrence Livermore Laboratories, An excerpt of the BDOS.PLM file header in the PL/M source code of CP/M 1.1 or CP/M 1.2 for Lawrence Livermore Laboratories (LLL):
    /* C P / M   B A S I C   I / O    S Y S T E M    (B I O S)
                        COPYRIGHT (C) GARY A. KILDALL
                                 JUNE, 1975                   */
    /*  B A S I C   D I S K    O P E R A T I N G   S Y S T E M  (B D O S)
                        COPYRIGHT (C) GARY A. KILDALL
                                JUNE, 1975                          */
  39. ^ Kildall, Gary Arlen (January 1980). "The History of CP/M, The Evolution of an Industry: One Person's Viewpoint". Dr. Dobb's Journal of Computer Calisthenics & Orthodontia. 5 (1): 6–7. #41. Archived from the original on 2016-11-24. Retrieved 2013-06-03. […] The first commercial licensing of CP/M took place in 1975 with contracts between Digital Systems and Omron of America for use in their intelligent terminal, and with Lawrence Livermore Laboratories where CP/M was used to monitor programs in the Octopus network. Little attention was paid to CP/M for about a year. In my spare time, I worked to improve overall facilities […] By this time, CP/M had been adapted for four different controllers. […] In 1976, Glenn Ewing approached me with a problem: Imsai, Incorporated, for whom Glenn consulted, had shipped a large number of disk subsystems with a promise that an operating system would follow. I was somewhat reluctant to adapt CP/M to yet another controller, and thus the notion of a separated Basic I/O System (BIOS) evolved. In principle, the hardware dependent portions of CP/M were concentrated in the BIOS, thus allowing Glenn, or anyone else, to adapt CP/M to the Imsai equipment. Imsai was subsequently licensed to distribute CP/M version 1.3, which eventually evolved into an operating system called IMDOS. […]
  40. ^ Killian, A. Joseph "Joe" (2001). "Gary Kildall's CP/M: Some early CP/M history - 1976-1977". Thomas "Todd" Fischer, IMSAI. Archived from the original on 2012-12-29. Retrieved 2013-06-03. […] When we failed to produce an operating system in a timely manner, Glenn started talking with Gary about CPM […] It took several months of twisting Gary's arm to get Gary to port it to the 8080. The final success came when Glenn talked Gary into just separating the I/O from the rest of it, with Glenn promising to re-write the I/O module for the IMSAI 8080 (which he did). So CPM on the IMSAI was a joint effort between Glenn and Gary. […]
  41. ^ Fraley, Bob; Spicer, Dag (2007-01-26). "Oral History of Joseph Killian, Interviewed by: Bob Fraley, Edited by: Dag Spicer, Recorded: January 26, 2007, Mountain View, California, CHM Reference number: X3879.2007" (PDF). Computer History Museum. Archived from the original (PDF) on 2014-07-14. Retrieved 2013-06-03. Killian: "[…] Intel had hired him a few months earlier to write a control program monitor to run on their little demo system for 8008 and now 8080. […] Glenn knew this and he would be talking with Gary, and he started twisting Gary's arm. He said, "Hey Gary, why can't we run this in this IMSAI?" "The I/O's all different, won't run." But Glenn persists and finally makes a deal with Gary. He says, "Okay Gary, if you split out the I/O, I'll write the BIOS, basic I/O's system," and Glenn named it then. "We'll split it out separately. I'll write that part, as long as you can make a division in the program there." And he got Gary to do that and Glenn put those two pieces together and was running Gary's CP/M on an IMSAI. Glenn let us know that, and it wasn't too much later than Bill was down there making arrangements with Gary Kildall to license CP/M. […] Now that the BIOS is separated out, anybody could write a BIOS for their machine, if it was 8080-based, and run this, so he started selling that separately under the company Digital Research that he formed and did quite well."
  42. ^ Digital Research (1981). XLT86 - 8080 to 8086 Assembly Language Translator - User's Guide (PDF). Pacific Grove, California, USA: Digital Research, Inc. Archived (PDF) from the original on 2016-11-18. Retrieved 2016-11-18.
  43. ^ Sammon, John (2014-04-27). "Computer pioneer honored in Pacific Grove". The Monterey County Herald. Archived from the original on 2014-05-08.

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