1974年、キルドールと彼の妻ドロシーは、CP/Mの開発の継続と販売のためにIntergalactic Digital Research（後にデジタルリサーチに改称）を設立し、ホビイスト向けの雑誌にCP/Mの広告を出した。デジタルリサーチは、Altair 8800の人気のあった互換機であるIMSAI 8080に対しCP/Mをライセンスした。多くのメーカーがCP/Mのライセンスを受けたため、CP/Mはデファクト・スタンダードとなり、多くのハードウェア・バリエーションに対応しなければならなくなった。それに対応するため、キルドールはBIOSの概念を創始した。BIOSはハードウェアに格納された一連の単純なプログラムで、それによりCP/M自体を修正することなく異なるシステム上で動作できるようにした[3]。
キルドールは、デジタルリサーチの外でもコンピュータ関連のプロジェクトを進めた。1983年から始まった、パーソナル・コンピューティングの傾向を取り上げる公共放送のテレビ番組『コンピュータ・クロニクルズ（英語版）』の司会者の一人となった。KnowledgeSetという別の会社を起業し、光ディスク技術をコンピュータでの使用に適応させた。1985年に、世界初のコンピュータ百科事典であるグロリアの『アカデミックアメリカン百科事典（英語版）』を公開した[10]。キルドールの最後の事業はテキサス州オースティンに拠点を置くPrometheus Light and Soundで、固定電話と携帯電話を統合した家庭用PBXシステムを開発した[3]。
ハロルド・エヴァンズ（英語版）は2004年の著書『They Made America』のキルドールについての章の情報源として、彼の回顧録を使用した。そして、マイクロソフトがキルドールから彼の発明を奪ったと結論づけた[12]。IBM PCプロジェクトからのIBM出身者は、この本の説明に異議を唱えた。マイクロソフトはそれを「一方的で不正確である」と述べた[14]。
1994年7月8日、キルドールはカリフォルニア州モントレーのバイカーバー（英語版）で転落して頭部を打った[19]。怪我の正確な状況は不明なままであるが、彼は晩年アルコール中毒で苦しんでいた[20][21]。負傷の理由は、椅子から落ちたとか、階段で転んだ、または何者かに襲われたといった説がある[11]。3日後の7月11日にモントレー半島（英語版）の公共病院で亡くなった。検死官は、死因を頭部への打撲と特定した。彼が心臓発作を経験していたという証拠もあったが、死因とは確証的に決定されなかった[18][22][23]。北シアトルのEvergreen-Washelli Memorial Parkに埋葬されている。
^ abcEvans, Harold; Buckland, Gail; Lefer, David (2004). They Made America: From the Steam Engine to the Search Engine: Two Centuries of Innovators. Little, Brown and Co. ISBN0-316-27766-5
^Manes, Stephen; Andrews, Paul (1992). Gates: How Microsoft's Mogul Reinvented an Industry—and Made Himself the Richest Man in America. Doubleday. ISBN0-671-88074-8
^Kildall, Gary A. (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 */
[...]
"
^Kildall, Gary A. (January 1980). “The History of CP/M, The Evolution of an Industry: One Person's Viewpoint”. Dr. Dobb's Journal of Computer Calisthenics & Orthodontia. pp. 6–7. 2013年6月3日閲覧。 “[...] 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. [...]”
^Killian, A. Joseph "Joe" (2001年). “Gary Kildall's CP/M: Some early CP/M history - 1976-1977”. Thomas "Todd" Fischer, IMSAI. 2013年6月3日閲覧。 “[...] When we failed to produce an operating system in a timely manner, Glenn started talking with Gary about CPM, which Gary had written for Intel under contract. 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. [...]”
^“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,”. Computer History Museum (2007年1月26日). 2013年6月3日閲覧。 “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（英語版） 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."”
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Akass, Clive. Interview: Eubanks, Gordon, Former Student & CEO of Oblix, Inc., Recollections of Gary Kildall. DigitalResearch.biz.
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Rolander, Tom (July 15, 1994). Eulogy. Tom Rolander's Website and Album.
Markoff, John. "Gary Kildall, 52, Crucial Player In Computer Development, Dies", New York Times, July 13, 1994, p. D19.
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Swaine, Michael (April 1, 1997). "Gary Kildall and Collegial Entrepreneurship". Dr. Dobb's Journal.
Kirkpatrick, Don (January 12, 1999). comp.os.cpm Frequently Asked Questions (FAQ).
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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 Co. ISBN 0-316-27766-5.
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