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Docket #:2013-23

This Proposal has been approved, and is now a Milestone

To the proposer’s knowledge, is this achievement subject to litigation?

Is the achievement you are proposing more than 25 years old? Yes

Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes

Did the achievement provide a meaningful benefit for humanity? Yes

Was it of at least regional importance? Yes

Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes

Has an IEEE Organizational Unit agreed to arrange the dedication ceremony? Yes

Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes

Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes

Year or range of years in which the achievement occurred:


Title of the proposed milestone:

The CP/M Microcomputer Operating System, 1974

Plaque citation summarizing the achievement and its significance:

Dr. Gary A. Kildall demonstrated the first working prototype of CP/M (Control Program for Microcomputers) in Pacific Grove in 1974. Together with his invention of the BIOS (Basic Input Output System), Kildall’s operating system allowed a microprocessor-based computer to communicate with a disk drive storage unit and provided an important foundation for the personal computer revolution.

200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.

IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.

In what IEEE section(s) does it reside?

Santa Clara Valley Section

IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:

IEEE Organizational Unit(s) paying for milestone plaque(s):

Unit: Santa Clara Valley Section
Senior Officer Name: {{{Senior officer name}}}

IEEE Organizational Unit(s) arranging the dedication ceremony:

Unit: Santa Clara Valley Section
Senior Officer Name: {{{Senior officer name}}}

IEEE section(s) monitoring the plaque(s):

IEEE Section: Santa Clara Valley Section
IEEE Section Chair name: {{{Section chair name}}}

Milestone proposer(s):

Proposer name: Richard Ahrons
Proposer email: Proposer's email masked to public

Proposer name: David Laws
Proposer email: Proposer's email masked to public

Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.

Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):

801 Lighthouse Avenue, Pacific Grove, CA 93950 GPS: 36.623549,-121.923315

Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.

Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. Gary Kildall (1942 – 1994) developed the first working prototype of the CP/M operating system in his home on Bayview Avenue, Pacific Grove in 1973 and 1974. In 1976 he incorporated Digital Research, Inc. (DRI) to commercialize the program and released version 1.3. The intended site for the plaque, a two-story Victorian residence at the corner of Lighthouse Avenue and Willow Street, served as the DRI headquarters building from 1978 to 1991. This was the site of a contentious 1980 IBM visit to negotiate a licensing agreement to offer CP/M as the operating system for the company’s upcoming personal computer.

Are the original buildings extant?

Yes. The building has returned to use as a private residence.

Details of the plaque mounting:

The plaque will be mounted at the edge of the public sidewalk adjacent to a retaining wall surrounding the property.

How is the site protected/secured, and in what ways is it accessible to the public?

The plaque will be mounted flush with the surface of the sidewalk and securely embedded in the concrete.

Who is the present owner of the site(s)?

City of Pacific Grove. The Director of Public Works/Community Development has given verbal permission to place the plaque on city property and is preparing a quotation for the cost of using the city resources to install the plaque. The city bureaucracy is unsure who is responsible for preparing such a letter, but the City Manager and the Mayor both support the project and assure me that it will not be a problem.

What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include justification here. (see section 6 of Milestone Guidelines)

CP/M (Control Program for Microcomputers) was the first commercial operating system to allow a microprocessor-based computer to interface to a disk drive storage unit. CP/M played an important role in stimulating the hobbyist personal computer movement of the 1970s. Its ability to support software programs on a wide variety of hardware configurations enabled early use of microcomputer systems from many different manufacturers in business and scientific applications. Microsoft DOS, as licensed to IBM for the original PC, was written to emulate the "look and feel" of CP/M. Thus CP/M was the forerunner of the operating systems that now power the majority of the world’s computers and led to the personal computing revolution.

What obstacles (technical, political, geographic) needed to be overcome?

The major challenge that Kildall had to overcome in the development of CP/M was the design and debugging of the “complex electronics ... to make the diskette drive find certain locations and transfer data back and forth”. The following recollections are abstracted from pages 53 - 55 of "Computer Connections", an unpublished autobiography that he wrote and distributed to friends and family in 1994. "Memorex ... had come up with the new "floppy disk" to replace IBM punched cards. I stared at that damn diskette drive for hours on end ... trying to figure a way to make it fly. I tried to build a diskette controller … but I, being mainly hardware inept … couldn’t get my controller to work. So I built an operting (sic) system program ... I called it CP/M [but] I just couldn't figure out how to make that damn disk drive work. Out of frustration, I called my good friend from the University of Washington, John Torode. He designed a neat little microcontroller and after a few months of testing that microcontroller started to work. We loaded my CP/M program from paper tape to the diskette and "booted" CP/M from the diskette, and up came the prompt *. This may have been one of the most exciting days of my life."

What features set this work apart from similar achievements?

Before Kildall’s development of CP/M, computer manufacturers provided proprietary applications software that worked only on their own hardware. All programs had to be written from the ground up to operate on each unique machine configuration. CP/M was initially designed to work on the Intel 8080 microprocessor and allowed computer systems built by any manufacturer who used that chip to run applications programs written by third-party suppliers. CP/M introduced a new element of competition into the computer marketplace that stimulated rapid growth in the use of low-cost systems in business, industry and academia and eventually in the home. According to Kildall, “CP/M was an instant success. By 1980, DRI had sold millions of copies of CP/M to manufacturers and end-users.”

Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.

Kildall’s autobiography “Computer Connections” notes on page 55 that he solicited the help of John Torode in 1974. He gives no specific date but recalls that “This was in the late afternoon and … John and I retired to have a Chinese dinner in Pacific Grove”. E-mail correspondence from John, dated June 24, 2013, places the time frame as follows: “My wife and I concur that it was probably after our wedding on June 22 1974, but before we moved to Chicago (she worked for Bell Labs) in the fall”.

Kildall’s own public account of the history of CP/M was published in Dr Dobbs Journal in 1980: THE EVOLUTION OF AN INDUSTRY: ONE PERSON'S VIEWPOINT, "Dr. Dobb's Journal of Computer Calisthenics & Orthodontia", Vol.5, No.1, (January 1980) (number 41), page 6-7 [1]

Numerous popular accounts of the history of CP/M have been published in newspaper and magazine articles and in books, as well as online. Most of them focus on the fictitious story that DRI lost out to Microsoft on the IBM PC operating system decision because Kildall had taken the day off to go flying. Kildall refutes this story in “Computer Connections” but it is probably most eloquently recounted in Harold Evans’ book on U.S. pioneers and innovators “They Made America.” Harold Evans, “They Made America: Two Centuries of Innovators from the Steam Engine to the Search Engine” (2004) ISBN 0-316-27766-5 [2]

Steve Ham and Jay Greene, “The Man Who Could Have Been Bill Gates,” Bloomberg Business Week, 24 October 2004. [3]

Online only sources

CP/M and Digital Research Inc. (DRI) Web pages [4]

CP/M [5]

Gary Kildall Special (Video) [6]

A Short History of CP/M [7]

Gordon Eubanks Oral History (Computerworld 2000) [8]

Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to Please see the Milestone Program Guidelines for more information.

Numerous original documents, images, personal reminiscences, and videos contributed by employees are posted on the Digital Research Inc. page of the IT Corporate Histories Collection website hosted by the Computer History Museum at:

Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).

Please recommend reviewers by emailing their names and email addresses to Please include the docket number and brief title of your proposal in the subject line of all emails.