Computer History Museum Makes Historic CP/M Operating System Source Code Available to the Public

Computer History Museum adds Control Program for Microcomputers as a part of its Software Historical Source Code Series


MOUNTAIN VIEW, Calif., Oct. 1, 2014 (GLOBE NEWSWIRE) -- The Computer History Museum (CHM) announced today that it has made available original source code for early versions of CP/M (Control Program for Microcomputers). Written by Gary Kildall to transfer data from the era's new floppy disk drive storage units to an Intel 8080 microprocessor-based computer, CP/M became the dominant operating system for hobbyist and small business system users in the late 1970s.

"CP/M was unlike most other operating systems in that it consumed very little memory space and could be ported to run on many different personal computers models of the era," said Len Shustek, Museum chairman of the board of trustees. "Combined with its early availability and low cost, this made CP/M a runaway success and laid an important foundation for the personal computer revolution."

The Institute of Electrical and Electronics Engineers (IEEE) has recognized the development of CP/M as an IEEE Milestone in Electrical Engineering and Computing by installing a bronze plaque outside the former headquarters of Kildall's company Digital Research, Inc. in Pacific Grove, California. To mark the 40th anniversary of the prototype demonstration in Kildall's backyard toolshed in the fall of 1974, the Computer History Museum is pleased to make available, for non-commercial use, the source code of several of the early releases of CP/M.

The Museum is releasing scanned printer listings and/or machine-readable source code for four early versions of CP/M dating from 1975 to 1979. The first is the earliest source code for CP/M the Museum has been able to locate, dating from before there were official version numbers. It was used at Lawrence Livermore National Laboratory for its Octopus network system. Next is Version 1.3, from 1976, which was the first release to include the BIOS (Basic Input Output System) code that made it easy to modify the software for different computers; this version also includes an amazing 48-page reverse-engineered source code listing with a hand-annotated disassembly of the object code. Lastly, the Museum is releasing Versions 1.4 and 2.0, which allowed compilation and assembly on personal computers and considerably expanded and generalized access to disks.

"The Museum thinks preserving historic source code like these programs is key to understanding how software has evolved from its primitive roots to become a crucial part of our civilization," said Shustek.

For a blog posting surrounding the release of this source code, please visit:

For other releases in the Museum's historic source code series, please see:


IBM APL- Apple

MacPaint and QuickDraw –

Adobe Photoshop-

Microsoft Word for Windows Version 1.1-


About the Computer History Museum

The Computer History Museum in Mountain View, California, is a nonprofit organization with a four-decade history as the world's leading institution exploring the history of computing and its ongoing impact on society. The Museum is dedicated to the preservation and celebration of computer history and is home to the largest international collection of computing artifacts in the world, encompassing computer hardware, software, documentation, ephemera, photographs, and moving images. The Museum brings computer history to life through large-scale exhibits, an acclaimed speaker series, a dynamic website, docent-led tours, and an award-winning education program.

The Museum's signature exhibition is "Revolution: The First 2000 Years of Computing," described by USA Today as "the Valley's answer to the Smithsonian." Other current exhibits include "Charles Babbage's Difference Engine No. 2," "IBM 1401 and PDP-1 Demo Labs", and "Where To? The History of Autonomous Vehicles."

For more information and updates, call (650) 810-1059, visit, check us out on Facebook, follow @computerhistory on Twitter, and the Museum blog @chm.


Contact Data