IEEE Milestone: CP/M Microcomputer Operating System


Milestone: CP/M Microcomputer Operating System, 1974

Dedication Date: April 25, 2014

Control Program for Microcomputers, CP/M, 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.

Before 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.”


About the Inventor:

From: NPS website

In the early 1970s, before Windows, MacOS, or even MS-DOS, Gary Kildall created CP/M, the Computer Program for Microcomputers, which enabled Intel’s 8080 processor to communicate with an external disk drive. It would prove to be the world’s first computer disk operating system, and became a critical step forward in making computers personal.

He developed the world’s first high-level microprocessor programming language, PL/M, the foundation on which his CP/M operating system was built.

Kildall also pioneered the first successful Basic Input/Output System, or BIOS, a type of firmware used to perform hardware initialization during the computer’s booting process. BIOS routines work in the background of every computer function as users move freely between programs and hardware devices.

Kildall was a true visionary, a technical savant with equal skill in seeing computing through the eyes of ordinary users. He foresaw users’ desires to multitask, to use windows, and to interact with the machine via a menu-driven graphical user interface, years before these became industry norms.

He is also recognized for leading the development of an optical storage medium, paving the way for what became the standard CD-ROM.

The Naval Postgraduate School (NPS) Department of Computer Science, in Monterey, California, took a step forward in recognizing Kildall’s broad contributions to personal computing, dedicating the Dr. Gary A. Kildall Memorial Conference Room in the university’s Glasgow Hall in April 2017.


“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.”

801 Lighthouse Avenue
Pacific Grove, CA
Note: the plaque is mounted at the edge of the
public sidewalk adjacent to a retaining wall
surrounding the property.