Editing CP/M (section)

=== Early history ===

[[Gary Kildall]] originally developed CP/M during 1974,<ref name="Shustek_2016"/><ref name="Kildall_1993"/> as an operating system to run on an Intel [[Intellec|Intellec-8]] development system, equipped with a [[Shugart Associates]] 8-inch [[floppy-disk drive]] interfaced via a custom [[floppy-disk controller]].<ref name="Kildall_1980_CPM"/> It was written in Kildall's own [[PL/M]] (''[[Programming Language]] for Microcomputers'').<ref name="Kildall_1975_BDOS"/> Various aspects of CP/M were influenced by the [[TOPS-10]] operating system of the [[DECsystem-10]] [[mainframe computer]], which Kildall had used as a development environment.<ref name="johnson"/><ref name="Dr. Dobb's Journal Apr 1976"/><ref name="Digital Research (Firm)"/>

CP/M supported a wide range of computers based on the [[8080]] and [[Z80]] CPUs.{{r|wilkinson19811019}} An early outside licensee of CP/M was [[Gnat Computers]], an early microcomputer developer out of [[San Diego, California]]. In 1977, the company was granted the license to use CP/M 1.0 for any micro they desired for $90. Within the year, demand for CP/M was so high that Digital Research was able to increase the license to tens of thousands of dollars.<ref>{{cite book | last=Freiberger | first=Paul | author1-link=Paul Freiberger | author2=Michael Swaine | author2-link=Michael Swaine (technical author) | date=2000 | url=https://archive.org/details/fireinvalleymaki00frei_0/ | title= Fire in the Valley: The Making of the Personal Computer| publisher=McGraw-Hill | isbn=0071358927 | via=the Internet Archive | page=175}}</ref>

Under Kildall's direction, the development of CP/M 2.0 was mostly carried out by John Pierce in 1978. [[Kathryn Strutynski]], a friend of Kildall from [[Naval Postgraduate School]] (NPS), became the fourth employee of Digital Research Inc. in early 1979. She started by debugging CP/M 2.0, and later became influential as key developer for CP/M 2.2 and CP/M Plus. Other early developers of the CP/M base included Robert "Bob" Silberstein and David "Dave" K. Brown.<ref name="Brown-Strutynski-Wharton_1983"/><ref name="Strutynski_2010"/>

CP/M originally stood for "Control Program/Monitor",<ref name="CPM.NYT83"/> a name which implies a [[resident monitor]]—a primitive precursor to the operating system. However, during the conversion of CP/M to a commercial product, trademark registration documents filed in November 1977 gave the product's name as "Control Program for Microcomputers".<ref name="Kildall_1993"/> The CP/M name follows a prevailing naming scheme of the time, as in Kildall's PL/M language, and Prime Computer's [[PL/P]] (''Programming Language for Prime''), both suggesting IBM's [[PL/I]]; and IBM's [[CP/CMS]] operating system, which Kildall had used when working at the NPS. This renaming of CP/M was part of a larger effort by Kildall and his wife with business partner, Dorothy McEwen<ref name="Kildall.NYT"/> to convert Kildall's personal project of CP/M and the Intel-contracted PL/M [[compiler]] into a commercial enterprise. The Kildalls intended to establish the Digital Research brand and its product lines as synonymous with "microcomputer" in the consumer's mind, similar to what IBM and Microsoft together later successfully accomplished in making "[[personal computer]]" synonymous with their product offerings. Intergalactic Digital Research, Inc. was later renamed via a corporation change-of-name filing to Digital Research, Inc.<ref name="Kildall.NYT"/>