“CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/85-based microcomputers by Gary Kildall of Digital Research, Inc. Initially confined to single-tasking on 8-bit processors and no more than 64 kilobytes of memory, later versions of CP/M added multi-user variations and were migrated to 16-bit processors.” – taken from Wikipedia
Want to learn more? Follow the link: http://www.digitalresearch.biz/CPM.HTM
Of particular note is the web site run by Gaby Chaudry: http://www.gaby.de/ecpm.htm
Another excellent resource is the Unofficial CP/M Web Site (link below) which boasts tons of software and source code that is unable to be distributed otherwise.
Have questions? Need help getting started? Just ask! CP/M 2.2 seems to be the most popular for those still working with / on the system. If not on legacy hardware, SIMH and Oracle’s VirtualBox are good PC emulators to start with.
Interested in an open source CP/M clone? Check out the CP/Mish distribution (link below) headed by David Given.