CP/M is an operating system running on different computers with Intel 8080 and compatible CPUs. It was the most popular operating system for micro computers, before the 16 age started successfully with the IBM PC and MS-DOS. Most computer systems running CP/M were based on a Z80 cpu.
It was developed by Gary Kildall of Digital Research, Inc. as a privat project from 1974 on, named Control Program/Monitor. When becoming a commercial software in November 1977 it was renamed to Control Program for Microcomputers.