CP/M



"The microcomputer software standard."

CP/M (Control Program for Microcomputers) is an operating system produced by Digital Research. It was perhaps the most popular system in the early days of home computing. However, its luck ended when IBM decided to make their own machine. While IBM had intended to license it, negotiations failed, and instead they went for Microsoft's suspiciously similar MS-DOS. So the market for CP/M quickly waned.