An operating system written by Gary Kildall at Intel. Intel didn't see a need for it, so Kildall founded Digital Research and sold the OS as CP/M. CP/M was geared towards machines based on the Intel 8080. Later Digital Research also created CP/M-86 (for use on Intel 8086/8088 machines) and CP/M-68k (for use on 68000 based machines). Neither were as popular as CP/M-80. CP/M-80 was the most popular OS for micro-computers until the rise of PC-DOS.