CP/M was 5K and it gave you no more and no less than what an operating system should do.
–Alan Cooper, personal-computer software pioneer
The first operating system to qualify as a standard in the developing microcomputer industry actually appeared before the Altair itself. CP/M was not the result of a carefully planned project involving years of research by dozens of software specialists. Like most of the early significant programs, it originated out of one person’s initiative.
In mid-1972, Gary Kildall came across an advertisement on a bulletin board that said “MICROCOMPUTER $25.” The item advertised, the Intel 4004, was actually a microprocessor, arguably the first in the world, but it still sounded ...