The first Operating System for microcomputers

Not a lot of people recognizes the name of Gary Kildall, but there is a lot of history behind the name of the creator of the first known computer operating system. Gary was born on May 19, 1942, in Seattle, Washington where he grew up and obtained all his degrees in the University of Washington.


He attended to the University of Washington hoping to graduate as a mathematics teacher and where started being interested in Computer Technology. After receiving his degree, he taught at the Naval Postgraduate School (NPS) in California as part of a draft obligation, what brought him to be within an hour of drive to Silicon Valley. He heard about and bought the first commercially available processor, the Intel 4004 and began writing experimental programs for it and to learn more about it he became a consultant for Intel on his days off.


After returning to the University of Washington to finish his doctorate in Computer Science in 1972 he published a paper that introduced the theory of data-flow analysis which is currently used in Optimizing Compilers (also known as the Kildall’s method).


Thanks to his continuous work with computer processors (8008,8080) lent to him by Intel, he developed the first high-level programming language known as PL/M. He also wrote an instruction set simulator named INTERP/80 for the 8080 and in 1974 he created CP/M (Control Program/Monitor) considered by many as the first significant Operating System for microcomputers.


Later, in 1975, Kildall introduced the term BIOS (Basic Input/Output System) describing the machine-specific part of CP/M loaded during boot time that interfaces directly with the hardware; and BDOS (Basic Disk Operating System) that provided access to such operations as opening a file, output to the console, or printing.


Although the discussion about the first Operating System could lead to some controversy it is truth that Gary Kildall’s contribution to the Computer Science was significant and very important to the modern computer industry. And you, what was the first Operating System you got to use?


By Jose Lopez


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