Gary Kildall: The CP/M Genius Who Lost the IBM Deal to Bill Gates

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Gary Kildall wrote the first practical operating system for personal computers, yet he is remembered mostly for a rumor that he went flying instead of meeting IBM. Born in Seattle in 1942 to a family that ran a seamanship school, he planned to teach high school math. Instead he taught at the Naval Postgraduate School in Monterey, earned a doctorate in 1972, and began experimenting with early Intel chips. In 1973 he created PL/M, the first high-level language for microprocessors, and CP/M, which let a microcomputer work with a floppy disk drive.

This episode corrects the legend. Intel passed on CP/M, so Kildall and his wife Dorothy founded Digital Research, and by 1981 the system ran on 3,000 computer models. When IBM came calling in 1980, he was flying to deliver software, and talks stalled over a strict nondisclosure agreement and a flat fee. Microsoft bought a CP/M clone called 86-DOS and the rest followed. The episode also covers his later inventions and his death in 1994 at age 52.

• Kildall invented the BIOS, a layer of code that absorbed each machine's hardware quirks so one program could run on many different computers.
• He found that the first 26 system calls in PC DOS were virtually identical to CP/M, but his attorney warned that software law was too weak to guarantee a win.
• IBM agreed to offer CP/M-86 alongside PC DOS, then priced it at 240 dollars against 40 dollars for the Microsoft system.
• He went on to build the GEM graphical interface in 1985, put Grolier's encyclopedia on a CD-ROM, and sold animation technology to Pixar.
• In 1992 the University of Washington invited him to its computer science anniversary as a guest while Bill Gates gave the keynote, prompting his unpublished memoir Computer Connections.