Gary Kildall

Gary Kildall (1942-1994) was an American computer scientist and entrepreneur. He developed the CP/M operating system, which became one of the most popular operating systems for early microcomputers. Kildall's work laid the foundation for modern operating systems, and he played a key role in the early development of the personal computer industry.

Introduced the theory of data-flow analysis in optimizing compilers (global expression optimization, Kildall's method). Worked on instruction set emulators (INTERP), found an innovative software relocation method (page boundary relocation), and laid the foundation to the concepts of binary recompilation (XLT86). Developed the first high-level programming language and compiler for microcomputers (PL/M) and the first mainstream operating system for microcomputers (CP/M). Invented the concept of a hardware abstraction layer called the BIOS, with both conceptually laying the foundation to all DOS-based operating systems on personal computers. Worked on diskette track buffering schemes, read-ahead algorithms, virtual disk drives, and file system caching. Developed the first computer interface for video disks and pioneered CD-ROM file systems, introducing the first encyclopedia for computers (The Electronic Encyclopedia). Pioneered a modular PBX communication system integrating land-lines with mobile phones (Intelliphone) and to remotely connect with home appliances.

Gary Arlen Kildall was an American computer scientist and microcomputer entrepreneur. During the 1970s, Kildall created the operating system CP/M among other operating systems and programming tools, and subsequently founded Digital Research, Inc. to market and sell his software products. He is considered a pioneer of the personal computer revolution.

• He is considered a pioneer of the personal computer revolution.
• In 1974 in Pacific Grove, California, Kildall demonstrated the first working prototype of CP/M, which would later become the dominant operating system for microcomputers for a time.