Jack B. Dennis is a computer science educator and researcher who is best known for his pioneering work in computer timesharing and dataflow technology.
Background
Jack Bonnell Dennis was born on October 13, 1931, in Elizabeth, New Jersey, to Wolcott Dennis and Nereide Bonnell. His father was from Seattle and was employed at the Air Reduction Company in New Jersey. His duties there included “boiling air,” an oxygen extraction process where air is cooled to a liquid form, then gradually heated to “boil off” the nitrogen, leaving pure liquid oxygen. Dennis’s mother grew up in Elizabeth, New Jersey, and became a teacher. When Jack was one year old, the family moved to Darien, Connecticut.
Education
Dennis graduated from the Massachusetts Institute of Technology (MIT) as Bachelor of Science (1953), Master of Science (1954), and Doctor of Science (1958).
He became a full professor at MIT in 1969. He was involved in early work on time-sharing through the PDP-1 which his research group owned at MIT. That hardware later became famous in computer science history as the machine on which hacker culture started.
He also sponsored the MIT student-run Tech Model Railroad Club in its early years, where the hacker culture is said to have taken root before spreading to the MIT Artificial Intelligence Lab. Later, he was one of the founding members of the Multics project, to which he contributed one of its most important concepts, the single-level memory. Multics, though not particularly commercially successful in itself, was an inspiration for Ken Thompson to develop Unix.
The latter part of his career was devoted to non-von Neumann models of computation, architecture, and languages. He wanted to free programs from the concept of a program counter. So adopting the concept of "single-assignment," he along with his students and others developed data flow concepts which executed instructions as soon as data became available (this specific model came to be called "static" in contrast to Arvind's later "dynamic").
He retired from MIT in 1987 to do independent projects and consulting. He also developed the VAL static data-flow language which in turn inspired the compiler for the SISAL programming language.
Achievements
Dennis was one of the founders of the pioneering Multics project. His most important contribution to this project was the concept of the single-level memory.
He received numerous awards for his contribution (IEEE John von Neumann Medal, Association for Computing Machinery (ACM) Special Interest Group on Operating Systems (SIGOPS) Hall of Fame, Member of the National Academy of Engineering (NAE)).
Membership
He was a visiting scientist at NASA's Research Institute for Advanced Computer Science (RIACS). In 1994 he was inducted as a Fellow of the Association for Computing Machinery. He was elected to the National Academy of Engineering in 2009.
Dennis was also a member of the historic Tech Model Railroad Club, which incubated much of the early slang and traditions of hacking.
Connections
He was married to Teresa Smith, who was a system engineer.
