As a professor at MIT, Dennis was influential in the work of student
Alan Kotok and fellow professors
Marvin Minsky and
John McCarthy. Dennis was one of the founders of the
Multics project. His most important contribution to the project was the concept of the
single-level memory. Multics was not fully successful as a commercial project, but it was important because it influenced the design of many other computer
operating systems, most importantly the direct inspiration for
Ken Thompson (who also worked on the project) to design the first incarnation of
Unix. In recognition of his work on the Multics project, Dennis was elected as IEEE Fellow. Dennis' research at the MIT focused in Computer Theory and Computer Systems, specifically: • Theoretical Models for Computation • Computation Structures • Structure of Computer Systems • Semantic Theory for Computer Systems • Semantics of Parallel Computation • Computer System Architecture Dennis also worked as an independent consultant and research scientist on projects related to parallel computer hardware and software since his retirement from MIT in 1987. He worked with the NASA Research Institute for Advanced Computer Science as visiting scientist, with the Architecture Group of Carlstedt Elektronik (Gothenburg, Sweden), and with Acorn Networks, Inc., as Chief Scientist. A great part of Dennis' career was devoted to non-
von Neumann models of computation, architecture, and languages, where programs are not attached to a program counter. Along with his students, Dennis adopted the concepts of
single assignment and
dataflow, in which instructions are executed as soon as data are available (this specific model is called "static" in contrast to
Arvind's "dynamic"). In 2009, Dennis was elected a member of the
National Academy of Engineering for contributions to sharing and protection in computer systems and parallel architectures based on data flow principles. ==Death==