At Purdue University (1972–1983) he supervised numerous PhD theses validating locality-based theories of memory management and extending the new mathematics of operational analysis of queueing networks.
At George Mason University from 1991 to 2002 he headed the Computer Science Department, was an associate dean and vice provost, and founded the Center for the New Engineer.
He created a design course for engineers, called Sense 21, which was the basis of his project to understand innovation as a skill.
[6] At Naval Postgraduate School since 2002, he heads the Computer Science Department, and directs the Cebrowski Institute for Innovation and Information Superiority.
From 1985 to 1993 he wrote 47 columns on "The Science of Computing" for American Scientist magazine,[10] focusing on scientific principles from across the field.
Beginning in 2001 he has written quarterly "IT Profession" columns[11] for Communications of the ACM, focusing on principles of value to practicing professionals.
[12] In 1966 he proposed the working set as a dynamic measure of memory demand, and explained why it functioned using the locality idea introduced by Les Belady of IBM.
In the early 1970s he collaborated with Ed Coffman Jr., on Operating Systems Theory, which became a classic textbook used in graduate courses and stayed in print until 1995.
The operational framework explained why computer performance models work so well, even though violating the traditional stochastic Markovian assumptions.
In the early 1970s he led a task force that designed the first core course on operating systems (OS) principles.
OS became the first CS core course which was not focused on pure mathematical theory, though it still used math freely as needed.
In the mid-1980s he led a joint ACM/IEEE committee that described computing as a discipline with nine core functional areas and three cognitive processes, the basis of ACM Curriculum 1991.
In 2009, ACM's SIGCSE (Special Interest Group on Computer Science Education) recognized his contributions with its lifetime service award.