Peter James Denning (born January 6, 1942) is an American computer scientist and writer. He is best known for pioneering work in virtual memory, especially for inventing the working-set model for program behavior, which addressed thrashing in operating systems and became the reference standard for all memory management policies. He is also known for his works on principles of operating systems, operational analysis of queueing network systems, design and implementation of CSNET, the ACM digital library, codifying the great principles of computing, and most recently for the book The Innovator's Way, on innovation as a set of learnable practices. Education and early life Denning was born January 6, 1942, in Queens, NY, and raised in Darien, CT. He took an early interest in science, pursuing astronomy, botany, radio, and electronics while in grade school. At Fairfield Prep, he submitted home designed computers to the science fair in 1958, 1959, and 1960. The second computer, which solved linear equations using pinball machine parts, won the grand prize. He attended Manhattan College for a Bachelor in EE (1964) and then MIT for a PhD (1968). At MIT he was part of Project MAC and contributed to the design of Multics. His PhD thesis, "Resource allocation in multiprocess computer systems", introduced seminal ideas in working sets, locality, thrashing, and system balance. Career and research At Princeton University from 1968 to 1972, he wrote his classic book, Operating Systems Principles, with E G Coffman. He collaborated with Alfred Aho and Jeffrey Ullman on optimality proofs for paging algorithms and on a simple proof that compilers based on precedence parsing do not need to backtrack. 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. He co-founded CSNET. He became department head in 1979 and completed another book on computational models, Machines, Languages, and Computation, with Jack Dennis and Joe Qualitz. At NASA Ames from 1983 to 1991 he founded the Research Institute for Advanced Computer Science (RIACS) and turned it into one of the first centers for interdisciplinary research in computational and space science. 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. The Center was a pioneer in web-based learning. He created a design course for engineers,