Peter J. Denning


Peter James Denning (born January 6, 1942) is an American
computer scientist A computer scientist is a person who has acquired the knowledge of computer science, the study of the theoretical foundations of information and computation and their application. Computer scientists typically work on the theoretical side of c ...

computer scientist
and writer. He is best known for pioneering work in
virtual memory In computing, virtual memory, or virtual storage is a Memory management (operating systems), memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "cre ...

virtual memory
, especially for inventing the
working-set model Working set is a concept in computer science which defines the amount of memory that a process (computing), process requires in a given time interval. Definition Peter_J._Denning, Peter Denning (1968) defines "the working set of information W(t, \ ...
program Program, programme, programmer, or programming may refer to: Business and management * Program management, the process of managing several related projects * Time management * Program, a part of planning Arts and entertainment Audio * Program ...
behavior, which addressed thrashing in
operating system An operating system (OS) is system software System software is software designed to provide a platform for other software. Examples of system software include operating systems (OS) like macOS, Linux, Android (operating system), Android and Mi ...

operating system
s and became the reference standard for all
memory management Memory management is a form of resource management In organizational studies Organizational studies is "the examination of how individuals construct organizational structures, processes, and practices and how these, in turn, shape social relat ...
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 Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and software. It has sci ...

, 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 Astronomy (from el, ἀστρονομία, literally meaning the science that studies the laws of the stars) is a natural science that studies astronomical object, celestial objects and celestial event, phenomena. It uses mathematics, phys ...
botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device ...

, and
electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons The electron is a subatomic particle In physical sciences, subatomic particles are smaller than ...
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 In mathematics Mathematics (from Greek: ) includes the study of such topics as numbers (arithmetic and number theory), formulas and related structures (algebra), shapes and spaces in which they are contained (geometry), and quantities and ...
pinball Pinball is an arcade entertainment machine in which a ball careens around the machine's interior, hitting various lights, bumpers, ramps, and other targets depending on its design. The game's object is to score as many points as possible by hit ...
machine parts, won the grand prize. He attended
Manhattan College Manhattan College is a private university, private, Catholic school, Catholic, Liberal arts colleges in the United States, liberal arts college in the Bronx in New York City. After originally being established in 1853 by the Institute of the B ...
for a
Bachelor A bachelor is a man who is not and has never been married.Bachelors are, in Pitt Pitt most commonly refers to: *The University of Pittsburgh, commonly known as Pitt, a university located in Pittsburgh, Pennsylvania, United States **Pitt Panthe ...
(1964) and then
MIT Massachusetts Institute of Technology (MIT) is a private land-grant research university A research university is a university A university ( la, universitas, 'a whole') is an educational institution, institution of higher education, hi ...

for a
PhD A Doctor of Philosophy (PhD, Ph.D., or DPhil; Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known a ...
(1968). At MIT he was part of
Project MAC MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) is a research institute at the Massachusetts Institute of Technology (MIT) formed by the 2003 merger of the Laboratory for Computer Science (LCS) and the Artificial Intelligence ...
and contributed to the design of
Multics Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experi ...

. His PhD
thesis A thesis, or dissertation (abbreviated diss.), is a document submitted in support of candidature for an academic degree An academic degree is a qualification awarded to students upon successful completion of a course of study in higher ed ...
, "Resource allocation in multiprocess computer systems", introduced seminal ideas in working sets, locality, thrashing, and system balance.

Career and research

Princeton University Princeton University is a private Private or privates may refer to: Music * "In Private "In Private" was the third single in a row to be a charting success for United Kingdom, British singer Dusty Springfield, after an absence of nearly tw ...

Princeton University
from 1968 to 1972, he wrote his classic book, ''Operating Systems Principles'', with E G Coffman. He collaborated with
Alfred Aho Alfred Vaino Aho (born August 9, 1941) is a Canadian computer scientist A computer scientist is a person who has acquired the knowledge of computer science Computer science deals with the theoretical foundations of information, algorit ...
Jeffrey Ullman Jeffrey David Ullman (born November 22, 1942) is an American computer scientist A computer scientist is a person who has acquired the knowledge of computer science, the study of the theoretical foundations of information and computation and ...
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 Purdue University is a in , and the flagship campus of the . The university was founded in 1869 after businessman donated land and money to establish a college of science, technology, and agriculture in his name. The first classes were hel ...
(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 The Computer Science Network (CSNET) was a computer network that began operation in 1981 in the United States. Its purpose was to extend networking benefits, for computer science Computer science deals with the theoretical foundations of info ...
. 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, called ''Sense 21'', which was the basis of his project to understand innovation as a skill. He created a course on Core of Information, Technology the basis his Great Principles of Computing project. At Naval Postgraduate School since 2002 he heads the Computer Science Department, directs the Cebrowski Institute for Innovation and Information Superiority. He chaired the faculty council. Denning served continuously as a volunteer in Association for Computing Machinery (ACM) since 1967. In that time he served as president, vice president, three board chairs, Member-at-Large, Editor of ACM Computing Surveys, and Editor of the monthly Communications of the ACM, ACM Communications. He received seven ACM awards for service, technical contribution, and education. ACM presented him with a special award in June 2007 recognizing 40 years of continuous service. Denning has received 26 awards for service and technical contributions. These include one quality customer service award, three professional society fellowships, three honorary degrees, six awards for technical contribution, six for distinguished service, and seven for education. Denning's career has been a search for fundamental principles in subfields of computing. He writes prolifically. From 1980 to 1982 he wrote 24 columns as ACM President, focusing on technical and political issues of the field. From 1985 to 1993 he wrote 47 columns on "The Science of Computing" for American Scientist magazine, focusing on scientific principles from across the field. Beginning in 2001 he has written quarterly "IT Profession" columns for Communications of the ACM, focusing on principles of value to practicing professionals.

Virtual memory

In 1970 he published a classic paper that displayed a scientific framework for virtual memory and the validating scientific evidence, putting to rest a controversy over virtual memory stability and performance. In 1966 he proposed the working set as a dynamic measure of memory demand and explained why it worked using the locality idea introduced by Les Belady of IBM. His working set paper became a classic. It received an ACM Best paper award in 1968 and a SIGOPS Hall of Fame Award in 2005.

Operating system principles

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. That book helped to erase doubts that the OS field could be approached as a science. In the middle 1970s he collaborated with Jeffrey Buzen on operational analysis, extending Buzen's basic operational laws to deal with all queueing networks. The operational framework explained why computer performance models work so well, even though violating the traditional stochastic Markovian assumptions. It has become the preferred method for teaching performance prediction in computing courses. In the early 1980s, he was one of the four founding Principal investigators of CSNET, Computer Science Network, sponsored by the National Science Foundation The other three were Dave Farber, Larry Landweber, and Tony Hearn. They led the development of a fully self-supporting CS community network that by 1986 included 165 sites and 50,000 users. CSNET was the key transitional stepping stone from the original ARPANET to the NSFNET and then the Internet. In 2009, the Internet Society awarded CSNET its prestigious Jon Postel award, recognizing its key role in bridging from the ARPANET to NSFNET. He led the ACM Digital Library project 1992-97, which went live in 1997. The Association for Computing Machinery became the first professional society to offer a fully searchable library of everything it ever published.

Great Principles of Computing

In 1999, he expanded the search for fundamental principles to cover all of computing. The discovery of natural information processes in biology, physics, economics, materials, and other fields convinced him that the basic definitions of computation had to be modified to encompass natural information processes as well as artificial. He and his team have produced a draft framework. The Great Principles framework revealed that "innovating" is a core practice of computing. Unable to find anyone who understood how to teach the skill of innovating, he joined with Bob Dunham and identified eight foundational practices of innovation. They published ''The Innovator's Way'', a book laying the eight essential practices of successful innovation.

Computing education

Denning has been a major influence in computing education. In the early 1970s he led a task force that designed the first core course on operating systems (OS) principles. OS became the first non-math CS core course. In the mid 1980s he led a joint ACM/IEEE committee that described computing as a discipline with nine functional areas and three cognitive processes, the basis of ACM Curriculum 1991. In the 1990s he set out on a quest to codify the great principles of computing. He maintains that computing is a science both of natural and artificial information processes. NSF designated him a Distinguished Education Fellow in 2007 to launch a movement to use the Great Principles framework for innovations in education and research. In 2009, ACM's SIGCSE (Special Interest Group on Computer Science Education) recognized his contributions with its lifetime service award.


Denning is an inveterate punster who frequently uses humor to get points across. Examples: * April Fool special section (when he was editor), Communications of the ACM, ACM Communications (April 1984).
On Active and Passive Writing
a treatise exhorting students to write in the active voice.
A Tale of Two Islands
Fable about a controversy in queueing theory over operational analysis. First published in 1991. Contained as an appendix to a 2006 overview of operational analysis


* Computation is the principle; the computer is the tool. * All speech is free. It's just the consequences that get you. * A request is not in the words you speak. It is in the listening of those who hear you. * After many years of trying to make computers think like brains, AI researchers got brains that think they are computers. * Locality is a principle of nature. Caching works because our brains organize information by localities. * Innovation is not brilliant new ideas; it is new practice adopted by a community. * Solidarity, not software, generates collaboration.


Denning is the author or editor of 340 technical papers and eleven books. Books, a selection: * 1973, with Ed Coffman. ''Operating Systems Theory''. Prentice-Hall. * 1978, with Jack Dennis and Joe Qualitz. ''Machines, Languages, and Computation''. Prentice-Hall. * 1997, with Bob Metcalfe (eds.) ''Beyond Calculation: The Next 50 Years of Computing''. Copernicus Books. * 2001. ''The Invisible Future: The Seamless Integration of Technology in Everyday Life.'' McGraw-Hill. * 2010. ''The Innovator's Way: Essential Practices for Successful Innovation.'' MIT Press. * 2015. ''Great Principles of Computing.'' MIT Press. * 2019, with Matti Tedre. ''Computational Thinking.'' MIT Press. Articles, a selection: * 1968. "The Working Set Model for Program Behavior". ACM ''Communications'' (May). * 1970. "Virtual memory." ACM ''Computing Surveys'' (September). * 1970. "Thrashing: Its Causes and Prevention". * 1976. "Fault tolerant operating systems". ACM ''Computing Surveys'' (December) * 1978. with Jeff Buzen. "Operational Analysis of Queueing Network Models." ACM ''Computing Surveys'' (September). * 1980. "Working sets past and present". From IEEE ''Transactions Software Engineering'', January 1980. * 1984, with Robert Brown. "Operating Systems". ''Scientific American'' issue on software. * 1990, with Walter Tichy. "Highly parallel computation". ''Science'' magazine, November. * 1992. "Educating a new engineer". ACM ''Communications'' (December). * 2006. "The Locality Principle". Chapter in ''Communication Networks and Systems'' (J Barria, Ed.). Imperial College Press. * 2007. "Computing is a natural science." ACM ''Communications'' (July). * 2009, with Peter Freeman. "Computing's Paradigm". ACM ''Communications'' (December). * 2010, with Fernando Flores and Peter Luzmore. "Orchestrating Coordination in Pluralistic Networks". ACM ''Communications'' (March).

Personal life

He married Dorothy E. Denning in 1974, a noted computer security expert.


External links

Great Principles site

Art of Operating Systems
book site.
CS Unplugged
a working application of principles in education.
ACM Digital Library

Peter J. Denning, Oral history interview
10 April 2013. Charles Babbage Institute, University of Minnesota
Peter J. Denning, Oral history interview
6–8 August 2007 Association for Computing Machinery {{DEFAULTSORT:Denning, Peter J. 1942 births American computer scientists Computer systems researchers Fellows of the Association for Computing Machinery Presidents of the Association for Computing Machinery Living people Manhattan College alumni Multics people Naval Postgraduate School faculty American software engineers Computer science educators Internet pioneers Fairfield College Preparatory School alumni