Jack Bonnell Dennis (born October 13, 1931) is an American

computer scientist A computer scientist is a scientist who specializes in the academic study of computer science. Computer scientists typically work on the theoretical side of computation. Although computer scientists can also focus their work and research on ...

and Emeritus Professor of Computer Science and Engineering at

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...

. The work of Dennis in

computer systems A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

and

computer languages A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Construction language – all forms of communication by which a human can specify an executable problem solution to a comput ...

is recognized to have played a key role in

hacker A hacker is a person skilled in information technology who achieves goals and solves problems by non-standard means. The term has become associated in popular culture with a security hackersomeone with knowledge of bug (computing), bugs or exp ...

culture. As a

faculty member he sponsored easier access to computer facilities at MIT during the early development of the subculture. Much of what would later become

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

came from his early collaboration with

Dennis Ritchie Dennis MacAlistair Ritchie (September 9, 1941 – October 12, 2011) was an American computer scientist. He created the C programming language and the Unix operating system and B language with long-time colleague Ken Thompson. Ritchie and Thomp ...

and

Ken Thompson Kenneth Lane Thompson (born February 4, 1943) is an American pioneer of computer science. Thompson worked at Bell Labs for most of his career where he designed and implemented the original Unix operating system. He also invented the B (programmi ...

. This collaborative and open philosophy lives on today. Dennis was also a member of the

Tech Model Railroad Club The Tech Model Railroad Club (TMRC) is a student organization at the Massachusetts Institute of Technology (MIT). Historically, it has been a wellspring of hacker culture and the oldest such hacking group in North America. Formed in 1946, its HO ...

, which incubated much of the early slang and traditions of hacking.

Early life and education

Dennis graduated from the

(MIT) as Bachelor of Science (1953), Master of Science (1954), and Doctor of Science (1958). His doctoral thesis analyzed the relation between mathematical programming problems and electrical networks. After completing his doctorate, Dennis became part of the MIT's Department of Electrical Engineering and Computer Science's faculty, being promoted to full professor in 1969.

Career

As a professor at MIT, Dennis was influential in the work of student

Alan Kotok Alan Kotok (November 9, 1941 – May 26, 2006) was an American computer scientist known for his work at Digital Equipment Corporation (Digital, or DEC) and at the World Wide Web Consortium (W3C). Steven Levy, in his book '' Hackers: Heroes of th ...

and fellow professors

Marvin Minsky Marvin Lee Minsky (August 9, 1927 – January 24, 2016) was an American cognitive scientist, cognitive and computer scientist concerned largely with research in artificial intelligence (AI). He co-founded the Massachusetts Institute of Technology ...

and

John McCarthy John McCarthy may refer to: Government * John George MacCarthy (1829–1892), Member of Parliament for Mallow constituency, 1874–1880 * John McCarthy (Irish politician) (1862–1893), Member of Parliament for the Mid Tipperary constituency, ...

. He gave young programmers access to multi-million dollar computers and allowed them to see where their abilities could take them, inspiring a generation of MIT graduates who would shape the computer industry at DEC,

Xerox Xerox Holdings Corporation (, ) is an American corporation that sells print and electronic document, digital document products and services in more than 160 countries. Xerox was the pioneer of the photocopier market, beginning with the introduc ...

Parc and ARPA. Dennis was one of the founders of the

Multics Multics ("MULTiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of t ...

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 system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

s, most importantly the direct inspiration for

(who also worked on the project) to design the first incarnation of

. 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 has also worked as an independent consultant and research scientist on projects related with parallel computer hardware and software since his retirement from MIT in 1987. He has 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 has been devoted to non-

von Neumann model The von Neumann architecture—also known as the von Neumann model or Princeton architecture—is a computer architecture based on the ''First Draft of a Report on the EDVAC'', written by John von Neumann in 1945, describing designs discuss ...

s 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 In computer programming, an assignment statement sets and/or re-sets the value stored in the storage location(s) denoted by a variable name; in other words, it copies a value into the variable. In most imperative programming languages, the ass ...

and

dataflow In computing, dataflow is a broad concept, which has various meanings depending on the application and context. In the context of software architecture, data flow relates to stream processing or reactive programming. Software architecture Dat ...

, 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 The National Academy of Engineering (NAE) is an American Nonprofit organization, nonprofit, NGO, non-governmental organization. It is part of the National Academies of Sciences, Engineering, and Medicine (NASEM), along with the National Academ ...

for contributions to sharing and protection in computer systems and parallel architectures based on data flow principles.

Awards and recognitions

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...

John von Neumann Medal, 2013 *

Association for Computing Machinery The Association for Computing Machinery (ACM) is a US-based international learned society for computing. It was founded in 1947 and is the world's largest scientific and educational computing society. The ACM is a non-profit professional membe ...

(ACM) Special Interest Group on Operating Systems (SIGOPS) Hall of Fame, 2012 * Member of the

(NAE), 2009 * Eckert-Mauchly Award, 1984 *

Fellow *

ACM Fellow ACM Fellowship is an award and fellowship that recognises outstanding members of the Association for Computing Machinery (ACM). The title of ACM Fellow A fellow is a title and form of address for distinguished, learned, or skilled individuals ...

References

External links

Jack B. Dennis home page
*

Photograph of Jack B. Dennis

Oral history interview with Jack B. Dennis
at the

Charles Babbage Institute The IT History Society (ITHS) is an organization that supports the history and scholarship of information technology by encouraging, fostering, and facilitating archival and historical research. Formerly known as the Charles Babbage Foundation, ...

, University of Minnesota. Dennis describes his educational background and work in time-sharing computer systems at the Massachusetts Institute of Technology (MIT), including the

TX-0 The TX-0, for ''Transistorized Experimental computer zero'', but affectionately referred to as tixo (pronounced "tix oh"), was an early fully transistorized computer and contained a then-huge 64Kilo-, K of 18-bit words of magnetic-core memory. C ...

computer, the work of

on time-sharing, and the influence of the

Information Processing Techniques Office The Information Processing Techniques Office (IPTO), originally "Command and Control Research",Lyon, Matthew; Hafner, Katie (1999-08-19). ''Where Wizards Stay Up Late: The Origins Of The Internet'' (p. 39). Simon & Schuster. Kindle Edition. was par ...

of the Advanced Research Projects Agency. Dennis also recalls the competition between

Digital Equipment Corporation Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president until ...

General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...

, Burroughs, and

International Business Machines International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

, to manufacture time-sharing systems. He describes the development of

MULTICS Multics ("MULTiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of t ...

at General Electric.
Toward the Computer Utility: A Career in Computer System Architecture — Jack B. Dennis

{{DEFAULTSORT:Dennis, Jack B. 1931 births Living people American computer scientists American electrical engineers MIT School of Engineering alumni MIT School of Engineering faculty Members of the United States National Academy of Engineering Multics people 1994 fellows of the Association for Computing Machinery