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star Main Achievements

Profile of Ole-Johan Dahl
star first professor in computer science in Norway (1968)
star Known for the Simula programming language (with Nygaard)
star Known for inventing object-oriented (OO) programming (with Nygaard)
star Won The ACM Turing Award (with Nygaard)
star Won the IEEE John von Neumann Medal (with Nygaard)
star Was made Commander of The Order of Saint Olav (with Nygaard)
star Founder of the discipline of computer science at the University of Oslo
star research in formal methods

Ole-Johan Dahl (October 12, 1931 / June 29, 2002) was a Norwegian computer scientist and is considered to be the father of Simula and object-oriented programming, together with Kristen Nygaard.

Dahl is a member of the small group of scientists who will be regarded as founders of their own field of science. His field was informatics and he won the two most prestigious international prizes specific to that field: The ACM A.M. Turing Award (considered to be the "Nobel Prize of Computing"), in 2001 and the IEEE John von Neumann Medal. He was made Commander of The Order of Saint Olav by the King of Norway in 2000, and received a number of other signs of recognition.

With Kristen Nygaard, he produced the initial ideas for object-oriented (OO) programming in the 1960s at the Norwegian Computing Center (NR - Norsk Regnesentral) as part of the Simula I (1961-1965) and Simula 67 (1965-1968) simulation programming languages

Dahl and Nygaard were the first to develop the concepts of class, subclass (allowing information hiding), inheritance, dynamic object creation, etc., all important aspects of the OO paradigm. Their work has led to a fundamental change in how software systems are designed and programmed, resulting in reusable, reliable, scalable applications that have streamlined the process of writing software code and facilitated software programming. Current object-oriented programming languages include C++ and Java, both widely used in programming a wide range of applications from large-scale distributed systems to small, personal applications, including personal computers, home entertainment devices, and stand-alone arcade applications.

Dahl became a full professor in 1968 at the University of Oslo, creating the discipline of computer science here. He was the first professor of informatics, responsible for establishing research and education programs in this rapidly expanding field. Here he worked on Hierarchical Program Structures, probably his most influential publication, which appeared co-authored with C.A.R. Hoare in the influential book Structured Programming of 1972 by Dahl, Dijkstra and Hoare, perhaps the best-known academic book concerning software in the 1970s.

In his University career, Dahl focused on the use of formal methods, to rigorously reason about programs. Unlike many theoretical computer scientists at the time, his work had a solid motivation in practical applicability and implementation experience. With Owe, who became his closest collaborator, he investigated languages, specification, verification and related tool development, in the long term ABEL project, and in the development of formal methods for object-orientation. His research is today represented and continued by the PMA research group.

pin external resources
[From Object-Orientation to Formal Methods: Essays in Memory of Ole-Johan Dahl, Olaf Owe, Stein Krogdahl and Tom Lyche (eds.), Springer, Lecture Notes in Computer Science, Volume 2635, 2004.]
[Ole-Johan Dahl. (2007, March 6). In Wikipedia, The Free Encyclopedia. Retrieved 17:27, March 19, 2007, from ]
[Virtual Exhibition. In People Behind Informatics. Retrieved 20:03, March 19, 2007, from ]
[Bertrand Meyer, In memory of Ole-Johan Dahl and Kristen Nygaard. In Journal of Object Technology, vol. 1, no. 4, September-October 2002.]
[Ole-Johan's own homepage.]
[The department's page of tribute .]
[ACM press release about the Turing award .]
[Information about the von Neumann Medal.]
[A Norwegian newspaper's article.]
Editors: Olaf Owe, Ioana Prisacariu, The administration at Department of Informatics
Document created: 07.05.2007

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