Ole-Johan Dahl

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Ole-Johan Dahl (born October 12, 1931 in Mandal , Norway ; † June 29, 2002 in Asker , Norway) was a Norwegian computer scientist and Turing Prize winner .


Dahl was born in 1931 as the eldest son of a seafaring family. He studied numerical mathematics at the University of Oslo from 1949 and did his military service during his studies from 1952 at the Forsvarets forskningsinstitutt (FFI, Research Institute of the Norwegian Armed Forces), where he worked on the programming of military computers under Jan V. Garwick and his assistant Kristen Nygaard . Among other things, he designed the higher-level programming language MAC (Mercury Automatic Coding) for the Ferranti Mercury . In 1957 he presented his thesis on the Candidatus realium on the representation and manipulation of multidimensional fields ( arrays ), Multiple Index Countings on the Ferranti Mercury Computer . He then took a full-time position at FFI, becoming Garwick's closest collaborator, while Nygaard devoted himself more to operations research and eventually moved to Norsk Regnesentral (NR, Norwegian Computing Center), of which he became director of research. Dahl supported him as an expert in programming language design in the project to develop the programming languages Simula I (1961-1965) and Simula 67, which is considered the first object-oriented computer language, and followed him in 1963 to the NR.

In 1968 he was appointed the first professor of computer science in Norway at the University of Oslo. For years he practically built up the course on his own, but stopped working on the further development of Simula in order to devote himself more to the theoretical basics of computer science and in particular the programming languages ​​and the correctness of programs. He stayed in Oslo until his retirement in 1999.

In 2001 he and Nygaard received the John von Neumann Medal from the IEEE and the Turing Award from the ACM . The Norwegian king appointed him and Kristen Nygaard as commanders of the Saint Olav Order in 2000 . He was also a member of the Norwegian Academy of Sciences , Academia Europaea and honorary member of the Object Management Group and received an honorary doctorate from Lund University .

His marriage to his wife Tove (1963) resulted in two children.

Ole-Johan Dahl died of cancer on June 29, 2002, his friend and colleague Kristen Nygaard died in August. The Association Internationale pour les Technologies Objets has been awarding the Dahl Nygaard Prize annually since 2005 in their memory.



  • Olaf Owe, Stein Krogdahl, Tom Lyche (Eds.): From Object-Orientation to Formal Methods. Essays in Memory of Ole-Johan Dahl , Springer, Lecture Notes in Computer Science, Volume 2635, 2004, ISBN 3-540-21366-X , doi : 10.1007 / b96089

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