# Ole-Johan Dahl

> Norwegian computer scientist (1931–2002)

**Wikidata**: [Q92745](https://www.wikidata.org/wiki/Q92745)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Ole-Johan_Dahl)  
**Source**: https://4ort.xyz/entity/ole-johan-dahl

## Summary
Ole-Johan Dahl was a Norwegian computer scientist who lived from 1931 to 2002. He is best known as a co-creator of the Simula programming language, which introduced foundational object-oriented programming concepts that influenced most modern programming languages.

## Biography
- Born: October 12, 1931 in Mandal, Norway
- Nationality: Norwegian
- Education: University of Oslo
- Known for: Co-creation of Simula programming language (1962)
- Employer(s): University of Oslo
- Field(s): Computer science

## Contributions
Ole-Johan Dahl, alongside his collaborator Kristen Nygaard, developed Simula in 1962, which was the first programming language to introduce object-oriented programming concepts. Simula was designed specifically for system simulation but fundamentally changed programming paradigms by introducing classes, objects, inheritance, and dynamic dispatch. These concepts became foundational to later programming languages such as Smalltalk, Java, C++, and C#. The development of Simula established Dahl and Nygaard as pioneers in computer science and earned them the 2001 Turing Award, often referred to as the "Nobel Prize of Computing," for their "ideas fundamental to the emergence of object-oriented programming."

## FAQs
### Q: What is Ole-Johan Dahl most famous for?
A: Ole-Johan Dahl is most famous for co-creating the Simula programming language in 1962, which was the first to introduce object-oriented programming concepts that later influenced most modern programming languages.

### Q: What awards did Ole-Johan Dahl receive?
A: Dahl received numerous prestigious awards including the 2001 Turing Award, the IEEE John von Neumann Medal in 2002, the Commander of the Order of St. Olav, and the Rosing Honorary Award in 1999. He was also awarded an honorary doctorate from ETH Zürich in 2000.

### Q: Who was Ole-Johan Dahl's collaborator on Simula?
A: Ole-Johan Dahl collaborated with Kristen Nygaard on the development of Simula. Their partnership continued throughout their careers, and they shared many of their major awards including the Turing Award.

### Q: What educational background did Ole-Johan Dahl have?
A: Ole-Johan Dahl was educated at the University of Oslo. He later became a university teacher there as well, establishing a long association with the institution.

### Q: What was Ole-Johan Dahl's Erdős number?
A: Ole-Johan Dahl had an Erdős number of 5, indicating a collaborative chain linking him to the mathematician Paul Erdős through co-authors in mathematical research.

## Why They Matter
Ole-Johan Dahl's work fundamentally reshaped computer science through the development of object-oriented programming concepts with Simula. Before Simula, programming was primarily procedural; after it, the focus shifted toward modeling systems as collections of interacting objects. This paradigm shift enabled more intuitive coding for complex systems and directly influenced most modern programming languages used today. Without Dahl and Nygaard's innovations, software development would likely be significantly more difficult, with less reusable code and fewer tools for managing system complexity. Their work laid the foundation for the software development methodologies that now dominate the industry.

## Notable For
- Co-creator of Simula, the first object-oriented programming language (1962)
- Recipient of the Turing Award (2001) for fundamental contributions to object-oriented programming
- Received the IEEE John von Neumann Medal (2002) for pioneering work in programming languages
- Developed early programming concepts that influenced modern languages like Java, C++, and Python
- Member of the Norwegian Academy of Science and Letters and Academia Europaea

## Body
### Personal Information
- Full name: Ole-Johan Dahl
- Birth date: October 12, 1931
- Birth place: Mandal, Norway
- Death date: June 29, 2002
- Death place: Asker, Norway
- Nationality: Norwegian
- Gender: Male
- Languages spoken: Norwegian, English

### Professional Life
- Occupation: Computer scientist, engineer, university teacher
- Field of work: Computer science
- Employer: University of Oslo
- Education: University of Oslo

### Major Achievements
- Co-developed Simula programming language in 1962, introducing object-oriented concepts
- Shared the 2001 Turing Award with Kristen Nygaard for "ideas fundamental to the emergence of object-oriented programming"
- Received the IEEE John von Neumann Medal in 2002 (with Kristen Nygaard)
- Awarded Commander of the Order of St. Olav
- Received the Rosing Honorary Award in 1999 (with Kristen Nygaard)
- Awarded honorary doctorate from ETH Zürich in 2000

### Academic Affiliations
- Member of the Norwegian Academy of Science and Letters
- Member of Academia Europaea
- Associated with the University of Oslo as both educator and researcher

### Identification in Library Systems
- ISNI: 0000000114970591
- GND ID: 128965967
- VIAF ID: 110397937
- Library of Congress Authority ID: n50041578
- DBLP Author ID: d/OleJohanDahl
- Scopus Author ID: 16512366700
- zbMath Author ID: dahl.ole-johan

## References

1. [Great Norwegian Encyclopedia](https://snl.no/Ole-Johan_Dahl)
2. Aftenposten
3. Virtual International Authority File
4. [LIBRIS. 2012](https://libris.kb.se/katalogisering/xv8bb7wg26gltf7)
5. [Source](https://amturing.acm.org/award_winners/dahl_6917600.cfm)
6. [Source](https://www.ieee.org/about/awards/bios/vonneumann-recipients.html#2019%20-%20Eva%20Tardos)
7. [Source](https://inf.ethz.ch/de/departement/auszeichnungen-und-rankings/ehrendoktoren.html)
8. International Standard Name Identifier
9. CiNii Research
10. Freebase Data Dumps. 2013
11. National Library of Israel Names and Subjects Authority File