The New York Times

August 14, 2002

Kristen Nygaard, Who Built Framework for Computer Languages, Dies at 75


Kristen Nygaard, a Norwegian mathematician who laid the groundwork for modern computer programming languages and who helped Scandinavian workers influence the design of labor-saving computer technologies, died on Saturday in Oslo, Norway. He was 75.

The cause of death was a heart attack, said Ole Lehrmann Madsen, a friend and colleague at Aarhus University in Denmark.

From 1962 to 1967, with his co-worker Ole-Johan Dahl, Mr. Nygaard designed Simula, a programming language intended to simulate complex real-world systems. The ideas underlying Simula emerged from Mr. Nygaard's work in the area of operations research while he was employed at the Norwegian Defense Research Establishment from 1948 to 1960.

Although the original use for Simula was a physics simulation for a military laboratory, workers at the Norwegian Iron and Metal Union approached Mr. Nygaard, in the late 1960's with concerns about computers in displacing and altering their jobs. Mr. Nygaard began working with them, pioneering an approach that became known as participatory design, in which workers help design new technologies in the workplace.

"It was originally thought of as a socialistic movement," said Dr. Madsen, who worked with Mr. Nygaard over several decades. "However, eventually large corporations began to realize this was a reasonable practice and it is widely used around the globe today."

Simula was significant for pioneering the concept of "object oriented" programming. Before Simula, computer programs were thought of in terms of software instructions and data. Simula introduced the idea of objects, or modules, and classes of objects. Such object-based programs made it easy for programmers to reuse software, thus dramatically increasing productivity and efficiency.

"He understood that simulation was the ultimate application of computers," said Larry Tesler, a computer scientist who has worked at the Xerox Corporation and Apple Computer. "It was a brilliant stroke."

Simula would ultimately influence the designers of a wide range of programming languages, including Smalltalk, C++, and Java, and it would leave a deep impression on the personal computer world as well, influencing the designers of both the Macintosh and Windows operating systems.

As a graduate student at the University of Utah, the computer scientist Alan Kay became familiar with Simula, which was to become one of the principal influences on Smalltalk, an object-oriented programming language he developed with a small group of programmers at Xerox's Palo Alto Research Center in the early 1970's. Because Simula permitted the creation of classes of objects and permitted "inheritance," in which all the objects of a class could automatically take on certain attributes, it led Dr. Kay to begin thinking in biological terms. He conceived of software in a framework where complex processes could emerge from simple building blocks.

The Palo Alto research in turn influenced a generation of computer designers at both Apple Computer and the Microsoft Corporation in the early 1980's, when the modern personal computer was taking form.

Several years after Dr. Kay discovered Simula, Bjarne Stroustrup, a Danish programmer who studied at Cambridge and who would later become a software designer at Bell Laboratories, also encountered the language. Like Dr. Kay, he would be influenced by the idea of software objects, and he would build that concept into his widely influential C++ programming language.

Kristen Nygaard was born on Aug. 27, 1926, in Oslo. He received his master's degree in mathematics at the University of Oslo in 1956.

He taught in both Denmark and at the University of Oslo, where he was a professor until he retired in 1996.

In the 1970's, Mr. Nygaard's research interests increasingly turned to the impact of technology on the labor movement, and he became involved in other political, social and environmental issues. He was the first chairman of the environment protection committee of the Norwegian Association for the Protection of Nature. He was also the Norwegian representative for the Organization for Economic Cooperation and Development's activities on information technology.

He also helped run an experimental program to create humane living conditions for alcoholics.

In the mid 1960's he became a member of the National Executive Committee of the Norwegian party Venstre, a left-wing non-socialist party, and chairman of that party's strategy committee. In 1988 he became chairman of a group that successfully opposed Norway's membership in the European Union.

This year, with Ole-Johan Dahl, Mr. Nygaard shared both the Association of Computing Machinery's Turing Award and the Institute for Electrical and Electronics Engineers von Neumann Medal. In 1990 the Computer Professionals for Social Responsibility awarded him the Norbert Wiener Prize.

He is survived by his wife, Johanna Nygaard, three children and seven grandchildren.

Copyright 2002 The New York Times Company