Mr. Walden eventually enrolled at San Francisco State College (now the University) and received his bachelor’s degree in mathematics in 1964. His interest in computers grew through a course in numerical analysis where he worked on an IBM computer.
After college, he worked for Lincoln Laboratories at the Massachusetts Institute of Technology as a computer programmer in the Space Communications Division.
In 1965 he met Sara Elizabeth Cowles, an education administrator, and they married the next year. He was hired by Bolt Beranek and Newman in 1967. Soon after, the company received an order to build the first IMP
“It was a very small group that worked together all the time,” Mr. Walden called in a 1990 interview with the Charles Babbage Institute at the University of Minnesota, an archives and research center specializing in information technology.
“We used to go in and out of each other’s offices and help each other debug,” he added.
Each discovery sparked excitement. “We ran in and said, ‘Look, I’ve got this going!'” he said.
Mr. Walden left Bolt Beranek for a year in 1970 to work at Norsk Data, helping that company build a computer based on the IMP model. He returned to Bolt Beranek in 1971 and stayed until 1995. He later became an expert in the field of management. An avid computer historian, he was editor of the IEEE Annals of the History of Computing, published by what was originally the Institute of Electrical and Electronics Engineers.
Although he did not have an advanced degree, Mr. Walden received an honorary doctorate from California State University in 2014 for his work on the Arpanet. “He has told me more than once that he never thought he would receive such an honor,” said Alex McKenzie, a former colleague of Mr. Walden, in an interview.
In addition to his wife, Mr. Walden is survived by his son Luke; his brother Daniel; his sister Velma Walden Hampson; and two grandchildren.