David Walden, a computer scientist who helped develop a machine that would become the backbone of the Internet for decades, died April 27 at his home in East Sandwich, Massachusetts. He was 79.
The cause was complications from mantle cell lymphoma, said his wife, Sara Walden.
In 1969, Mr. Walden was part of a small team of talented young engineers whose mission was to build the Interface Message Processor. Its function was to exchange data between computers linked to the nascent Arpanet, the forerunner of the Internet. The first IMP was installed that year at the University of California, Los Angeles. The GMPs would be crucial to the internet until the Arpanet was dismantled in 1989.
Mr. Walden was the first computer programmer to work with the team. “The IMP guys,” as they came to call themselves, developed the computer over nine hectic months under a contract signed by Bolt Beranek and Newman (now Raytheon BBN), a Cambridge, Massachusetts-based technology company.
The IMPs served as translators between mainframe computers in different locations and the network itself. Each IMP translated what came over the network into the specific language of that location’s main computer. The translation work of the IMP evolved to today’s network routers.
The work of Mr. Walden and his colleagues was unprecedented. “They had no models to draw on,” said Marc Weber, curatorial director of the Computer History Museum in Mountain View, California. “They created a new class of machines from complete material.”
He added: “They took a whole new idea at the time and turned it into a living, breathing, working machine with its own software and protocols that became an essential part of the network that grew to connect us all.”
David Corydon Walden was born on June 7, 1942 in Longview, Washington, in the southwestern part of the state. His mother, Velva (Diede) Walden, taught elementary school; his father, Clarence, taught chemistry and physics in high school. The family moved to the San Francisco Bay Area when Mr. Walden was four.
An avid bridge player from an early age, Mr. Walden helped support himself as a student at the University of California, Berkeley, by working at a local bridge club. But his passion for the game was so intense that he dropped out of college after a semester due to poor grades, his wife said.
Mr. Walden eventually enrolled at San Francisco State College (now university) and received his bachelor’s degree in Mathematics in 1964. His interest in computer science grew through a numerical analysis course he took on an IBM computer.
After college, he went to work for the Lincoln Laboratory at the Massachusetts Institute of Technology as a computer programmer in the Space Communications Division.
In 1965 he met Sara Elizabeth Cowles, an education clerk, and they married the following year. He was hired by Bolt Beranek and Newman in 1967. Shortly after, the company won a contract to build the first IMP.
“It was a very small group that worked together all the time,” said Mr. Walden said in a 1990 interview with the Charles Babbage Institute at the University of Minnesota, an archival and research center specializing in information technology.
“We were in and out of each other’s offices, helping each other debug,” he added.
Each discovery sparked excitement. “We’d run in and say, ‘Look, I’ve got this running!'” he said.
Mr. Walden left Bolt Beranek in 1970 for a year to join Norsk Data and helped that company build a computer modeled on the IMP. He returned to Bolt Beranek in 1971 and stayed there until 1995. He later became an expert in management. He was an avid computer historian and 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 hold a senior degree, Mr. Walden received an honorary doctorate from California State University in 2014 for his work at Arpanet. “He has told me more than once that he never thought he would receive such an honor,” Alex McKenzie, a former colleague of Mr Walden’s, said in an interview.
Besides his wife, Mr. Walden leaves behind his son Luke; his brother, Daniel; his sister, Velma Walden Hampson; and two grandchildren.