October 12, 1998

David Evans, 74, Pioneer in Computer Graphics

By JOHN MARKOFF

avid C. Evans, a pioneer in the field of computer graphics and a noted computer scientist who oversaw the education of some of the computer industry's most influential figures, died on Oct. 3 after a long battle with Alzheimer's disease, his family said. He was 74 years old.

Evans, who was a native of Salt Lake City, was also the co-founder with Ivan Sutherland of Evans & Sutherland Computer Corp., a maker of powerful graphics systems that are used for engineering, scientific and military applications that require a detailed visual rendering on a computer screen.

During stints in the 1960s as chairman of the computer science departments at the University of California at Berkeley and at the University of Utah, Evans was closely associated with an era of pioneering work that paved the way for the modern computer industry.

"There was a flowering of technology at the University of Utah and his students took these ideas and ran with them," said Sutherland, who is now a vice president and computer researcher at Sun Microsystems Inc. "His strength was that he realized the department couldn't do everything and so he decided to do one thing well and that was graphics."

Still, his best students went on to develop seminal ideas that were instrumental in creating some of the most influential companies in various branches of the computer industry.

Evans studied electrical engineering at the University of Utah and earned a doctorate in physics. He then went to work at Bendix Corp., where he served as a project manager on two of the company's computers, the G15, introduced in 1955, and the G20, introduced in 1961.

But Evans, correctly predicting that Bendix was not going to succeed in the computer industry, left to join the computer science department at the University of California at Berkeley. He became the head of the university's work for the Pentagon's Advanced Research Project Agency, known as ARPA.

At that time, the agency was funding a broad range of basic research projects from which grew many of the key innovations of the modern computer industry in personal computing, networking and work stations.

At Berkeley, Evans and his students made advances in the area of virtual memory, an important concept in computer science that allows the size of programs and data files to exceed the actual memory size of a computer.

He also led a group of students and researchers in the design of a computer that became known as the SDS 940. Brought to market in the mid-1960s by Xerox Corp., it was the first commercial time-sharing computer system, enabling a number of computer users to simultaneously use a single computer.

One of Evans' best-known Berkeley students was Butler Lampson, who became a pioneer in the development of personal computers and work stations at Xerox's Palo Alto Research Center and at Digital Equipment Corp.

While at Berkeley, Evans also met Sutherland, who had recently become head of ARPA's Information Processing Techniques Office.

In 1965, James Fletcher, then president of the University of Utah, recruited Evans to move back to Salt Lake City and create a computer science department.

Three years later, Evans recruited Sutherland to a faculty position at Utah from Harvard, where after leaving ARPA he had been conducting research in head-mounted display screens for airplane pilots and other applications.

It was in 1968, during a dinner conversation while the two men were on a business consulting trip in Phoenix, that they decided to start Evans & Sutherland Computer even while continuing the work at the university.

Sutherland said that Evans' distinctive contribution in computer graphics was in the insight that each individual point in a computer image -- each pixel -- differs only incrementally from the pixels adjacent to it. By computing only these differences, rather than creating an entirely new pixel in each instance, a computer can reserve tremendous amounts of processing power and speed for the creation of more complex graphics than would otherwise be possible.

He also led a group working on "raster" computer graphics -- building images by computing and displaying them an entire horizontal screen line at a time -- a popular alternative to the "vector" method, in which an electronic beam scans an image onto a screen much as a pencil draws a picture on paper.

However, Evans' greatest contribution may have been the fact that at both Berkeley and Utah, he recruited and taught an extraordinary group of graduate students who went on to groundbreaking careers in computing.

Among the best known of his former Utah students are Alan Kay, who later became the leader of a group of researchers at Xerox's Palo Alto Research Center credited with many of the ideas underlying the modern personal-computer industry; Jim Clark, a founder of Silicon Graphics Inc., a maker of advanced work stations, and Netscape Communications Corp., the company that first successfully commercialized the World Wide Web browser; John Warnock, a co-founder of Adobe Systems Inc., whose printing software helped create the desktop publishing industry; Edwin Catmull, a computer graphics pioneer who co-founded Pixar, the computer animation studio, and Alan Ashton, co-founder of Wordperfect Corp.

"If you look at the industry today and see where the ideas come, many of the best ones came from Dave," said Kay, who is now a research scientist at Walt Disney Corp.

"All of us were misfits and late bloomers," Kay said of Evans' former students. "But if your resume looked at all interesting, he would let you in and give you two years of support."

Among Evans' professional honors was the 1996 Computer World-Smithsonian Award for lifetime achievement.

He was an active member of the Church of Latter Day Saints and a Boy Scout scoutmaster for 27 years, receiving the Silver Beaver, scouting's highest honor for adult leaders.

Evans is survived by his wife, Beverly Joy Frewin Evans, and by seven children: Anne Brown of Palo Alto, Calif.; Peter Evans, Gayle Gable and Katherine Orchard all of Salt Lake City; David Evans of Japan; Douglas Evans of Fort Collins, Texas, and Susan Foote of Flower Mound, Texas, as well as 39 grandchildren and great-grandchildren.