Evans died of heart failure at his home in the San Francisco suburb of Hillsborough, his son Robert Evans said.
Evans began working at IBM in 1951 as a junior engineer after earning a bachelor's degree in electrical engineering from Iowa State University. When he retired from IBM 33 years later, he was vice president of engineering, programming and technology.
In the 1960s, Evans led a team that developed a new class of mainframe computers called the System/360, or S/360, which allowed different applications to be run simultaneously. IBM invested $5 billion in the project at a time when the company's annual revenue came to $3.2 billion.
"Prior to the S/360, each computer was a unique system. They were made to an individual customer's order, and there was no continuity from design to design," Colette Martin, the director of zSeries products for IBM, told CNET News.com before thein April. "Prior to the S/360, they were single-application systems."
The architecture introduced in the S/360 is still in use in IBM mainframes.
In 1985, President Ronald Reagan recognized Evans' work on the project with the National Medal of Technology. In 1991, he was presented with a Computer Pioneer Award from the Computing Society of the Institute of Electrical and Electronic Engineers.
From 1981 to 1995, Evans acted as a chief science adviser to the government of Taiwan, and later helped to start Taiwan's Vanguard International Semiconductor Corp.