“The Alto was the thing that galvanized the hardware and software technology of the next 45 years, and astoundingly it was done by Chuck in just three months,” said Mr. Kay. “We used to say that Chuck threw the parts up in the air and they fell down Alto.”
With his work on the Alto, Mr. Thacker was also well ahead of his time in tablet computing. In 1968, Mr. Kay had the idea to build a portable computing machine he called the Dynabook, which he envisioned as far more than a stand-alone device. Rather, it would enable a user to stay in a networked environment, the likes of which were just being developed at the time.
Knowing such a device would be many years in the making, Mr. Kay described to Mr. Thacker a prototype, much larger than a tablet, that would eventually run the software of the Dynabook.
“Chuck loved this idea, and this became part of his goals for the Alto,” Mr. Kay said. “Its original name was Interim Dynabook.”
Mr. Thacker left Xerox PARC in 1983 to help start Digital Equipment Corporation’s Systems Research Center in Palo Alto, where he led the design of an experimental computer called Firefly.
But he did not give up on the idea of a tablet computer. (“In systems research, one of the most motivating things is that you want the device yourself,” he said of his persistence.)
In 1997, he went to work for Microsoft and within two years had joined the company’s Tablet PC group and was managing the design of the first prototypes of the new device.
Yet commercial success for the tablet remained vexingly elusive until a number of technologies — processing, display, battery and storage — could converge. When the Apple iPad was introduced in 2010, the commercial prospects for tablet computing brightened considerably.
Although Mr. Thacker was principally a hardware engineer, he was also a deft programmer. “He was a hardware genius who was also great at software,” Mr. Kay said.
Mr. Thacker’s foresight did not stop with computers. While at PARC, he helped invent Ethernet, a combination of hardware and software for linking computers. Like personal computers, Ethernet-based local-area networks have become ubiquitous.
Charles Patrick Thacker was born in Pasadena, Calif., on Feb. 26, 1943. His mother, Fern, was a cashier and secretary at Boys, a grocery store in Los Angeles. His father, Ralph, an electrical engineer, left the family when Mr. Thacker was young. His mother raised her two sons on her own.
When he was 16, Mr. Thacker received a scholarship to study physics at the California Institute of Technology. He soon transferred to the University of California, Los Angeles. In 1963, he met Karen Baker, an undergraduate at the University of California, Berkeley, who had returned home to Pasadena for the summer. In love, Mr. Thacker bucked the norms of the era and followed Karen north, transferring this time to UC Berkeley. They married in 1964. She survives him.
Besides her and their daughter Christine, he is survived by another daughter, Kathy Bellairs, and two grandchildren.
Mr. Thacker worked his way through UC Berkeley as a machinist for a man named Jack Hawley, whom Mr. Thacker described as “the sole proprietor of an inventorship” in Albany, Calif.
“I made him a deal he couldn’t refuse,” Mr. Thacker told an interviewer for the Computer History Museum in 2007. “I said, ‘I’ll design your electronics for you, if you teach me how to run all your machine tools.’”
Mr. Thacker received his bachelor’s degree in physics in 1967. “I wanted to be a physicist, not because of the physics but because of the engineering part of it,” he said.
Indeed, he had already gravitated to computing while an undergraduate, and in 1968 he went to work for the university’s Project Genie, an effort that resulted in an early computer time-sharing system. The Genie team later formed the Berkeley Computer Corporation, where Mr. Thacker led the design of a processor for a new computer.
While the corporation was not a commercial success, it supplied the core group of technologists for the newly formed Xerox PARC. Mr. Thacker, along with a small group of others, went to work there in 1970.
Before his retirement from Microsoft, in February, Mr. Thacker was running a research laboratory, moving back and forth between the research and the product development sides of the company. He even did a stint working on Microsoft’s Xbox 360 game console when a top engineer on the project became ill.
Christine Thacker said her father had been especially animated when he talked about work.
“When I was 8 years old, he would read to me from ‘The Feynman Lectures on Physics,’” she said, referring to Richard P. Feynman, the Nobel Prize-winning theoretical physicist, “and explain to me how bitmap displays render fonts. He’d talk about his work even if we had no idea what it was. Everything he worked on was this great big adventure for him.”