A Small Class at Caltech Helped Launch a Computer Revolution

One of the early advances in computer science began with a small course taught by Carver Mead at Caltech in 1971.

By Robert Perkins

Carver Mead (BS ’56, MS ’57, PhD ’60), the Gordon and Betty Moore Professor of Engineering and Applied Science, Emeritus, received the 2022 Kyoto Prize for Advanced Technology in honor of his “leading contributions to the establishment of the guiding principles for VLSI systems design.” VLSI, which stands for “very large-scale integration,” is the process of combining millions of transistors onto a single chip that forms an integrated circuit. It is the cornerstone of the computers the world relies on today. Mead, a Caltech Distinguished Alumnus, also received the National Medal of Technology in 2002 for his efforts

Mead and computer engineer Lynn Conway wrote the book on the subject, Introduction to VLSI Systems, which was first published in 1978 and became the world standard textbook for chip design. However, the book and the VLSI revolution grew out of an electrical engineering course with an unassuming name, EE 281—Semiconductor Devices, which Mead began teaching to Caltech undergraduate and graduate students in 1971.

The course began with the curiosity of a graduate student, Richard Pashley (MS ’70, PhD ’74). In the early 1970s, Pashley’s PhD adviser, applied physicist James Mayer, had an office on the same floor of Steele Laboratory as Mead’s, so Pashley often ran into him.

“During my second year, I was taking a class in bipolar circuit design, and I wandered into Carver’s lab, and there were a bunch of students working with MOS [metal-oxide semiconductors – building computer chips], Pashley recalls. ” I said, ‘Why aren’t there any classes in this?’ And one of the students said, ‘Go talk to Carver.'”

So Pashley did. Mead told him to find 25 students interested in taking the class—if he could, Mead would teach it.

Interest was high. “It was no sweat to get 25 people to sign up,” Pashley remembers.

In those days, computer chips were designed by hand in a painstaking and expensive process. After carefully drawing out various layers of a circuit on gridded Mylar, engineers had to transfer each individual layer of the pattern onto Rubylith—a Mylar sheet covered with a thin red layer. This layer could be cut into the desired pattern and peeled away from the Mylar to create the inverse pattern that would be photographed, shrunk, and then used as a mask for creating computer chips.

Mead had devised a simple but effective computer program that could encode chip-design patterns for output to a Gerber plotter—at the time the only device by which a computer could generate highly precise complex geometric patterns. Mead’s design process produced more accurate patterns than the industry standard Rubylith, and it required vastly fewer human resources.

The nine remaining students in that first-ever term of EE 281 in 1971 produced eight circuit designs—two students were married and collaborated on one of the designs. Mead grouped the student designs together on a single “multi-project chip,” had the patterns generated at a local Gerber shop, arranged for masks to be made at a mask vendor in Silicon Valley, and delivered the masks to Gerhard Parker at Intel, who arranged for them to be fabricated.

By January 1972, the fabrication was finished, and each student had received a chip and tested it in the lab. “Amazingly, they all worked!” Mead says. The class grew larger each year until Mead stopped teaching it in 1977. “Word got around that this was the future,” Mead says.

Two key things came from the class: firstly, on campus, Mead worked with Ivan Sutherland (MS ’60, formerly Caltech’s Fletcher Jones Professor of Computer Science and recipient of the 2012 Kyoto Prize) to found Caltech’s computer science option in 1976, with the VLSI course at the heart of the new option. “I was able to convince Ivan that integrated circuits would drive computer science, not the other way around,” Mead says.

Carver Mead continued to refine and advance his circuit design process through the course. “Every class I ever taught, I learned as much as the students,” Mead says.

“We are literally 40 years later, and this methodology has become the standard in the industry,” says Fairbairn of the Computer History Museum. “Carver was always way ahead of the game. … The only mistake Carver ever made was being too early.”

Individuals who had taken EE 281 or heard Mead’s various lectures on the topic were spreading throughout the industry. Inspired by what they had learned, they went on to promote and, more importantly, to advance the technology in their own careers.

Mead began teaching at Caltech in 1958. He holds more than 80 U.S. patents and has written more than 100 scientific publications. This year, the Kyoto Prize recipients are Mead, in advanced technology; population biologist Bryan T. Grenfell of Princeton University in basic sciences; and musician Zakir Hussain in arts and philosophy. In 2007, the Kyoto Prize was awarded to Hiroo Kanamori, Caltech’s John E. and Hazel S. Smits Professor of Geophysics, Emeritus, in honor of his “significant contributions to understanding the physical processes of earthquakes and developing seismic hazard mitigation systems to protect human life.” In 2019, Caltech astrophysicist James Gunn (now at Princeton University) received the Kyoto Prize for his leadership in the Sloan Digital Sky Survey, which produced a 3-D digital cosmic map encompassing a broad region.

“The Kyoto Prize is especially precious to me because it recognizes contribution to, not only technology, but, even more, to the human spirit,” Mead says.

> Read the full article on Caltech website.