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This prolific inventor gave the world advancements from speech recognition to data storage and RISC
Close-up of John Cocke, smiling at the camera in a suit and tie

John Cocke was a highly creative and prolific computer scientist at IBM who made profound contributions to the advancement of information technology. He was responsible for an extraordinary scope of inventions, ranging from software to microprocessors. His work had an impact on gaming, supercomputers and even space travel.

Cocke was born in 1925 in Charlotte, North Carolina, where he was raised. His father was president of the Duke Power Company and a trustee of Duke University. Cocke pursued his undergraduate and graduate studies there, completing a bachelor’s degree in mechanical engineering in 1946 and receiving a doctorate in mathematics in 1956. He then began a 36-year career at IBM.

RISC architecture
A crowning achievement

During his time at the company, Cocke was credited with an array of innovations. He pioneered improvements to the efficiency of software compilers, which translate programming language into the ones and zeros of binary digital code. Additionally, he devised improvements in areas ranging from speech-recognition technology to data storage. But his crowning achievement was in leading a team that realized the promise of reduced instruction set computer architecture, or RISC.

The effort to develop RISC began in 1974, when IBM tasked Cocke and a team of researchers with creating an exchange controller to automate telephone switching — phone calls were then largely handled by human operators who plugged cords into switchboards. Although IBM canceled the controller project in 1975, the team’s efforts morphed into the creation of the first prototype computer that used RISC. The new system’s power and efficiency became foundational to computer evolution up to the present day.

In the 1970s, prior to RISC, computers were built around the complex instruction set computer (CISC) architecture. Under CISC, a machine executed individual instructions for various low-level operations, such as “Load from memory” and arithmetic operations. This process required engineers to insert complicated commands directly into the hardware — a microprocessor would come with a specific instruction set, for example. 

With RISC, Cocke’s team radically reduced the size of the instruction set by identifying and eliminating unused elements. With fewer instructions to execute, the central processing unit (CPU) could perform at a greatly accelerated rate. As a result, RISC could complete an assignment with a single electronic pulse in less than half the time required by a CISC machine. This advancement opened the door to a process known as pipelining, whereby instructions are organized like an assembly line, with many — fetching, decoding, executing — happening simultaneously.

A dizzying intellect, persistent curiosity

Cocke’s friends and colleagues credited him with both a dizzying intellect and persistent curiosity. One of them, Peter Capek, noted: “His career was unusual in its breadth. He was known for his work in computer architecture, but he was interested in everything — circuits, storage, compilers — any technology that could advance the state of the art.”

Throughout his career, Cocke frequently roamed the halls at the Thomas J. Watson Research Center in Yorktown Heights, New York, and beyond. A chain-smoker for much of his life, he reportedly left a trail of cigarette butts and ashes in the many offices he visited. In Cocke’s obituary in The New York Times, Paul Horn, a former IBM Senior VP and Director of IBM Research, recalled that when Cocke worked on the weekends, he was typically in the labs. He would drop by Horn’s office to engage in deep discussions on unification theory in physics. “John Cocke knew as much about high-energy physics as I did,” said Horn, “and it wasn’t even his field.”

Cocke’s memory was also legendary. Frances Allen, an IBM researcher who collaborated with Cocke on compiler inquiries, noted that he possessed an eclectic intellect and itinerant working style that enabled him to keep “dialogues going with people on different subjects that spanned months, even years. He would start up a conversation with you on some detailed technical subject, plunging right in where he left off the last time he saw you a couple of months earlier. It was one of John’s traits that took a little getting used to.”

He also had an air of eccentricity and a singular devotion to his work. (Friends say he often wore the same clothes all week). A longtime bachelor, Cocke finally got married in his sixties to Anne Holloway. According to his obituary, Cocke would also periodically disregard his paychecks and stock certificates. His assistants regularly inspected his trash to retrieve anything of value that he might have discarded inadvertently.

However unconventional Cocke’s methods were, his accomplishments were legion. That is why he received the Association for Computing Machinery’s Turing Award in 1987, the US National Medal of Technology in 1991, and the US National Medal of Science in 1994. Cocke died in 2002, at the age of 77.

He was known for his work in computer architecture, but he was interested in everything — any technology that could advance the state of the art Peter Capek IBM Research staffer
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