Gordon Bell, the Master Architect of Personal Computers, Dies at 89

While Gordon Bell’s law is not as well known as Gordon Moore’s law, it is perhaps just as important as a structural corollary. 

 

Chester Gordon Bell: August 19, 1934 to May 17, 2024. Image used courtesy of Queensland University of Technology via Wikimedia Commons

 

Bell’s law of computer classes gave us the architectural class definitions of mainframe, minicomputer, and microcomputer—and a framework to go beyond.

 

Early Life and Education

Bell was born August 19, 1934, in Kirkville, Missouri, to a teacher and an electrician. Bell spent much of his early childhood at home due to illness. That, however, didn’t stop his thirst for knowledge and experimentation. He used his time at home to conduct experiments in chemistry, electricity, and woodworking. As he regained his health, he spent time in his father’s shop learning electrical repair. By the age of 12, he was operating as a professional electrician.

Bell studied electrical engineering at MIT, receiving his BS in 1956 and MS in 1957. A Fullbright Scholarship then took him to the New South Wales University of Technology (now UNSW) in Australia. While at UNSW, Bell taught computer design classes and programmed on the UTECOM/ English Electric DEUCE, one of the first computers in the country. Back at MIT, he started work on a Ph.D. but left before completing it because he lacked interest in the title. Instead, he was eager to enter the industry and create.

 

Bell Introduces the First Minicomputers and UART

In 1960, the computer industry was not far from the era when every new machine was a unique experiment. The mainframe was less than a decade old. Bell joined the Digital Equipment Corp (DEC) that year and got to work on smaller-than-mainframe systems.

At DEC, he designed the PDP-1 I/O system and was a key designer and architect for much of the PDP line of minicomputers. It was during this time that Bell formed his ideas on classifying computers based on decreasing the cost and size of components while increasing performance. 

 

PDP-1 user manual cover image. Image used courtesy of the Computer History Museum

 

As a part of his design of the PDP-1 I/O system, he invented the world’s first digital universal asynchronous receiver transmitter (UART). The single-chip UART progeny of Bell’s design was one of the first common very large-scale integration (VLSI) chips and one of the key communications chips that enabled computers to communicate inexpensively with each other and peripheral devices.

 

The Birth of Bell's Law of Computer Classes

Bell first publicly stated his law in 1970, when the DEC PDP-11 minicomputer was released.

 

“Roughly every decade a new, lower-priced computer class forms based on a new programming platform, network, and interface resulting in new usage and the establishment of a new industry.” – Gordon Bell

 

Though Bell was teaching at Carnegie Mellon University at the time of this conjecture, he drew inspiration for this law at DEC from 1960 to 1966. DEC first recruited Bell in 1960 to help develop the architecture for the programmed data processor (PDP) line of minicomputers, DEC’s entry-level alternative to expensive and bulky mainframes from rivals Univac and IBM. 

Bell left DEC in 1966 for a professorship at Carnegie Mellon. His friend and colleague, Allen Newell suggested Carnegie Mellon as a place welcome to new ideas. Bell didn’t have a Ph.D. nor many published papers at the time, but he did have a vision for the future of computing. He and Newell collaborated to write "Computer Structures: Readings and Examples" (available as a downloadable PDF).

 

PDP-8 instruction decoding diagram as outlined in "Computer Structures: Readings and Examples", page 122. Image courtesy of ResearchGate

 

The work outlined everything from fundamental computer layer structure and logic to a taxonomy for computer architecture that created the way the industry would classify computers, later to be codified into “Bell’s law of computer classes” Bell returned to DEC in 1972 as vice president of engineering. During his second tenure, he formally published his law and created the hugely successful VAX line of minicomputers. He left DEC again in 1983 and co-founded Encore Computer, a company that developed multiple microprocessor-based minicomputers. 

 

Recall, né MyLifeBits

In 1991, Bell was called on by Microsoft to become an advisor for its new research group. He acted in that capacity until joining full-time in 1995. It was then that Bell showed his prescient thinking in Microsoft's experimental program, MyLifeBits.

Today, much of what we do and say can be recorded and saved as a digital chronicle of our lives. But in the 1990s, such thoughts were still largely in the realm of science fiction. Gordon Bell, along with coworker Jim Gemmell, created MyLifeBits as a complete digital recording of one’s life.

The program started as a project to digitize Bell’s published books and morphed into an effort to create a digital repository of his life. In Bell’s vision, an individual's every digital imprint could be captured, saved, and indexed for later access. Today, the legacy of MyLifeBits can be found in Microsoft’s controversial Recall feature of its latest Windows 11 Copilot AI.

 

Bell’s Legacy

Gordon’s work extended far beyond his technical accomplishments. He was an original thinker—a digital philosopher if you will. His contributions are as much about the societal implications of technology as they are about systems design and architecture. Over the years, he was a member of the National Academy of Engineering, a fellow of the American Academy of Arts and Sciences, and a participant in numerous other professional and advisory groups.

Gordon Bell was an avid collector of historical computer hardware. This passion led him to co-found the Digital Computer Museum, now known as the Computer History Museum, with Gwen Bell and DEC co-founder Ken Olsen. The museum is now located in Mountain View, California, and is a must-see stop for tech enthusiasts passing through the South San Francisco Bay area.