Gene Amdahl

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Lore & Background

Amdahl was born to immigrant parents of Norwegian and Swedish descent in Flandreau, South Dakota. After serving in the Navy during World War II, he completed a degree in engineering physics at South Dakota State University in 1948. He went on to study theoretical physics at the University of Wisconsin–Madison under Robert G. Sachs. In 1950, Amdahl and Charles H. Davidson, a fellow PhD student, approached Prof. Harold A. Peterson with the idea of a digital computer. With support from Peterson and electrical engineering professor Vincent C. Rideout, they built a computer of their unique design. Amdahl completed his doctorate in 1952 with a thesis titled 'A Logical Design of an Intermediate Speed Digital Computer' and created his first computer, the Wisconsin Integrally Synchronized Computer (WISC). He then went straight from Wisconsin to a position at IBM in June 1952. At IBM, Amdahl worked on the IBM 704, the IBM 709, and then the Stretch project, the basis for the IBM 7030. He left IBM in December 1955, but returned in September 1960 after working at Ramo-Wooldridge and Aeronutronic. On his return, he became the chief architect of IBM System/360 and was named an IBM Fellow in 1965, and head of the Advanced Computing Systems Laboratory (ACS) in Menlo Park, California. He left IBM again in September 1970 after his ideas for computer development were rejected, and set up Amdahl Corporation in Sunnyvale, California with major financing from Fujitsu. The company manufactured plug-compatible mainframes, shipping its first machine in 1975 – the Amdahl 470V/6, a less expensive, more reliable and faster replacement for the System 370/168.

Reader's Guide

Gene Amdahl's significance lies in his formulation of Amdahl's law, which states a fundamental limitation of parallel computing. At the 1967 Spring Joint Computer Conference, Amdahl, along with three other computer architects, most notably ILLIAC IV architect Daniel Slotnick, engaged in a discussion on future architectural trends. Amdahl articulated his arguments, both orally and in three written pages, on the fundamental physical limitations that he theorized would govern the performance of any special feature or mode introduced to new machines. This set of arguments resulted in two, major and lesser, 'laws' of computer performance regarding sequential versus parallel processing. These arguments continue to this day. His work at IBM as chief architect of the System/360 established a dominant mainframe architecture. By founding Amdahl Corporation, he pioneered the plug-compatible mainframe market. Customers could run S/360 and S/370 applications without buying actual IBM hardware. By 1979, Amdahl Corporation had sold over US$1 billion of V6 and V7 mainframes and had over 6,000 employees worldwide. His later ventures included Trilogy Systems, Andor International, and Commercial Data Servers. He died on November 10, 2015, in Palo Alto, California, from pneumonia, six days shy of his 93rd birthday.

Did You Know?

• Amdahl completed his doctorate at the University of Wisconsin–Madison in 1952 with a thesis titled 'A Logical Design of an Intermediate Speed Digital Computer' and created his first computer, the Wisconsin Integrally Synchronized Computer (WISC).
• He left IBM in December 1955, returned in September 1960 after working at Ramo-Wooldridge and at Aeronutronic, and then quit again in September 1970 after his ideas for computer development were rejected.
• By 1979, Amdahl Corporation had sold over US$1 billion of V6 and V7 mainframes and had over 6,000 employees worldwide.
• At the 1967 Spring Joint Computer Conference, Amdahl articulated his arguments on the fundamental physical limitations of parallel processing in three written pages, which resulted in Amdahl's law.
• He died on November 10, 2015, in Palo Alto, California, from pneumonia, six days shy of his 93rd birthday, and also had Alzheimer's disease in the last years of his life.

From the Plains to the First Computer

Gene Myron Amdahl entered the world on November 16, 1922, in Flandreau, South Dakota, the son of immigrant parents of Norwegian and Swedish descent. After serving in the Navy during World War II, he completed a degree in engineering physics at South Dakota State University in 1948. He went on to study theoretical physics at the University of Wisconsin–Madison under Robert G. Sachs. However, in 1950, Amdahl and Charles H. 'Charlie' Davidson, a fellow PhD student in the Department of Physics, approached Prof. Harold A. Peterson with the idea of a digital computer. Amdahl and Davidson gained the support of Peterson and fellow electrical engineering professor Vincent C. Rideout, who encouraged them to build a computer of their unique design. Amdahl completed his doctorate at UW–Madison in 1952 with a thesis titled 'A Logical Design of an Intermediate Speed Digital Computer' and created his first computer, the Wisconsin Integrally Synchronized Computer (WISC). He then went straight from Wisconsin to a position at IBM in June 1952.

Architect at IBM and the System/360 Era

At IBM, Amdahl worked on the IBM 704, the IBM 709, and then the Stretch project, the basis for the IBM 7030. He left IBM in December 1955, but returned in September 1960 after working at Ramo-Wooldridge and at Aeronutronic. He quit out of frustration with the bureaucratic structure of the organization. In an interview conducted in 1989 for the Charles Babbage Institute, he addressed this: 'Well, what I felt was that with that kind of an organization I'm not going to be in control of what I want to do any time in the future. It's going to be a much more bureaucratic structure. I'll work in one area of it, and that's all I'll get experience in. And I decided that I didn't want to have that kind of life, basically. It wasn't just Dunwell. It was the way the structure was set up; I was going to be a peg-in-a-hole.' On his return, he became the chief architect of IBM System/360 and was named an IBM Fellow in 1965, and head of the Advanced Computing Systems Laboratory (ACS) in Menlo Park, California. He left IBM again in September 1970, after his ideas for computer development were rejected.

The Plug-Compatible Revolution

After leaving IBM in September 1970, Amdahl set up Amdahl Corporation in Sunnyvale, California with major financing from Fujitsu. Competing with IBM in the mainframe market, the company manufactured 'plug-compatible' mainframes, shipping its first machine in 1975 – the Amdahl 470V/6, a less expensive, more reliable and faster replacement for the System 370/168. By purchasing an Amdahl 470 and plug-compatible peripheral devices from third-party manufacturers, customers could now run S/360 and S/370 applications without buying actual IBM hardware. Amdahl's software team developed VM/PE (Virtual Machine/Performance Enhancement), software designed to optimize the performance of IBM's MVS operating system when running under IBM's VM operating system. By 1979, Amdahl Corporation had sold over US$1 billion of V6 and V7 mainframes and had over 6,000 employees worldwide. The corporation went on to distribute an IBM-plug-compatible front-end processor (the 4705) as well as high-performance disk drives, both jointly developed with Fujitsu engineers.

Amdahl's Law and a Life of Reinvention

At the 1967 Spring Joint Computer Conference, Amdahl, along with three other computer architects, most notably ILLIAC IV architect Daniel Slotnick, engaged in a discussion on future architectural trends. Amdahl articulated his arguments, both orally and in three written pages, on the fundamental physical limitations that he theorized would govern the performance of any special feature or mode introduced to new machines. This set of arguments resulted in two, major and lesser, 'laws' of computer performance regarding sequential versus parallel processing. These arguments continue to this day. Amdahl left his eponymous company in August 1979 to set up Trilogy Systems, together with his son Carl, and Clifford Madden. With over US$200 million in funds, Trilogy was aimed at designing a wafer-scale microprocessor for even cheaper mainframes, but the chip development failed within months of the company's $60 million public offering. Trilogy merged into Elxsi in 1985. Amdahl founded Andor International in 1987, which went bankrupt by 1995. He co-founded Commercial Data Servers in 1996, which later changed its name to Xbridge Systems. In November 2004, Amdahl was appointed to the board of advisors of Massively Parallel Technologies. He died on November 10, 2015, in Palo Alto, California, from pneumonia, six days shy of his 93rd birthday. He also had Alzheimer's disease in the last years of his life.