Iowa State University

Joel Snow, IPRT, (515) 294-6551
Del Bluhm, Ames Laboratory, (515) 294-3757
John Gustafson, Ames Laboratory, (515) 294-9294
Skip Derra, News Service, (515) 294-4917


PITTSBURGH -- Iowa State University officials today (Nov. 18) unveiled a full-scale replica of the first electronic digital computer during the Supercomputing '96 Conference in Pittsburgh. When completed, the replica will be a working model of the Atanasoff-Berry Computer (ABC), built at Iowa State during the period of 1939-1942.

John V. Atanasoff, an Iowa State professor of physics and mathematics, and Clifford Berry, a graduate student, built the computer. It was never patented and eventually discarded. The replica is being built to honor the legacy of these two computing pioneers.

"We feel it is of utmost importance to build the replica and honor these two pioneers who set the course of modern computing with their machine," said Iowa State University President Martin Jischke. "What better way to honor their genius than to rebuild the first electronic digital computer."

"John Atanasoff's ABC has an especially significant place in the history of supercomputing, foreshadowing some of the most important concepts used in contemporary advanced scientific computers, including parallel processing," added James Kasdorf, vice chair of Supercomputing '96. "The many novel and groundbreaking advancements made by Dr. Atanasoff truly led the way to today's computer industry."

The Supercomputing '96 Conference runs from Nov. 17-22 at the Lawrence Convention Center in Pittsburgh. It is co-sponsored by the IEEE Computer Society and the Association for Computing Machinery. The ABC replica will be on display at a special history exhibit (booth 261) during the conference.

Building the ABC replica has taken considerable time and patience as technicians, engineers, faculty, retired faculty and students have had to basically retrace the steps originally taken by Atanasoff and Berry. Replica team members have had to rely on fragmentary documentation, grainy photographs and fading memories of those who were part of the original project or close to it.

"We thought it would be easier to build the ABC today than it was in 1939," said Del Bluhm, director of the replica project and manager of R&D engineering at the Ames Laboratory. "But we found that we had to re-engineer and re-create what they did in the 1930s, so all of the hours they spent in design and building the original, we are re-spending in building the replica."

"What's amazing about the replica is that it's faithful to the original, down to the vacuum tubes, gears and materials used to make the distinctive drums," added Joel Snow, director of ISU's Institute for Physical Research and Technology. "When the replica is completed it will operate the same way the original operated nearly 60 years ago."

The original ABC was the brainchild of Atanasoff, who was struggling to find a more efficient way to solve large simultaneous equations. In Atanasoff's time, such equations were solved by a tedious process using a mechanical calculator.

In 1934, Atanasoff began exploring some of the basic principles he would later use in his computing device. Working in the unfinished basement of Iowa State's Physics Building, Atanasoff and Berry assembled a stunning array of advances in computer technology. Many of their ideas are the basis of modern computers today.

For example, the ABC was the first to employ a binary system of arithmetic, have separate memory and computing functions, have a regenerative memory, use electronic amplifiers as on- off switches, perform parallel processing, use circuits for logical addition and subtraction, have clocked control of electronic operations and have modular design construction.

"The architecture of the original is ingenious," said replica team member and Ames Laboratory computational scientist John Gustafson. "There were so many unprecedented innovations in that cabinet that one hardly knows where to start listing them for importance."

While designed to solve 29 simultaneous equations with 29 unknowns, an operation that would take 50 hours of ABC's computing time alone, it is believed that the original solved five equations with five unknowns. But the significance of the ABC was the course it set for subsequent computing machines and its role in a landmark technological revolution of the 20th century.

The replica team -- which includes scientists and engineers from the Ames Laboratory, the Institute for Physical Research and Technology and ISU -- plans to finish work and test the replica by the spring of 1997. An official unveiling and demonstration will take place this spring.

Ames Laboratory, a member of Iowa State University's Institute for Physical Research and Technology, is a U.S. Department of Energy research laboratory operated by the university for the federal government.

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