Iowa State University


John Gustafson, Ames Laboratory, (515) 294-9294
Skip Derra, News Service, (515) 294-4917


WASHINGTON, D.C. -- Iowa State University officials today (Oct. 8) unveiled and operated a full-scale replica of the first electronic digital computer at the National Press Club in Washington, D.C. The replica is a working model of the Atanasoff-Berry computer (ABC), built at Iowa State from 1939 to 1942.

The demonstration took place at 10 a.m. at the National Press Club.

John V. Atanasoff, an Iowa State professor of physics and mathematics, and Clifford Berry, a graduate student, built the computer. The original ABC was never patented and eventually discarded. The replica was built to honor Atanasoff and Berry.

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

"With the original ABC, Atanasoff demonstrated the principles on which modern computing is based," Jischke added. "The ideas of Atanasoff have transformed society and led to one of our most influential modern industries."

The desk-sized ABC has faint resemblance to today's computers. It weighed 750 pounds, performed 0.06 operations/sec (compared to 10 billion operations/sec today) and had a memory storage capacity of 3,000 bits (compared to 100 billion bits today). It also had several noticeable mechanical features including rotating drums (for data storage), a read/write system that recorded numbers by scorching marks into cards as it worked through a problem, and vacuum tubes that flickered as it performed computations.

While slow and cumbersome compared to today's computers, the ABC did demonstrate several principles that are the basis of modern computing. Common computing ideas like the use of the binary system of arithmetic, separate memory and computing functions, internal clock control and the use of circuits for logical addition and subtraction all were first employed by the ABC.

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

Detective work

Building the ABC replica has taken considerable time and patience as engineers, faculty, retired faculty and students have had to basically retrace the steps originally taken by Atanasoff and Berry. The team's primary goal was to make a full-scale, functional computer replica as true to the original as possible. This required painstaking care in using vintage computer parts, like 1940s vacuum tubes, brushes and card punches prevalent of that era, but most which has disappeared as technology evolved.

Because the original was discarded, replica team members had to rely on fragmentary documentation, grainy photographs and the fading memories of those who were part of the original project or close to it. The replica team spent hundreds of hours ferreting out details on how the original operated and in securing authentic parts.

"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 re-spent in building the replica."

This included trips to visit Atanasoff's family and retrieve documentation, getting on loan from the Smithsonian Museum one of the few remaining authentic parts -- a memory drum -- and subjecting it to MRI and x-ray analysis at a local hospital, and jogging the memory of those who as students, helped Atanasoff create the ABC in the late 1930s.

One such person was Robert Mather, a retired physicist living in California, who under the direction of Berry did the wiring of the original ABC. Mather's recollections of the project helped the team immensely as it tried to fill in the gaps of information during the project's construction phase. The result is a replica that has the same look, feel and sound of the original.

"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. "This replica operates the same way the original operated nearly 60 years ago."

Designed to help students

The original ABC was the brainchild of Atanasoff, who was struggling to find a more efficient way to solve large simultaneous equations. Atanasoff's goal was to produce a machine that would lighten the load on his students, who at that time solved such equations through 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 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 computing 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.

"Except for color monitors, a mouse pad and greater speed, he figured out how to do all of the basics way back then," said Gary Sleege, an ABC replica team member.

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.

Forgotten father of computing

The work of Atanasoff and Berry was interrupted by the urgency of World War II. They did not return to their project after the war, and later computing machines soon dwarfed the ABC in size and stature. A 1973 court decision (Honeywell Inc. vs. Sperry Rand Corp. et. al.), which overturned the ENIAC patent, an early computer developed by John W. Mauchly and J. Presper Eckert, stated that the basic ideas of the modern computer came "from one John Vincent Atanasoff."

Atanasoff was given the National Medal of Technology in 1990 by President George Bush in recognition of his pioneering work in computing. But Atanasoff died in 1995, at the age of 91, a relative unknown in the annals of modern computing.

"Atanasoff's breakthrough was the inspiration for the ENIAC and future computing devices," Gustafson said. "Atanasoff did the same thing for computing that the Wright brothers did for aviation. While he didn't start the commercial computer industry, he was the trigger that made it happen."

"Today, computing is almost 10 percent of our Gross Domestic Product, and almost 10 percent of the capital equipment and energy consumption in the U.S. is in computers," Gustafson added. "It is not an exaggeration to say that Atanasoff's work is at the root of trillions of dollars of our economy."

After the unveiling in Washington, D.C., the ABC replica will be returned to Iowa where it will be displayed in several locations. The replica and the public displays are being financed by public and private donations, including major contributions from: John Atanasoff II, ISU alumni Charles and Marge Durham, George and Helen Booth, and Richard Squires; and the Ames Economic Development Commission.

Today, Iowa State is a leader in computer technology. Iowa State provides several programs and projects that are on the cutting edge of computer technology, including the use of advanced computer and communications technologies for education and research, and the exploration and refinement of virtual reality technologies.

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.

Biographies of John Vincent Atanasoff and Clifford Berry

- 30 -

Iowa State homepage

University Relations,
Copyright © 1997, Iowa State University, all rights reserved
Rev ised 10/8/97