News Service


John Gustafson, Ames Laboratory, (515) 294-9294
Roger Munns, State Historical Society of Iowa, (515) 242- 5194
Skip Derra, News Service, (515) 294-4917


AMES, Iowa -- An authentic working replica of the world's first electronic digital computer will be on public display at the State Historical Society of Iowa from June 18 to September 27. To kick off the stay of the Atanasoff-Berry Computer (ABC) replica, Iowa State will host an alumni reception at the Historical Society from 5 to 7 p.m. on June 17.

John V. Atanasoff, an Iowa State professor of physics and mathematics, and Clifford Berry, a graduate student, built the original computer in the period of 1939-42. The original ABC was never patented and eventually was discarded. The replica was built to honor Atanasoff and Berry.

"The invention of the electronic digital computer is an important piece of Iowa history," said Iowa State University President Martin Jischke. "The ideas of Atanasoff have transformed society and led to one of our most influential modern industries."

The State Historical Society is located at 600 E. Locust, Des Moines. Hours are 9 a.m. to 4:30 p.m. Monday through Saturday, and noon to 4:30 on Sunday. Admission is free.

The desk-sized ABC had faint resemblance to today's personal computers. It weighed 750 pounds, performed 0.06 operations/sec (compared to 10 billion operations/sec in today's computers) 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 original ABC demonstrated several principles that are the basis of modern computing. 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 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."

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.

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 patent for the ENIAC, 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."

Building the ABC replica has taken considerable time and patience as Ames Laboratory and Iowa State engineers, faculty, and students have had to basically retrace the steps originally taken by Atanasoff and Berry. To build an accurate replica, the team took painstaking care in using vintage computer parts, like 1940s vacuum tubes, brushes and card punches.

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.

The replica is a true-to-life version of the original computer, but it is rarely used to solve problems, primarily because it is a very delicate instrument, Gustafson said. The replica recently solved two simultaneous equations with two unknowns, an operation that took about six minutes to complete.

The ABC replica was formally unveiled and demonstrated on Oct. 8, 1997 at the National Press Club in Washington, D.C. Since that time it has toured nine Iowa communities including Mason City, Dubuque, Cedar Rapids, the Quad Cities, Sioux City, and Waterloo.

The ABC replica and the public displays are being financed by public and private donations as part of the ISU Foundation's $300 million capital campaign, Campaign Destiny. 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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