Electronic Design
John Atanasoff and Clifford Berry: Inventing The ABC,  A Benchmark Digital Computer

John Atanasoff and Clifford Berry: Inventing The ABC, A Benchmark Digital Computer

Atanasoff and Berry (2010)



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A good way to start a virtual fistfight among technology historians is to ask them to name the first digital electronic computer. Many would undoubtedly mention the University of Pennsylvania’s ENIAC, created by J. Presper Eckert and John Mauchly between 1943 and 1946. Others would make a strong and perhaps definitive case for the Atanasoff-Berry Computer (ABC), which was developed at Iowa State University between 1937 and 1942.

The story of ENIAC’s development has been told many times. ABC’s history is heard far less often, however. That’s a shame, because it’s a tale with lessons that still resonate in today’s era of cutthroat competition among smart-phone, tablet computer, cloud computing, and other technology innovators.

A Series of Firsts
Created by John Vincent Atanasoff, an Iowa State mathematics and physics professor, and graduate student Clifford Berry, ABC certainly had many of the features one would expect to see in a digital electronic computer, including a DRAM-like memory, parallel processing, and separate memory and computing functions.

While ABC lacked ENIAC’s general-purpose functionality—it was limited to solving systems of linear equations—the machine was nevertheless the first to use binary digits to represent data and to perform all calculations electronically rather than mechanically. (Incidentally, neither ENIAC nor ABC could use a stored program. That capability arrived in 1949 with a British computer, EDSAC.)

ABC’s development began in 1937, when Atanasoff was looking for a way to accelerate work on the complex mathematical problems he and his graduate students were struggling to solve on crude analog desktop calculators. According to his son, John V. Atanasoff II, Atanasoff liked to think while driving, often at high speeds. One evening, while taking a break in a roadside tavern, he was struck by the idea of a system combining regenerative memory and logic circuits.

A couple of years and $650 later, Atanasoff and assistant Berry completed a working ABC prototype. The device featured a pair of rotating drums that used charged and uncharged capacitors to create temporary memory. Data was entered via punch cards. The system used vacuum tubes for arithmetic logic functions—a first. For the next several years, ABC was used for computational tasks in a variety of scientific fields.

In September 1942, with World War II underway, Atanasoff left Iowa State to conduct defense research at the Naval Ordnance Laboratory in Washington, D.C. Berry, who received an MS in physics in 1941, departed to take a defense job with Consolidated Engineering Corp. (CEC), in Pasadena, Calif.

Atanasoff’s defense work would ultimately lead to a lengthy career with the federal government. In 1952, he left government service to co-found the Ordnance Engineering Corp., a research and engineering company located in Rockville, Md.

The firm was sold to Aerojet General Corp. in 1957, and Atanasoff managed Aerojet’s Atlantic division from 1957 to 1959 and was a vice president from 1959 to 1961. In 1961 he started another company, Cybernetics Inc., in Frederick, Md., which he ran for 20 years.

Berry, meanwhile, remained with CEC for nearly two decades, forging a career in mass spectrometry, vacuum, and electronics research. He left the firm in 1963, shortly before his death.

Patent Dispute
In the years immediately after the war, computer progress accelerated quickly. On June 26, 1947, Eckert and Mauchly became the first researchers to file a patent application for a digital computer device, ENIAC. The patent filing surprised Atanasoff.

“He thought \\[Iowa State\\] was applying for the patent of the ABC—but they didn’t want to spend the money,” recalls John V. Atanasoff II. Atanasoff was soon drawn into a growing legal dispute over who, if anybody, owned the technology foundation for electronic digital computing.

“He became fully involved \\[in litigation\\] when the ENIAC patents were filed, and IBM, Honeywell, and Control Data Corp. approached him,” Atanasoff’s son says. The computer makers, looking to escape steep licensing fees, threw their support behind ABC in an effort to invalidate the ENIAC patents.

Many historians have observed over the years that ABC was a major inspiration for ENIAC. Atanasoff’s son states the relationship more bluntly: “John Mauchly visited Iowa State in 1940-41 and illegally borrowed some of the ideas in the ENIAC development and patent.”

After years of threats and counter-threats, the final legal battle was launched when Honeywell sued ENIAC patent holder Sperry Rand on May 26, 1967. The trial lasted until October 19, 1973, when the main ENIAC patent was declared invalid.

“Eckert and Mauchly did not themselves invent the automatic electronic computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff,” wrote U.S. District Judge Earl R. Larson in his summary and judgment.

The court decision, which was never appealed, vindicated Atanasoff and Berry, at least in the eyes of the law. Some historians, however, continued questioning ABC’s standing as the first electronic digital computer.

The machine wasn’t suitable for general-purpose calculations, some historians say. Also, it couldn’t reach electronic-level speeds (due to the rotating drum). It was error-prone when handling large systems of equations. And, it had a poorly developed input/output system. On the other hand, ENIAC performed well, given the limitations imposed by pre-solid-state components, and experienced a long and adaptable service life.

Atanasoff’s son notes that his father had mixed feelings about the ruling. “My dad was pleased with the court decision, but was disappointed that many people did not accept the verdict,” he says.

Yet while historians continue to quibble over ABC’s precise place in history, virtually none deny the fact that the machine marked a major milestone in computer evolution. In fact, many of ABC’s basic concepts and design innovations live on in today’s high-speed, multiprocessor, virtualized computers.

At the time of Berry’s death, in 1963, massive mainframes still ruled the computer universe. Yet Atanasoff lived until 1996, long enough for him to see his pioneering work lead to home PCs, network servers, and the Internet.

A Lasting Legacy
Atanasoff received numerous honors during his life, culminating in the United States National Medal of Technology, which President George H.W. Bush awarded him in 1990. “As his son, I recognized he was brilliant, ingenious, very hard working, and dedicated to his goals,” the younger Atanasoff says. “He was an amazing man.”

Perhaps owing to his early death and its cause, which was suicide, as well as his graduate student status, Berry’s contributions to ABC have received relatively little recognition. Yet Atanasoff during his lifetime easily shared the credit for ABC’s success with his partner.

“The machine succeeded rapidly because Clifford Berry had this ease in working with materials,” Atanasoff recalled in a 1972 oral history interview with the Smithsonian Institution. “The machine would never have gotten in the position it was without Clifford Berry’s \\[work\\].”

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