John Atanasoff and Clifford Berry - The First All Electronic Computer

The Atanasoff-Berry Computer

John Atanasoff once said to reporters, "I have always taken the position that there is enough credit for everyone in the invention and development of the electronic computer." 

Professor Atanasoff and graduate student Clifford Berry certainly deserve some credit for building the world's first electronic-digital computer at Iowa State University between 1939 and 1942. The Atanasoff-Berry Computer represented several innovations in computing, including a binary system of arithmetic, parallel processing, regenerative memory, and a separation of memory and computing functions.

Atanasoff’s Early Years  

Atanasoff was born in October 1903 a few miles west of Hamilton, New York. His father, Ivan Atanasov, was a Bulgarian immigrant whose last name was changed to Atanasoff by immigration officials at Ellis Island in 1889. 

After John’s birth, his father accepted an electrical engineering position in Florida where Atanasoff completed grade school and began understanding the concepts of electricity -- he found and corrected faulty electric wiring in a back porch light at the age of nine, but other than that event, his grade school years were uneventful.

He was a good student and had a youthful interest in sports, especially baseball, but his interest in baseball faded when his father purchased a new Dietzgen slide rule to help him at his job. The young Atanasoff became totally fascinated with it. His father soon discovered that he didn't have an immediate need for the slide rule and it was forgotten by everyone -- except young John.

Atanasoff soon became interested in the study of logarithms and the mathematical principles behind the operation of the slide rule. This led to studies in trigonometric functions. With the help of his mother, he read A College Algebra by J.M. Taylor, a book that included a beginning study on differential calculus and a chapter on infinite series and how to calculate logarithms.


Atanasoff completed high school in two years, excelling in science and mathematics. He had decided that he wanted to be a theoretic physicist and he entered the University of Florida in 1921. The university did not offer a degree in theoretic physics so he began taking electrical engineering courses. While taking these courses, he became interested in electronics and continued on to higher mathematics. He graduated in 1925 with a Bachelor of Science degree in electrical engineering. He accepted a teaching fellowship from Iowa State College because of the institution's fine reputation in engineering and sciences. Atanasoff received his master's degree in mathematics from Iowa State College in 1926.

After marrying and having a child, Atanasoff moved his family moved to Madison, Wisconsin where he had been accepted as a doctoral candidate at the University of Wisconsin. The work on his doctoral thesis, "The Dielectric Constant of Helium," gave him his first experience in serious computing. He spent hours on a Monroe calculator, one of the most advanced calculating machines of the time. During the hard weeks of calculations to complete his thesis, he acquired an interest in developing a better and faster computing machine.

After receiving his PhD in theoretical physics in July 1930, he returned to Iowa State College with a determination to try to create a faster, better computing machine.

The First “Computing Machine”

Atanasoff became a member of the Iowa State College faculty as assistant professor in mathematics and physics in 1930. He felt he was well equipped to try to figure out how to develop a way of doing the complicated math problems he had encountered during his doctoral thesis in a faster, more efficient way. He did experiments with vacuum tubes and radio and with examining the field of electronics. Then he was promoted to associate professor of both mathematics and physics and moved to the school’s Physics Building.

After examining many mathematical devices available at the time, Atanasoff concluded that they fell into two classes: analog and digital.

The term "digital" was not used until much later, so he contrasted analog devices to what he called "computing machines proper." In 1936, he engaged in his last effort to construct a small analog calculator. With Glen Murphy, then an atomic physicist at Iowa State College, he built the "Laplaciometer," a small analog calculator. It was used for analyzing the geometry of surfaces. 

Atanasoff regarded this machine as having the same flaws as other analog devices -- accuracy was dependent upon the performance of other parts of the machine. His obsession with finding a solution to the computer problem built to a frenzy in the winter months of 1937. One night, frustrated after many discouraging events, he got in his car and started driving without destination. Two hundred miles later, he pulled onto a roadhouse. He had a drink of bourbon and continued thinking about the creation of the machine. No longer nervous and tense, he realized that this thoughts were coming together clearly. He began generating ideas on how to build this computer.

The Atanasoff-Berry Computer

After receiving a $650 grant from Iowa State College in March 1939, Atanasoff was ready to build his computer. He hired a particularly bright electrical engineering student, Clifford E. Berry, to help him accomplish his goal. With his background in electronics and mechanical construction skills, the brilliant and inventive Berry was the ideal partner for Atanasoff. They worked at developing and improving the ABC or Atanasoff-Berry Computer, as it was later named, from 1939 until 1941. 

The final product was the size of a desk, weighed 700 pounds, had over 300 vacuum tubes, and contained a mile of wire. It could calculate about one operation every 15 seconds. Today, computers can calculate 150 billion operations in 15 seconds. Too large to go anywhere, the computer remained in the basement of the physics department. 

World War II 

World War II started in December 1941 and work on the computer came to a halt. Although Iowa State College had hired a Chicago patent lawyer, Richard R.

Trexler, the patenting of the ABC was never completed. The war effort prevented John Atanasoff from finishing the patent process and from doing any further work on the computer.

Atanasoff left Iowa State on leave for a defense-related position at the Naval Ordnance Laboratory in Washington, D.C. Clifford Berry accepted a defense-related job in California. On one of his return visits to Iowa State in 1948, Atanasoff was surprised and disappointed to learn that the ABC had been removed from the Physics Building and dismantled. Neither he nor Clifford Berry had been notified that the computer was going to be destroyed. Only a few parts of the computer were saved.

The ENIAC Computer 

Presper Eckert and John Mauchly were the first to receive a patent for a digital computing device, the ENIAC computer. A 1973 patent infringement case, Sperry Rand vs. Honeywell, voided the ENIAC patent as a derivative of Atanasoff's invention. This was the source for Atanasoff’s comment that there is enough credit for everyone in the field. Although Eckert and Mauchly received most of the credit for inventing the first electronic-digital computer, historians now say that the Atanasoff-Berry Computer was the first.

"It was at an evening of scotch and 100 mph car rides," John Atanasoff also told reporters, "when the concept came for an electronically operated machine that would use base-two binary numbers instead of the traditional base-10 numbers, condensers for memory, and a regenerative process to preclude loss of memory from electrical failure."

Atanasoff wrote most of the concepts of the first modern computer on the back of a cocktail napkin. He was very fond of fast cars and scotch. He died of a stroke in June 1995 at his home in Maryland.