Atanasoff–Berry computer

The Atanasoff–Berry computer (ABC) was the first automatic electronic digital computer. It was created during a time when technology was still developing, which limited what it could do. Even though it couldn't be changed to perform different tasks like later computers, it played an important role in the history of computing.

One big reason the ABC matters is that it was the first machine to use vacuum tubes for doing arithmetic calculations. Before this, computers used slower methods that took much more time. This idea of using tubes helped make computing faster and influenced later machines.

Other early computers, like Konrad Zuse's Z1 computer and the Harvard Mark I, used different, slower methods. Even the Colossus computer from a few years later, which was able to be programmed, used similar tube technology first tried in the ABC. So, the Atanasoff–Berry computer was an important step in making the fast, electronic computers we use today.

Overview

The Atanasoff–Berry computer was created in 1937 by John Vincent Atanasoff, a professor at Iowa State College, and his student Clifford Berry. It was made to solve math problems with straight-line answers and was tested successfully in 1942. However, some parts of it did not work perfectly, and work stopped when Atanasoff left for World War II.

This early machine introduced ideas used in today’s computers, like using two-number math and electronic parts to switch on and off. But because it could only do one specific job and could not change its tasks, it is different from computers we use today. The importance of this machine became known much later, especially during discussions about who made the first electronic computer.

Design and construction

The Atanasoff–Berry computer was created by John Atanasoff and Clifford Berry between 1939 and 1942. It was built in the basement of the physics building at Iowa State College. This machine used vacuum tubes and capacitors to perform calculations, which was new at the time. It could do about 30 additions or subtractions each second.

Unlike later computers, the Atanasoff–Berry computer could not be programmed to do different tasks. It needed a person to set it up for each problem. It could only solve small problems directly and used paper sheets to hold bigger results in between steps. People used special cards to give it information and read the answers from a display on the machine.

Function

The Atanasoff–Berry computer, or ABC, was made to solve a special kind of math problem called systems of simultaneous linear equations. It could handle problems with up to 29 equations, which was very challenging at the time. This type of problem was becoming more common in physics, where John Atanasoff worked.

The machine could take two equations with up to 29 variables and remove one of the variables. This step had to be done by hand for each equation, making the problem smaller each time. This process was repeated until only one equation was left. George W. Snedecor, the head of Iowa State's Statistics Department, was likely the first to use an electronic digital computer to solve real math problems, and he sent many problems to Atanasoff for the ABC to work on.

Patent dispute

In 1947, two scientists named J. Presper Eckert and John Mauchly applied for a patent for a digital computing device called the ENIAC. This surprised John Atanasoff, because another scientist, John Mauchly, had seen Atanasoff’s earlier machine, the ABC, in 1941. Some people thought Mauchly’s work was based on Atanasoff’s ideas, but Mauchly said it wasn’t.

Later, a company called Honeywell tried to cancel the ENIAC patent, saying the ABC was an earlier example. In 1973, a court decided the ENIAC patent was not valid because it used ideas from Atanasoff’s computer. The judge said Eckert and Mauchly did not invent the electronic digital computer first—they got their ideas from Atanasoff.

Replica

The original Atanasoff–Berry computer was taken apart in 1948 when the university turned its basement into classrooms. Almost all its parts were thrown away, except for one memory drum.

In 1997, a team of researchers built a working copy of the Atanasoff–Berry computer. They were led by Delwyn Bluhm and John Gustafson from the Ames Laboratory at Iowa State University. This copy cost $350,000 to make, which would be about $702,000 today. It was first shown at Iowa State University and later moved to the Computer History Museum.