Baranger, Walter R. "J. Presper Eckert, Co-inventor of Early Computer, Dies at 76," New York
Times, 7 June 1995, p. B12.
John Prosper Eckert, co-inventor of the mammoth Eniac computer in 1945, believed by many
computer experts and historians to be the first electronic digital computer, died on Saturday in
Bryn Mawr, Pa. He was 76 and lived in Gladwyn, Pa.
The cause was complications from leukemia, a family friend, Thomas Miller, said.
Working under an Army contract in World War II to automate artillery calculations, Mr. Eckert
and Dr. John W. Mauchly, who died in 1980, designed a computer with more than 18,000
vacuum tubes that received instructions through hundreds of cables resembling an old-time
The 30-ton Electronic Numerical Integrator and Computer, or Eniac, was assembled in late 1945
and could complete in 30 seconds a trajectory calculation that took a clerk 20 hours. Stacks of
punched cards provided the data, which at times included work for the Manhattan Project.
Mr. Eckert and Dr. Mauchly founded a company that became a predecessor of the Unisys
Corporation, and Mr. Eckert obtained 87 patents.
Controversy dogged the inventors, in a case in 1973 a Federal court canceled a crucial patent.
The court ruled that the root of the Eniac design was the pioneering work of Dr. John V.
Atanasoff, who had invented a computing device called ABC in the late 1930s's.
Critics said that Dr. Atanasoff had never used his computer for solving practical problems and
that it could solve only a class of problems called simultaneous linear equations.
In a letter to a group of students in 1990, Mr. Eckert called Dr. Atanasoff's work at the
University of Iowa a joke.
"He never really got anything to work," Mr. Eckert wrote. "He had no programming system.
Mauchly and I achieved a complete workable computer system. Others had not."
In any case, only Eniac could confirm design calculations for the atomic bomb.
Although Eniac resembled a scene from a 1950s science-fiction movie, its flashing pink lights,
clicking switches and miles of cables hid a design remarkably similar - in concept at least - to
modern personal computers.
Computers today executive instructions more than 1,000 times faster than Eniac, and their
sophisticated software and desktop designs make them many times more efficient and easy to
use. But the basic process of breaking a number into a series of 1's and 0s and sending the
resulting stream of data through a series of switches called logical "and" and "or" elements, is
shared with Eniac's design.
Mr. Eckert is also credited with having solved the thorny problem of reliability by running the
delicate vacuum tubes, which failed often, at low voltage and avoiding brittle solder connections
by relying on hundreds of old-fashioned plugs. By rearranging the plugs and their cables, the
computer could be reprogrammed to solve a wide variety of problems.
J. Prosper Eckert Jr., as he preferred to be known, was born in Philadelphia. He earned a
bachelor's degree at the Moore School of Electrical Engineering at the University of
Pennsylvania and joined the faculty shortly after graduation.
In 1943 he earned his master's and began collaborating with Dr. Mauchly on solving the problem
of compiling the ballistics tables that artillery officers use to aim their guns.
For centuries artillery officers labored over those calculations, and a small error could be
disastrous. Many variables, including wind, humidity, target elevation, distance and shell weight,
make the calculations extremely complicated and cause the Army to issue volumes of
Mechanical calculators helped. But the Army spent much of World War II looking for a way to
avoid recalculating thousands of tables whenever even small changes were made to the artillery.
In addition, the Manhattan Project severely strained even the most accurate mechanical
calculators, which were Rube Goldberg devices that used motors, generators, photo-electric cells
and vacuum tubes.
Eniac was the answer to both problems, and it was not unplugged until 1955.
In 1946, Mr. Eckert and Dr. Mauchly founded the Electronic Control Company and were
co-developers of the Biniac and Univac computers. Their successor business,s the
Eckert-Mauchly Computer Corporation, was sold to the Remington Rand Corporation, which,
after a series of mergers and name changes, became Unisys.
Mr. Eckert received an honorary doctorate from the University of Pennsylvania in 1964. In 1968,
President Lyndon B. Johnson awarded him a medal for his work as co-inventor of the computer.
Mr. Eckert retired from Unisys in 1989, but continued to be a consultant.
Surviving are his wife, Judith, of Gladwyn; a daughter, Laura E. Phinney, and three sons, John P.
Eckert 3rd, Gregory A. Eckert and Chris C. Eckert.