John Mauchly and John Eckert

For more than 25 years ENIAC was considered the first digital electronic computer in the world. As late as the beginning of the 1970s this assertion was proved false. First, by the famous trial Sperry Rand Corporation vs. CDC and Honeywell, which started in 1971, and later by the information, which began to emerge about the Colossus computer. At present, it is clear, that first was (prototype built in 1939) the ABC computer of Atanasoff and Berry and the second was the Colossus Mark I computer (build in 1943) of Newmann and Flowers.

Rather eloquent was the finding of the judge of the abovementioned lengthy court trial (it lasted 135 working days, filled more than 20000 pages of the transcript with the testimony of 77 witnesses), the Judge in the U.S. District Court in Minnesota Earl R. Larson, distributed on 19 October 1973 —Mauchly’s basic ENIAC ideas were derived from Atanasoff, and the invention claimed in ENIAC was derived from Atanasoff. In extensive findings, Judge Larson declared: Eckert and Mauchly did not themselves first invent the automatic electronic digital computer, but instead derived that subject matter from one Dr. John Vincent Atanasoff. Furthermore, Judge Larson had ruled that Mauchly had pirated Atanasoff’s ideas, and for more than thirty years had palmed those ideas off on the world as the product of his own genius.

Despite this controversy and Mauchly’s shameful display during the trial (he spoke slightingly for Atanasoff and his computer and changed his testimony under oath three times because the documents and other witnesses’ evidence were against him), the ENIAC computer played an extremely important role in the history of electronic computers.

John Mauchly for the first time met a serious computational problem in 1938 while preparing an article for meteorological data analysis for the Journal of Terrestrial Magnetism and Atmospheric Electricity. This article, however, was rejected, as one of the reasons for the rejection was relying on too short a period of data analysis. This rejection prompted Mauchly to begin early experiments with digital electronic computing circuitry. His two years as an undergraduate in an electrical engineering department no doubt fueled this new twist in his research. His resources were small, as was the scale of these trials. Among the circuits that he built were basic elements such as a flip-flop, which could essentially store the “1s” and “0s” that make up the information stored by all digital computers. Mauchly built some of the circuits using neon bulbs rather than the more expensive vacuum tubes, which meant that they did not have the full performance of vacuum tube circuitry. Thus Mauchly was beginning to figure out the basic concepts behind electronic computing circuitry himself.

During WWII the US Army (as well as all other armies) faced a very nasty problem with the computation of firing tables for artillery. Since the factories were producing new long-range guns and a gunner often couldn’t see his target over the hills, he relied on a booklet of firing tables to aim the artillery gun. How far the shell traveled depended on a host of variables: the wind speed and direction, humidity and temperature of the air, elevation above sea level, the ground, etc. Even the temperature of the gunpowder mattered. A typical gun required a firing table with five hundred different sets of conditions. Each new gun, and each new shell, had to have new firing tables, and the calculations were done based on test firings and mathematical formulas. The USA Army used a staff of 176 people (so-called computers) in Aberdeen near Philadelphia and in Moore School, doing the calculating, using desk calculators with push buttons and a large handle to pull to complete each arithmetic operation. Besides that, they used two differential analyzers (the differential analyzer was a mechanical analog computer, designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration), nevertheless, they need more than a month to produce a complete firing table with all the trajectories needed, which was unacceptable. Aberdeen was falling far behind in its firing table responsibility, and guns were being delivered to Europe and Africa that were essentially useless because they could not be aimed. In 1941, the US Army’s Ballistic Research Laboratory, responsible for producing firing tables, had made the Moore School into an auxiliary of its computing section. The Moore School performed its work using both analog and numerical methods, the former based on the use of the differential analyzer, and the latter was carried out by a separate group of human computers assembled by the Moore School.

Thus Lieutenant Herman Goldstine, a young 29 years old Ph.D. and professor of mathematics at the University of Michigan, had been put in charge of the operation in Penn and ordered to get the tables completed faster, no matter what. Soon Goldstine began calculating the impossibility of the task. The demand for tables was so great, they would never be finished before the guns reached combat. Goldstine sent his wife, Adele, a mathematician herself, on cross-country recruiting trips to seek out more female math majors at colleges, but there was only a handful to be found. He prodded technicians to run the Differential Analyzer as much as possible, but it was prone to breakdowns. Then one day, a graduate student at Penn asked Goldstine if he had heard of an idea that a newly hired professor, John Mauchly, had been spouting. It seemed so silly that the Penn faculty had ignored it. Mauchly had wanted to make an electronic calculator, that could take the place of all the computers.

In August 1942, Mauchly produced a seven-page memorandum—The Use of High-Speed Vacuum Tube Devices for Calculation. In this document he touted the advantage that his machine would be far more accurate than existing mechanical devices, his main selling point was speed—A great gain in the speed of the calculation can be obtained if the devices that are used employ electronic means for the performance of the calculation, because the speed of such devices can be made very much higher than that of any mechanical device. Mauchly’s memorandum, however, was ignored by Penn’s deans, but circulated among his colleagues and students and most importantly to a young graduate student, J. Presper Eckert, who was undoubtedly the best electronic engineer in the Moore School.

When Goldstine tracked Mauchly down and inquired about his idea, he couldn’t believe his good fortune. He immediately realized the army was the way to get his machine built. Suddenly, John Mauchly became an expert on firing tables. He would venture down to the basement, where the Differential Analyzer was located, and tantalize the firing-table workers with questions like, Wouldn’t it be great if you had a machine that would do that in twenty seconds?

Goldstine quickly grasped Mauchly’s idea to make the Differential Analyzer electronic, replacing all the gears and wheels with electronic counters, driven by pulses of electricity and he persuaded his immediate superiors to take the idea to top army brass and ask for funding. On 9 April 1943, Goldstine presented Mauchly and Eckert to Colonel Leslie Simon, director of the Ballistics Research Laboratory, and Oswald Veblen, a renowned mathematician and technical adviser to the army and they agreed to fund the project. The army gave the University of Pennsylvania a development contract and an initial appropriation of $61700 for the first six months of work on what Eckert and Mauchly called the Electronic Numerical Integrator. The name was later changed to Electronic Numerical Integrator and Computer (ENIAC).

The work on the computer began in June 1943, with Eckert as chief engineer and Mauchly as his consultant. In the beginning, the key role was played by Mauchly, but later on, after settling the initial ideas, the leadership was transferred to Eckert, who was a genius engineer, and Goldstein, who was appointed as a representative of the Army and maintained mathematical and organizational tasks. ENIAC was finished too late for the purpose for which it was built—by the fall of 1945, just as the war had ended, and presented to the public in February 1946. It had taken 200000 man-hours of work and cost some $487000. What the army got was a thirty-ton monster, that filled a room 10 by 15 m. It had 30 different units, including its twenty accumulators, arranged in the shape of U, sixteen on each side, and eight in the middle, all connected by a ganglion of heavy black cable as thick as a fire hose. It could perform 5000 addition cycles a second and do the work of 50000 people working by hand. In thirty seconds, ENIAC could calculate a single trajectory, something that would take twenty hours with a desk calculator or fifteen minutes on the Differential Analyzer. ENIAC required 174 kilowatts of power to run. It contained 17468 vacuum tubes, 1500 relays, 500000 soldered joints, 70000 resistors, and 10000 capacitors-circuitry. The clock rate was 100 kHz. Input and output via an IBM card reader and card punch and tabulator.

The units of the ENIAC can be loosely grouped into five categories: arithmetic (general purpose and dedicated units), global control units, memory, I/O units, and busses (trunks). The lower scheme shows a functional organization diagram of the ENIAC. The units concerned mainly with arithmetic operations are 20 accumulators (for addition and subtraction), a multiplier, and a combination of a divider and a square rooter. Numbers are introduced into the machine by means of a unit, called the constant transmitter, which operates in conjunction with the IBM card reader. The reader scans standard punched cards (which hold up to 80 digits and 16 signs) and cause data from them to be stored in relays, located in the constant transmitter. The constant transmitter makes these numbers available, as they are required. Similarly, results may be punched on cards by the ENIAC printer unit operating in conjunction with the IBM card punch. Tables can be automatically printed from the cards by means of an IBM tabulator.

The accumulators (arithmetic units) of ENIAC consisted of electronic ring counters, formed by a linear array of flip-flops. Since ENIAC was a decimal machine, capable of handling numbers of decimal digits for each plus sign, each accumulator contained 10 ring counters each of 10 stages, and a 2-stage ring counter for the sign of the number. When a number was received by an accumulator, it was added to the prior contents of that unit. The subtraction was performed as a type of addition through the representation of negative numbers by complements.

An addition or subtraction took 200 microseconds, a multiplication required some 3 milliseconds. To achieve this speed, it built into it an electronic device, which stored the multiplication table. The most complex operation was division, which required some 30 milliseconds, similar to the square root.

Various units of the ENIAC communicate with each other over the data, program, and synchronization busses (also called trunks). Digit trunks are carried in trays that are stacked on top of each other, allowing for multiple connections. Digit trays can also be used over again in the course of a program. Only one accumulator can transmit data on a digit trunk at any one time, but multiple accumulators can listen in. In addition to the regular transmission of digits over digit cables/trunks, adapters can be used to change the digit place between the transmitting and receiving accumulator. As an example, a shifter adapter is used to multiply a number by a power of 10, while a delete adapter is used to eliminate the pulses of one or more places of the transmitting number.

The ENIAC could be programmed to perform complex sequences of operations, which could include loops, branches, and subroutines. The task of taking a problem and mapping it onto the machine was quite complex, and usually took weeks. Six women were chosen from among the several hundred human computers to work on ENIAC, making them the world’s first computer programmers. Programming the ENIAC was very different from what we consider programming on a modern, stored-program computer. The data-flow architecture of the ENIAC requires setting switches by manipulating its switches and cables and making connections between units (see the lower photo). Programming consists of the following steps.
1. First, the problem to be solved needs to be described by a set of mathematical equations, such as total or partial differential equations.
2. Then, the equations are broken down into basic mathematical operations that the ENIAC is capable of executing.
3. Also, one needs to plan for the storage of numerical data. For each arithmetical operation, one needs to set up a program control and make connections between the program control I/Os.
4. Finally, the individual programs are tied together into a program sequence, so that a collection of programs is automatically stimulated upon completion of another set of programs.

Mauchly and Eckert applied for a patent on the ENIAC in 1947 (but the USA patent No. 3120606 was granted as late as 4 February 1964). By then, they had resigned from the Moore Engineering School and had begun their own corporation, the Eckert and Mauchly Computer Corporation. They assigned their patent to their corporation, where they developed the first commercial computer, the UNIVAC. Eckert took care of the engineering functions, and Mauchly ran the business. Neither Mauchly nor Eckert, however, was a good businessman. They eventually ran into financial troubles, and in 1950 sold their company along with their computer patents to Remington Rand. Sperry Rand later bought out Remington. Mauchly worked for Remington and Sperry until 1959 when he left to form his own consulting corporation, Mauchly Associates.

Biography of John Mauchly and John Eckert

John William Mauchly was born on 30 August 1907, in Cincinnati, Ohio, in the family of Sebastian J. and Rachel Scheidemantel Mauchly (1878-1960). The father, Sebastian Jacob Mauchly (1878-1928), whose grandparents (Pankratius Fidelis Mauchle and Sophia Schochli) had emigrated to Ohio from Zürich, Switzerland, in 1839, was a high-school science teacher, who went on to receive his Ph.D. in physics from the University of Cincinnati. When John was 8, his father received an appointment as a chief physicist at the Carnegie Institute of Washington, D.C., in the newly established Department of Terrestrial Magnetism. This position, and his apparatus, enabled John’s father to discover the diurnal variation in the Earth’s magnetic field, a discovery for which he secured a considerable reputation.

Yet, if a commitment to science was one of the early elements of John’s socialization, he was also moved by the heady materialism of the 1920s. Although scientists in the United States were not yet a class unto their own, membership in an elite institution such as the Carnegie Institution enabled the Mauchlys to enjoy a middle-class lifestyle, they carved out for themselves in a modest four-bedroom, one-bath frame house in the comfortable suburb of Chevy Chase, Maryland. John’s mother, Rachel Mauchly, was a strong woman, who enjoyed the gay lifestyle of the 1920s. She had attended the regular meetings of the local Women’s Club, hosted some of its luncheons, and held informal hen parties with her new friends and social acquaintances. The mother worked hard to cultivate her son’s interests. She arranged for the obligatory piano lessons, chided him for his penmanship, and saved up for the annual family vacation out at the Jersey shore.

His father’s occupation afforded Mauchly a decent education, beginning with his schooling at the McKinley Technical High School in downtown Washington. Yet in grade school, Mauchly demonstrated his talent in construction and earned money installing electric bells in place of mechanical bells. When neighbors had trouble with their wiring, they called John Mauchly. He earned near-perfect scores in high school, was a whiz at math and physics, and was editor of the school paper his senior year (1925). Still, in balancing his school work with tennis matches and walks through the woods, or one of Edgar Allen Poe’s ghost stories read in the dark among friends, Mauchly led a reasonably comfortable existence of an upper-middle-class youth. His academic achievements brought him the Engineering Scholarship of the State of Maryland, which enabled him to enroll at Johns Hopkins University in the fall of 1925, as an undergraduate in the Electrical Engineering program.

There were problems in his family, however. During one of his scientific voyages (sometime before 1925), Sebastian Mauchly contracted a chronic illness. Unwilling to let go of his scientific work, he continued to work excessive hours, which only made his condition worse. Between 1925 and 1928, Mauchly received postcards from the New Jersey shore, where his family went to help his father’s convalescence.

During his freshman year at Johns Hopkins University, Mauchly complained to his father about the General Engineering course, which attempted to provide a more theoretical foundation for engineering. By the end of his second year, Mauchly began to feel that engineering was too mundane. In 1927 he made use of a special provision that allowed outstanding students to enroll directly in a Ph.D. program before completing their undergraduate degrees and transferred to the graduate physics program of the university.

Mauchly’s father passed away on Christmas Eve of 1928. A series of scholarships permitted Mauchly to continue with his studies after his father’s death. Mauchly submitted his dissertation on “The Third Positive Group of Carbon Monoxide Bands” to the faculty of Johns Hopkins University in 1932.

Mauchly eventually accepted a teaching position in physics at Ursinus College, a small, liberal arts college located on the outskirts of Philadelphia, where he taught introductory physics courses. However, the circumstances at Ursinus did not suit the research interests to which he had been so thoroughly conditioned. Physics itself was changing, and by the 1930s the leading laboratories in the country were equipped with accelerators, spectrometers, and other instruments beyond the resources of many state universities, let alone an individual professor working at a liberal arts college. Mauchly made some attempts to develop analog electronic instruments suitable for specific lines of research. He also discovered a wealth of meteorological data, which by the 1930s were being collected from field stations located all around the globe. Such data were available in tabular form and were transportable to an isolated researcher. Their analysis, however, required extensive calculations. Mauchly actually sought more generally to improve calculating instruments, thinking as much about the needs of his students as his own research. This preoccupation with making calculations quicker and easier led Mauchly towards calculating machines. He purchased a second-hand Marchant calculator to carry out the calculation of molecular energy levels that could be extracted from meteorological data.

In the summer of 1936, Mauchly decided to take up a position as a temporary assistant physicist and computer at the Carnegie Institution’s Department of Terrestrial Magnetism. He accepted a position as a glorified human computer, working for his father’s former supervisor. At the end of the third summer, Mauchly submitted his work for publication in the Journal of Terrestrial Magnetism and Atmospheric Electricity. This article, however, was rejected, as one of the reasons for the rejection was relying on too short a period of data analysis. Thus Mauchly starts thinking about finding a means of performing a greater volume of computation. He first turned to the resources offered by the National Youth Administration, a Depression-era agency that allowed him to hire students to work as human computers. Simultaneously, Mauchly turned to mechanical solutions. One aspect of this was Mauchly’s decision to examine tabulating machines, a machine that was used to routinely compute statistics in the social sciences.

This new interest and his encounter with John Atanasoff eventually in 1941 led Mauchly to the Moore School of Electrical Engineering, part of the University of Pennsylvania. The Moore School stood at the heart of a strong regional electrical industry that had grown with the popularity of radio, telephony, and other electronic technologies. With the prospects of war looming, the military began to seek young engineers trained to operate the electronic weapons and communications systems that were becoming an increasing part of U.S. armaments. The Moore School stepped forward to accept a contract from the U.S. Army to teach a special ten-week course on Electrical Engineering for Defense Industries directed to students with a degree in mathematics or physics. Thus Mauchly agreed to study electrical engineering at the Moore School, despite of the fact, that he had an opportunity to take up a defense training job at another college for big money and badly needed this money. It was there he met Eckert and they began their famous collaboration. The Moore School had already developed one of the most advanced electro-mechanical computational devices in the world, the differential analyzer. The differential analyzer was a mechanical analog computer designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration. At the beginning of the war, the United States Army had awarded the school a contract to compute the tables of trajectories for artillery shells. Both Mauchly and Eckert became deeply involved in this project. This project increased Mauchly’s interest in electronic computation and step by step led him to the creation of ENIAC.

In 1947 Mauchly and Eckert resigned from the Moore Engineering School and began their own corporation, the Eckert and Mauchly Computer Corporation. Later on, they developed the computers BINAC and UNIVAC. Eckert took care of the engineering functions, and Mauchly ran the business. Neither Mauchly nor Eckert, however, was a good businessman. Mauchly was a very easygoing and jovial man, but he was also rather unconventional. When he and Eckert visited IBM and its famous president, Thomas Watson, Sr., Mauchly flopped down on the couch and put his feet up on the coffee table. Eckert and Mauchly eventually ran into financial troubles, and in 1950 they sold their company along with their computer patents to Remington Rand. Sperry Rand later bought out Remington. Mauchly worked for Remington and Sperry until 1959 when he left to form his own consulting corporation, Mauchly Associates. In 1968, he founded a second computer consulting corporation, which he called Dynatrend.

Mauchly was a dashing person with brown hair and hazel eyes. Standing about six feet and weighing 180 pounds, the long-limbed Mauchly was well read, soft-spoken, and whimsical man. He had married Mary Augusta Walzl, a mathematician, in 1930. They had a son, James, born in 1935, and a daughter, Sidney, born in 1939. Unfortunately in September 1946, while they were swimming in the Atlantic, Mary was swept out to sea and drowned. On 7 February 1948, Mauchly married Kathleen R. McNulty, who had been one of the programmers on the ENIAC. He had five more children with her, four daughters and a son. Mauchly suffered all his life from a hereditary genetic disease called hemorrhagic telangiectasia, which caused anemia, bloody noses, and internal bleeding, among other symptoms. In his later life, he had to carry around oxygen to breathe properly.

Despite his family, business, and court problems, Mauchly had a successful career. Whatever the various turns in his life, he designed and oversaw the development of the first large-scale general-purpose electronic computer. He created a start-up venture which he eventually sold at a profit to the company that went on to manufacture his computer. His work as a consultant was also successful. Moreover, Mauchly received academic recognition for his contributions: the Potts Medal of the Franklin Institute in 1949, the John Scott Award in 1961, and the Harry Goode Medal of the American Federation of Information Processing Societies in 1966.

Mauchly retired to the quiet suburb of Ambler, Pennsylvania, just outside of Philadelphia. He died on 8 January 1980, of complications from an infection.

John Adam Presper Eckert Jr. (called Pres) was born in Philadelphia on 9 April 1919, to John Presper Eckert and Ethel Hallowell Eckert. His father was the rich real estate developer and self-made millionaire John Eckert. Eckert Jr. was an only child and was raised in a large house in Philadelphia’s Germantown section.

But Pres was more than just a child who had been driven to the prestigious William Penn Charter School by a chauffeur. He was a genius in his own right. As early as five-year-olds he was sketching radios and speakers. At age twelve, he won a Philadelphia science fair with a water-filled tub and a sailboat that he could control with a steering wheel hooked to magnets laid at the bottom of a homemade pond. This invention was patterned after an amusement he had seen in a park in Paris, and it was so sophisticated, that it had a rheostat, which could control electric current to the magnets, enabling him to drop one boat and pick up another for maneuvering in the four-by-six-foot pond. At age fourteen, he replaced a vexatious battery-powered intercom system in one of his father’s high-rise apartment buildings with an electrical system. He built radios and phonograph amplifiers and earned pocket money installing sound systems for schools, nightclubs, and special events. He even was hired by West Laurel Hill Cemetery in Merion to build a music system that masked the unnerving sound of gas burners in the nearby crematorium.

In high school, he spent afternoons hanging out in the Chestnut Hill research laboratory of Philo Taylor Farnsworth, who had demonstrated a working model of a television system in 1927. On the math portion of the College Board examination, Pres was placed second in the country. He wanted to go to the center of USA scientific research—Massachusetts Institute of Technology (MIT) and was easily accepted. But his mother couldn’t bear the thought of her only child leaving home, and his father wanted him to attend business school, so they enrolled Pres at the Wharton School of Business at the University of Pennsylvania. Feigning tight finances because of the depression, they even required Pres to live at home and commute to the downtown campus.

Bored in business classes, Pres soon tried to transfer to the physics department, but no spaces were available. Finally, he decided to transfer to the Moore School of Electrical Engineering of the University of Pennsylvania, where he enrolled in 1937.

At Moore School, Eckert distinguished himself as a bright young man but not an outstanding student. He was a perfectionist, like his father, orderly and hard driving. But he was not very diligent when it came to classes that bored him, and his grades suffered. Eckert made a name for himself in other ways, as well. At one dance, he created the Osculometer—a machine he claimed measured the intensity, the passion, of a kiss. Couples would grab handles wired to the Osculometer, and an array of ten light bulbs progressively lit up when the pair kissed, completing the electric circuit. What the engineers knew—and their dates didn’t, was that if you got your lips wet enough, hands sweaty enough, and held the kiss long enough, you could get all ten bulbs to light up. Then a loudspeaker atop the device would proclaim: “WAH! WAH! WAHHHH!”.

In 1940, still only twenty-one years old, Pres applied for his first patent, which was granted two years later (USA patent number 2283545). It was called Light Modulating Methods and Apparatus and amounted to a motion-picture sound system. The machine was never sold, however.

Pres persisted at Moore School, earning his undergraduate degree in electrical engineering in 1941 and his master’s degree in 1943. He was widely regarded as a superb engineer while at Moore. However, he could be stubborn, and his work habits were considered odd. He was highly nervous and would rarely sit in a chair or stand still while thinking. Often he would crouch on top of a desk or pace back and forth.

John Mauchly and Pres first met in 1942, when the Army asked the University of Pennsylvania to have a class of scientists to help the war effort. Eckert was the teacher in this class and Mauchly was a student. Though they had different upbringings and were twelve years apart in age, John Mauchly and Pres Eckert became fast friends, wired together by a shared enthusiasm for creating devices. They had amazingly similar childhood interests. Both were fascinated by electricity and wiring, and both had rigged up the same kind of boyhood toys and gimmicks. Eckert was a man more interested in doing than teaching, and prescribed lab exercises bored him. Mauchly knew exactly what he wanted to work on, and saw little value in simple experiments of a caliber he might have assigned to his Ursinus students. Much of the lab time Eckert and Mauchly were assigned to spend together was actually spent talking about different ideas-including computing machines. The final result of these talks will be the creation of the first large electronic computer in the world—ENIAC.

After the WWII and creation of ENIAC, IBM had offered Eckert a job and his own lab for developing computers, but Mauchly talked him into jointly starting a new company—Electronic Control Company. Their first work, in 1946 and 1947, was with the National Bureau of Standards and the Census Bureau. They developed the specifications for a computer eventually known as the UNIVAC (Universal Automatic Computer) in 1948. Like most start-up companies developing complex hardware, Eckert and Mauchly ran into their share of financial problems, consistently underestimating the development costs for their computers. To raise money, they signed a contract in the fall of 1947 with the Northrop Aircraft Company to create a small computer for navigating airplanes—the BINAC (Binary Automatic Computer). The BINAC (completed in August 1949) and the UNIVAC were the first computers to employ magnetic tape drives for data storage. Smaller in size and comprised of fewer parts than the ENIAC, both machines had internal memories for storing programs and could be accessed by typewriter keyboards.

Eckert and Mauchly had been kept from bankruptcy by the support of Henry Straus, an executive for the American Totalisator Company, which manufactured the odds-making machines used at race tracks. When Straus was killed in a plane crash in October 1949, Eckert and Mauchly knew they had to sell UNIVAC. The Remington Rand Corporation acquired their company in February 1950. Eckert remained in research to develop the hardware for UNIVAC, while Mauchly devoted his time to developing software applications. In contrast to Mauchly, Pres succeeded in Sperry Rand, in 1959 he even became vice president and assistant to General Manager. The first UNIVAC, delivered to the Census Bureau in March 1951, proved its value in the 1952 presidential election between Dwight Eisenhower and Adlai Stevenson when it accurately predicted results less than an hour after the polls closed. Eckert and Mauchly’s patent on the ENIAC was challenged during an infringement suit between Sperry-Rand (formerly Remington), who now owned the rights to the computer and Honeywell.

On 28 October 1944, Eckert married Hester Caldwell. The couple had two sons, John Presper III and Christopher before Hester died in 1952. Ten years later, on 13 October 1962, Eckert married Judith A. Rewalt and he had two more children, Laura and Gregory.

Eckert received his honorary doctorate from the University of Pennsylvania in 1964. After his first patent in 1942, he also received 87 patents and numerous awards for his innovations, including the Howard N. Potts and John Scott Medals (both of which he shared with Mauchly). President Lyndon B. Johnson presented him with the National Medal of Science in 1969. Eckert was elected to the National Academy of Engineering in 1967. He remained with the Remington Rand Corporation through a number of mergers, retiring in 1989. He later served as a consultant to UNISYS and to the Eckert Scientific International Corporation, based in Tokyo, Japan.

John Presper Eckert died on 3 June 1995 in Bryn Mawr, Pennsylvania.