ENIAC – World’s first electronic computer?

ENIAC - World’s first electronic computer?

The ENIAC (Electronic Numerical Integrator and Computer) was a revolutionary machine for its time. It was one of the early computers to have been designed. It was state-of-the-art for that era. Dubbed “Giant Brain” by the press, it was the most advanced technology available to mankind at that time. ENIAC was also the harbinger of the computer era and spawned an entire industry, which will have a profound influence on the future of humans.

How did ENIAC come to be?

John Mauchly much like Atanasoff branched into computing when he had a serious computational problem when preparing an article for a scientific journal.

According to the article, in the site history-computer.com, he did dabble in some circuitry by himself but they were pretty basic.

“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 some 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 such 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.”

However, his ideas did not crystallise into anything concrete till his visit to Ames to meet Atanasoff. How he met Atanasoff and made his fateful journey to Ames is explained in the article on Atanasoff in the Iowa State University, Department of Computer Science website,

“In December 1940 Atanasoff attended the annual meeting of the American Association for the Advancement of Science (AAAS) in Philadelphia. John Mauchly was a scientist giving a presentation on his harmonic analyzer, a machine for carrying out calculations related to weather patterns. Following his presentation, JVA introduced himself to Mauchly and the two began a discussion about computing machines.

Mauchly expressed interest in the computer JVA was working on and had many questions about its operation. Atanasoff apologetically explained to Mauchly that he had been cautioned by Iowa State College and the patent lawyer Richard Trexler not to disclose information that may jeopardize the patent. But he did invite Mauchly to come to Ames and see the computer and how it functioned.

Mauchly accepted this invitation and traveled to Ames from Philadelphia, arriving on June 13, 1941. He spent four days in the company of either JVA or Clifford Berry. Mauchly saw the computer, and spent much time with JVA and Berry discussing how it was designed and how it worked. Mauchly also read parts of the 35-page documentation JVA and Berry had written on the machine and Mauchly took notes on its contents. When he asked Atanasoff for a copy, JVA declined, citing the need to protect the ideas and designs within until the patent application was finalized.

…… John Mauchly went on to build the ENIAC computer, and with J. Presper Eckert, patent the machine as the first digital electronic computer.”

World War II

With the advent of World War II, there was a dire need for a system of automatically calculating artillery firing tables for the United States Army’s Ballistic Research Laboratory. ENIAC was constructed for this purpose.

The article, The History of the ENIAC Computer in thoughtco.com, describes the effect World War II had on the design and development of the ENIAC computer.

“The American military sponsored their research because they needed a computer for calculating artillery-firing tables, the settings used for different weapons under varied conditions for target accuracy.

The Ballistics Research Laboratory, or BRL, the branch of the military responsible for calculating the tables, became interested after hearing about Mauchly’s research at the University of Pennsylvania’s Moore School of Electrical Engineering. Mauchly had previously created several calculating machines and had begun in 1942 designing a better calculating machine based on the work of John Atanasoff that would use vacuum tubes to speed up calculations.

On May 31, 1943, the military commission on the new computer began with Mauchly serving as the chief consultant and Eckert as the chief engineer. Eckert was a graduate student studying at the Moore School when he and Mauchly met in 1943.

It took the team about one year to design the ENIAC and 18 months and 500,000 tax dollars to build it. And by that time, the war was over. The ENIAC was still put to work though by the military, performing calculations for the design of a hydrogen bomb, weather prediction, cosmic-ray studies, thermal ignition, random-number studies and wind-tunnel design.”


Credit: US Army

ENIAC was a behemoth by today’s standards. According to Wikipedia, “By the end of its operation in 1956, ENIAC contained 17,468 vacuum tubes, 7200 crystal diodes, 1500 relays, 70,000 resistors, 10,000 capacitors and approximately 5,000,000 hand-soldered joints. It weighed more than 30 short tons (27 t), was roughly 2.4 m × 0.9 m × 30 m (8 × 3 × 100 feet) in size, occupied 167 m2 (1,800 ft2) and consumed 150 kW of electricity. This power requirement led to the rumour that whenever the computer was switched on, lights in Philadelphia dimmed.”

However, it was not a very reliable machine.

The Wikipedia article claims, “Several tubes burned out almost every day, leaving ENIAC nonfunctional about half the time. Special high-reliability tubes were not available until 1948. Most of these failures, however, occurred during the warm-up and cool-down periods, when the tube heaters and cathodes were under the most thermal stress. Engineers reduced ENIAC’s tube failures to the more acceptable rate of one tube every two days. According to a 1989 interview with Eckert, “We had a tube fail about every two days and we could locate the problem within 15 minutes.” In 1954, the longest continuous period of operation without a failure was 116 hours—close to five days.”

Programming the ENIAC

Programming the ENIAC involved an element of physical labour which we can scarcely fathom. It was very unlike what we have come to visualise as programming. That of a person sitting in front of the console typing away. This article in the Wikipedia explains how it could take days and perhaps weeks to run a program on it.

“ENIAC could be programmed to perform complex sequences of operations, including loops, branches, and subroutines. However, instead of the stored program computers that exist today, ENIAC was just a large collection of arithmetic machines, which had programs hard coded into the machines with function tables that each contained 1200 ten way switches. The task of taking a problem and mapping it onto the machine was complex, and usually took weeks. Due to the complexity of mapping programs onto the machine, programs were only changed after huge numbers of tests of the current program. After the program was figured out on paper, the process of getting the program into ENIAC by manipulating its switches and cables could take days. This was followed by a period of verification and debugging, aided by the ability to execute the program step by step.”

Role of women programmers in ENIAC

Considering the fact that programming the ENIAC involved physical work, it is surprising that the work was left to the women to do. The only reason seems to be that programming did not appear to be important to the men who worked on the ENIAC. All the action according to them was happening on the hardware side, so that they left the field wide open to the women to do the pioneering work on programming the ENIAC. A work for which the women would not be acknowledged for the better part of 5 decades.

According to this article in Columbia University website,

“Born on a farm in Missouri, the sixth of seven children, Jean Jennings Bartik always went in search of adventure. Bartik majored in mathematics at Northwest Missouri State Teachers College (now Northwest Missouri State University). During her college years, WWII broke out, and in 1945, at age 20, Bartik answered the government’s call for women math majors to join a project in Philadelphia calculating ballistics firing tables for the new guns developed for the war effort. A new employee of the Army’s Ballistics Research Labs, she joined over 80 women calculating ballistics trajectories (differential calculus equations) by hand – her title: “Computer.”

Later in 1945, the Army circulated a call for “computers” for a new job with a secret machine. Bartik jumped at the chance and was hired as one of the original six programmers of ENIAC, the first all-electronic, programmable computer. She joined Frances “Betty” Snyder Holberton, Kathleen McNulty Mauchly Antonelli, Marlyn Wescoff Meltzer, Ruth Lichterman Teitelbaum and Frances Bilas Spence in this unknown journey.

With ENIAC’s 40 panels still under construction, and its 18,000 vacuum tube technology uncertain, the engineers had no time for programming manuals or classes. Bartik and the other women taught themselves ENIAC’s operation from its logical and electrical block diagrams and then figured out how to program it. They created their own flow charts, programming sheets, wrote the program and placed it on the ENIAC using a challenging physical interface, which had hundreds of wires and 3,000 switches. It was an unforgettable, wonderful experience.

On February 15, 1946, the Army revealed the existence of ENIAC to the public. In a special ceremony, the Army introduced ENIAC and its hardware inventors Dr. John Mauchly and J. Presper Eckert. The presentation featured its trajectory ballistics program, operating at a speed thousands of time faster than any prior calculations. The ENIAC women’s program worked perfectly – and conveyed the immense calculating power of ENIAC and its ability to tackle the millennium problems that had previously taken a man 100 years to do. It calculated the trajectory of a shell that took 30 seconds to trace it. But, it took ENIAC only 20 seconds to calculate it – faster than a speeding bullet! Indeed!

The Army never introduced the ENIAC women.

No one gave them any credit or discussed their critical part in the event that day. Their faces, but not their names, became part of the beautiful press pictures of the ENIAC. For forty years, their roles and their pioneering work were forgotten and their story lost to history. The ENIAC Women’s story was discovered by Kathy Kleiman in 1985. Bartik will discuss what it means to be overlooked, despite unique and pioneering work, and what it means to be discovered again.”

Comparison with other early computers

According to the Wikipedia article,

“Mechanical and electrical computing machines have been around since the 19th century, but the 1930s and 1940s are considered the beginning of the modern computer era.

ENIAC was, like the Z3 and Harvard Mark I, able to run an arbitrary sequence of mathematical operations, but did not read them from a tape. Like the Colossus, it was programmed by plugboard and switches. ENIAC combined full, Turing complete programmability with electronic speed. The Atanasoff–Berry Computer (ABC), ENIAC, and Colossus all used thermionic valves (vacuum tubes). ENIAC’s registers performed decimal arithmetic, rather than binary arithmetic like the Z3, the ABC and Colossus.

Like the Colossus, ENIAC required rewiring to reprogram until September 1948. Three months earlier, in June 1948, the Manchester Small-Scale Experimental Machine (SSEM) ran its first program and earned the distinction of first stored-program computer. Though the idea of a stored-program computer with combined memory for program and data was conceived during the development of ENIAC, it was not initially implemented in ENIAC because World War II priorities required the machine to be completed quickly, and ENIAC’s 20 storage locations would be too small to hold data and programs.”

Limitations of ENIAC

ENIAC was eventually converted into a stored program computer, but the one that was unveiled was not a stored program computer. According to the Wikipedia article,

“ENIAC was a one-of-a-kind design and was never repeated. The freeze on design in 1943 meant that the computer design would lack some innovations that soon became well-developed, notably the ability to store a program.”

Conceptualisation of the EDVAC

EDVAC was the logical progression of the ENIAC, which was supposed to be a more advanced version of the machine. According to the Wikipedia article,

“Eckert and Mauchly started work on a new design, to be later called the EDVAC, which would be both simpler and more powerful. In particular, in 1944 Eckert wrote his description of a memory unit (the mercury delay line) which would hold both the data and the program. John von Neumann, who was consulting for the Moore School on the EDVAC, sat in on the Moore School meetings at which the stored program concept was elaborated. Von Neumann wrote up an incomplete set of notes (First Draft of a Report on the EDVAC) which were intended to be used as an internal memorandum—describing, elaborating, and couching in formal logical language the ideas developed in the meetings. ENIAC administrator and security officer Herman Goldstine distributed copies of this First Draft to a number of government and educational institutions, spurring widespread interest in the construction of a new generation of electronic computing machines.”

Controversy over the EDVAC report

This controversy strikes at the very root of the computer industry. If von Neumann was not the father of the stored program concept, then who was. To his credit, von Neumann meant the EDVAC report (that too an incomplete set of notes) to be an internal memorandum, which is why others were not credited in the report. According to Wikipedia article,

The First Draft of a Report on the EDVAC (commonly shortened to First Draft) was an incomplete 101-page document written by John von Neumann and distributed on June 30, 1945 by Herman Goldstine, security officer on the classified ENIAC project. It contains the first published description of the logical design of a computer using the stored-program concept, which has controversially come to be known as the von Neumann architecture.

The treatment of the preliminary report as a publication (in the legal sense) was the source of bitter acrimony between factions of the EDVAC design team for two reasons. First, publication amounted to a public disclosure that prevented the EDVAC from being patented; second, some on the EDVAC design team contended that the stored-program concept had evolved out of meetings at the University of Pennsylvania’s Moore School of Electrical Engineering predating von Neumann’s activity as a consultant there, and that much of the work represented in the First Draft was no more than a translation of the discussed concepts into the language of formal logic in which von Neumann was fluent. Hence, failure of von Neumann and Goldstine to list others as authors on the First Draft led credit to be attributed to von Neumann alone.

Patent issues

Mauchley and Eckert
Credit: topsecretrosies.com

Mauchly and Eckert would also face a lawsuit challenging their patent on the computer. According to the article,

“Mauchly and Eckert applied for a patent on the ENIAC in 1947 (but the USA patent 3120606 was granted as late as 4th of 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.”

According to Wikipedia,

“For a variety of reasons (including Mauchly’s June 1941 examination of the Atanasoff–Berry Computer, prototyped in 1939 by John Atanasoff and Clifford Berry for ENIAC, applied for in 1947 and granted in 1964, was voided by the 1973 decision of the landmark federal court case Honeywell v. Sperry Rand, putting the invention of the electronic digital computer in the public domain and providing legal recognition to Atanasoff as the inventor of the first electronic digital computer.”

50th year celebrations of the ENIAC

In 1996, in honour of the ENIAC’s 50th anniversary, The University of Pennsylvania sponsored a project named, “ENIAC-on-a-Chip”, where a very small silicon computer chip measuring 7.44 mm by 5.29 mm was built with the same functionality as ENIAC. Although this 20 MHz chip was many times faster than ENIAC, it had but a fraction of the speed of its contemporary microprocessors in the late 1990s.

ENIAC was by no means the first computer. It was not the first electronic computing device either. But, by showing that electronic computing circuitry could actually work, ENIAC paved the way for the modern computing industry that stands as its great legacy. Let’s look at the story of the great women who programmed the ENIAC next week.





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