75 years ago, the world's first modern computer made its public debut

75 years ago, the world's firs...
ENIAC was built to compute gunnery tables
ENIAC was built to compute gunnery tables
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US Army recruiting advertisement featuring ENIAC
US Army recruiting advertisement featuring ENIAC
ENIAC had to be physically rewired to be programmed
ENIAC had to be physically rewired to be programmed
ENIAC was built to compute gunnery tables
ENIAC was built to compute gunnery tables
A section of ENIAC with two of its programmers
A section of ENIAC with two of its programmers
ENIAC weighed 27 tonnes
ENIAC weighed 27 tonnes
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Seventy five years ago, the world was introduced to ENIAC, the first ever electronic, programmable, general purpose, digital computer, in a demonstration that not only ushered in the first glimmers of the computer age, but also shaped popular conceptions of the computer that continue to this day.

ENIAC is short for Electronic Numerical Integrator and Computer, and though it was closer in its basic design to modern computers, it wasn't the first electronic computer. However, its rivals were all either experiments that ended up in dusty obscurity or ultra top secret projects whose existence wasn't made public until the 1970s.

Nevertheless, when ENIAC made its debut before the newsreel cameras in February 1946, it definitely looked the part for what would become the stereotypical giant electronic brain. It cost US$500,000 (about US$7.2 million in 2020 dollars), weighed in at 27 tonnes, stretched in a square U-shape for 80 feet (24 m), covered 1,800 square feet (167 sq m), and gulped down 150 kW of electricity to power its 18,800 radio valves or vacuum tubes.

ENIAC had to be physically rewired to be programmed
ENIAC had to be physically rewired to be programmed

By today's standards, it would underperform a bargain store pocket calculator, but when it was built, it represented a leap forward in calculating speed of several orders of magnitude.

It started life in 1942 at the Moore School of Electrical Engineering of the University of Pennsylvania with backing by the US Army Ordnance Department and the Ballistic Research Laboratories as part of a project to produce gunnery tables for new artillery being developed for the US effort after joining the Second World War.

At the time, this job was given to computors. No, that is not a typo. Before the Second World War, computors were people, and during the war, due to it being a low-status job and the desire to free up men for combat duty, it was usually done by women. In this case, hundreds of them.

A section of ENIAC with two of its programmers
A section of ENIAC with two of its programmers

Enter physicist Dr. John W. Mauchly, who was already entertaining the idea of building an electronic computer to analyze the weather that could handle these calculations automatically at high speed. In June 1942 an agreement was signed with the US Army for "Project PX" to build what would become ENIAC at the Moore School, with Mauchy and young electronics engineer J. Presper Eckert, Jr. in charge of the design.

What was built over the next three years was a monster of a machine. It consisted of 42 panels that were 9 ft (2.7 m) high and 1.1 ft (33 cm) thick made out of black-painted sheet steel with ducts at the top to allow air to circulate and cool the tubes and a large extractor fan system in the ceiling. In addition, the computer had its own dedicated power line.

Inside were over 18,800 vacuum tubes – an unheard of number at that time. Worse, they were intended to act in a digital system where they were either on or off instead of as analog devices as they were designed. Engineers believed that having so many tubes would result in a failure rate so high that the machine might not be able to complete a single computation before breaking down.

ENIAC weighed 27 tonnes
ENIAC weighed 27 tonnes

As it was, the failure rate in the beginning was twice a day. As more reliable tubes became available, this dropped to once every two days. For this reason, the construction was modular, so a unit could be pulled and replaced rather than the faulty part being tracked down.

If the number of tubes wasn't impressive enough, there were also 70,000 resistors, 10,000 capacitors, 1,500 relays, 6,000 manual switches, and five million soldered joints.

ENIAC had no way to store programs, so it had to literally be rewired for every new task. This was done by a crew of female operators who would pull and re-plug cables and set switches for each new set of calculations.

In fact, led by Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman, they were the world's first computer programmers – a job for which there wasn't even a name. Without even a manual, they had to learn schematics and work with block diagrams to write the programs and instructions on how to reconfigure the machine on paper. As it was, it took days to program ENIAC and weeks to debug.

US Army recruiting advertisement featuring ENIAC
US Army recruiting advertisement featuring ENIAC

ENIAC never did any actual war work. It wasn't even run until three months after the surrender of Japan, but it was already doing work on the first hydrogen bomb when the Las Alamos National Laboratory learned of its existence.

Then, on February 15, 1946, ENIAC was unveiled to the press. As part of this, the Pathé newsreel cameras were invited to film the tubes flashing as the computer solved a missile trajectory in 20 seconds – 10 seconds before the shell would have landed.

Unfortunately, the cameras couldn't see the lights, so neon bulbs were installed on the tubes and then covered with ping pong balls cut in half with numerals painted on them. As ENIAC worked, the results flew across the panels in a display so dramatic that for decades the public associated computers with control panels covered with flashing lights.

It also introduced the idea of the computer as a mysterious, all-powerful giant electronic brain that would be smarter than humans by teatime next Wednesday when ENIAC was basically a spreadsheet app. In other words, ENIAC didn't just introduce the computer age, but the myth of HAL 9000 and Skynet.

Oddly, ENIAC's creators didn't share the public's opinion. By the time they'd frozen the design, Mauchly and Eckert had come up with a much more advanced computer called EDVAC. While ENIAC was improved and continued to work until it was shut down in 1955, Mauchly and Eckert started the first commercial electronic computer company, the Eckert–Mauchly Computer Corporation (EMCC), which would go on to build the famous Univac computer that processed the US census data in 1950 and predicted the winner of the 1952 US presidential election.

Today, ENIAC has long been broken up, but its surviving panels are on display at the University of Pennsylvania, the Smithsonian, the Science Museum in London, and other locations.

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Good article, just one issue: ENIAC was not the first "modern" computer. The first modern computer came from Iowa State University in 1938. Read more here:
I think that was very interesting. It is amazing how far computers have come; from taking up a whole room to fitting into the palm of ones hand.
ENIAC was not the first computer of the modern age, it was the second. The first was Colussus which was developed by a British team at Bletchley Park to decode German encrypted messages. Von Neuman and an American team were allowed access to this highly secret machine following America's entry into the war in late 1941. 'Von Neuman's Bottleneck' which even today is still an issue in computing, was actually 'Turing's Bottleneck' but due to the UK's official secrets act, the story of the UK's computer was kept secret until 1974, by which point IBM ruled the world.
Or even the UK's Colossus in 1943 -
Konrad Zuse
Konrad Zuse (German: 22 June 1910 – 18 December 1995) was a German civil engineer, pioneering computer scientist, inventor and businessman. His greatest achievement was the world's first programmable computer; the functional program-controlled Turing-complete Z3 became operational in May 1941.
Born: 22 June 1910, Berlin, Prussia, German Empire
Died: 18 December 1995 (aged 85), Hünfeld, Hesse, Germany
Known for: Z3, Z4, Plankalkül, Calculating Space (cf. digital physics)
Nationality: German
Konrad Zuse - Wikipedia
I believe it was the first atomic bomb at Los Alamos not the first hydrogen bomb which came later in the 50s/.
There is some competition for the title of World's first truly programmable computer, some would consider the first really effective computer was General Post Office engineer Tommy Flowers' "Colossus" at Bletchley Park Government Code and Cypher School that did hugely valuable service decrypting the Enigma code messages and was thus instrumental in winning the WWII Battle of the Atlantic.
As to programmers, the first has to have been Ada, Lady Lovelace (1815-1852), who wrote code for Charles Babbage's unfortunately never completed "Analytical Engine", who is commemorated by having a programming language - ADA - named after her.
Incidentally, Babbage's first calculating machine - the Difference Engine built in the 1820s - was built for exactly the same purpose as ENIAC, the production of range tables for artillery pieces.
Lindsey Roke
I wonder why the Americans claim this was the world's first electronic computer when Colossus at Bletchley Park (north of London) had already been deciphering German codes for a couple of years (Google it for more details)
Phil Runciman
The first programmer was Ada Lovelace. The wording in the heading was careful but may not be correct. The Moore School was influential but Tommy Flower's team may have beaten them to it! Colossus was kept secret for so many years that your story has gained credence. "The prototype, Colossus Mark 1, was shown to be working in December 1943 and was in use at Bletchley Park by early 1944"
Nice article David.

It was unclear how the ENIAC worked on the hydrogen bomb theory after Japan’s surrender. The liquid deuterium mass & yield equations for the initial H-bomb development would have required ENIAC's massive computational power. Deuterium (and Tritium) are isotopes of Hydrogen with Neutron(s) that will undergo fusion at lower temperatures (thermo-) if the nuclear reaction could be triggered by a 'fission trigger' - the super event was entirely theoretical - if at all possible - as reported by Teller & Fermi conversations in late 1941.

The Manhattan project took 1920’s theoretical physics to reality. The “Little Boy” Hiroshima bomb was Uranium-235. Fat Man Kokura bomb was a plutonium-239 solid core bomb dropped instead on Nagasaki due to visibility issues. The top-secret Trinity test was the first fission reaction of P-239.

It would have been nice to have listed the 5 or 6 programmable computers used prior to ENIAC – the mechanical/electric computers like Enigma, mechanical like an abacus, etc.
But great info!
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