The untold story of the 6 mathematicians who programmed the 1st supercomputer

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“New speed miracle, according to its inventors, calculates a math problem a thousand times faster than ever before.”

“One of the greatest secrets of the war – an amazing machine that applies electronic speeds for the first time to mathematical problems that until then were very difficult and complicated to solve – was announced this evening by the War Department,” reported the American newspaper New York Times on 14. September 1946.

The article was about ENIAC (Electronic Numerical Integrator And Computer or Computer and Electronic Numerical Integrator), the first programmable electronic digital general purpose computer. It would be a kind of fore-great-grandmother of the device you are reading this article on. The article details that it was “invented and perfected by two young men from the Moore School of Electrical Engineering: Drs. John William Maulchy, 38, a physicist and amateur meteorologist; and his partner J. Presper Eckert Jr., 26, a construction engineer.

The text also said that “many others at the school also helped.” The government approved the project in 1943 and “exactly 30 months later, [o computador] he worked, doing with ease what many trained men did at hard expense.’

What they fail to mention in the lengthy report is that those “many others” who “gave assistance” were not just “educated men” but six talented mathematicians who, by the way, did much more than just help with the project.

These omissions were not made only in the famous newspaper, nor only on that occasion.

The mathematician’s feat of programming the world’s first modern supercomputer — starting from scratch — went unnoticed.

“Women in Refrigerator Ads”

To be fair, journalists had no way of reporting something they didn’t even know.

The field of computers was in its infancy. What they saw was just a huge machine and no one understood the programming.

Also, no one told them about math.

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Who were these women?

Although they attended the first public presentation of the supercomputer on February 1, they were responsible for serving coffee during the event.

They were not even invited to the second presentation, two weeks later, attended by important figures from the scientific and technological community. Or at the grand fancy dinner with the director of the National Academy of Sciences of the United States.

The story was revealed decades later by computer scientist and historian Kathryn Kleiman, author of the book Evidence Ground.

She discovered the existence of the ENIAC programmers when she was a student at Harvard in the 1980s and found photos of the historic computer.

“The same women appeared repeatedly in the images, but their names were not in the captions,” Kleiman told HistoryExtra.

Determined to identify them, she consulted Gwen Bell, co-founder and later director of the Computer History Museum.

“They’re just women in refrigerator ads,” she replied, referring to the models who in the 1950s appeared in advertisements for home appliances.

But this explanation did not satisfy Kleiman.

He was able to make out the names of the women: Frances “Betty” Holberton, Kathleen “Kay” McNulty, Marlyn Wescoff, Ruth Lichterman, Frances “Fran” Bilas and Jean Jenningsz.

In this way, he saved his stories from ostracism.

A story that began on the battlefields.


Good snipers use their knowledge of weapons, weather and terrain to hit their targets.

With the development of artillery, this need for knowledge became more pressing.

In World War II, the big guns had a range of 14 to 23 km and whoever fired them couldn’t even see the target.

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Example of calculations made by “computers”

Armies had to take into account distance, humidity, air density, temperature and the weight of the projectile. In the desert, the difference in terrain required a new set of calculations.

These calculations showed very precisely at what angle to fire the weapon to hit the target.

In general, it was a task that took 30 to 40 hours—and you had to know how to solve calculus differential equations to do it.

But the soldiers on the battlefield did not have that much time. And many times they didn’t have the knowledge, so they used fire tables: lists with many variations.

To create these tables, the US military recruited over 100 qualified women, as most of the men were on the front lines.

The name of this kind of occupation was “computer”.

“The computer was a person before it was a machine,” Kleiman said.

But because they were not done by men, these jobs were considered “sub-professional” or “sub-scientific”.

Limited access

While the “computers” did the hard calculations, Maulchy, Eckert and a team of men were busy assembling the machine they had promised to deliver to the Army, to reduce the time it took to calculate a ballistic trajectory from a week to a few seconds.

Both groups—the female “computers” and the male machine builders—worked at the Moore School of Electrical Engineering at the University of Pennsylvania in Philadelphia.

“In fact, there was a large sign saying ‘No Entry’ on the door to the ENIAC room, and women were not allowed in.”

When the war was almost over, Maulchy and Eckert confirmed that the experimental material—eight feet tall, eighty feet wide, and weighing 30 tons—was ready.

“No one was sure it would actually work,” Kleiman said.

“But when they reviewed the contract, they realized that what they had to deliver to the Army was not ENIAC.”

“His mission was not to build a machine, but to build a machine that calculated the trajectory of ballistics,” the author clarified.

That’s when they picked the six best “computers” and told them:

“We made it, but you have to schedule it. And we’d like to see the schedule ready soon.”


Although they were highly trained mathematicians, they did not have a flight plan to complete the task.

“They gave us these big block diagrams. And we had to study them and figure out how to program them. We obviously had no idea what we were doing,” recalls one of the mathematicians.

They had to grope in the dark for the solution.

None of the hundreds of programming languages ​​we know today existed.

You couldn’t even “sit down in front of the ENIAC and write the instructions. It just didn’t exist,” Kleiman noted.

“That’s why I find what they’ve done so fascinating.”

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Drawing of the ENIAC modules included in the 1947 patent application

“First they had to learn how the 40 units of the integrator worked. One was a high-speed multiplier, one was a square root divider, and there were 20 units of something called an accumulator that could add, subtract, and cache a number.”

In essence, the ENIAC was an advanced series of calculators that were linked together to transmit information from one machine to another.

“So they had to break down a complicated equation to calculate ballistic trajectories in very, very incremental steps that ENIAC, or indeed any computer, could handle.”

“Then it was necessary to physically push the data and instructions, every microsecond of the program, to power the ENIAC.”

“The machine had thick wires for the numbers and rotated from one unit to the other and had other thin wires for what was called a program pulse: it wasn’t really an instruction, it was more of a pulse that started a function.

“If, for example, the high-speed multiplier was set to match two numbers, when it received this pulse it would multiply and send the result to another part of the ENIAC.”

his own light

The result of this enormous and brilliant effort by both ENIAC’s hardware and software inventors was an “incredible machine” that introduced several improvements, including the use of a binary system, which allowed calculations to be performed at speeds unimaginable until now. .

There were also downsides: reprogramming it was a nightmare, involving wiring everything up, which could take up to two days.

Still, what they all learned helped developers improve the next generation of computers.

One of the main achievements of ENIAC was to show the potential of what could be done.

Evidence Ground is not the first work in which Kleiman tells “this extraordinary story,” as well as that of other forgotten women in technology development.

In 2014, he produced a documentary called “The Computers” in which “ENIAC programmers look into the camera and say, ‘This is what we did'”.

Despite this, “some computer historians, particularly younger ones, have said, ‘No. The work they did was not important. They couldn’t have done it,” Kleiman said.

“I thought that once we pointed out that only half the history of computers had been written—more hardware than software, men but not women—historians would help complete the story. But it wasn’t.”

“Ultimately, I wrote the book with as much research, background and references as I could find, including what they were doing programming alongside their work on ENIAC, which is very complex.”

“I hope the book dispels the myth that women didn’t play a vital role in the early days of computing, breaks the stereotype that computers are for men, and inspires more girls to take an interest in this field.”

“We need to have the best people in high tech, computing, robotics and artificial intelligence.”

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Dozens of other women continued to program the ENIAC until 1955, including Gloria Gordon Bolotsky (left) and Ester Gerston

Maulchy and Eckert became famous and were credited with the creation and full operation of what the press called the “big brain”, the “electronic brain” and the “Einstein machine”.

The six ENIAC mathematicians were erased from this history, but continued to contribute to technological progress.

“If you’re first in a field, there’s no one who can say you don’t belong in it,” Kleiman said.

Each has left its mark on the cutting edge of computing.

Betty Holbertson, for example, created the first command code, invented the first sorting routine (the hardware that lets you sort things on the computer), and the first software package.

In 1959, he headed the Programming Research Branch at the Applied Mathematics Laboratory at the David Taylor Model Basin. collaborated with Grace Hopper on the COBOL programming language and invented the numeric keypad.


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