Hitting the Books: The women who made ENIAC more than a weapon

AAfter Mary Sears and her team revolutionized the field of oceanography, but before Katherine G. Johnson, Dorothy Vaughan, and Mary Jackson helped launch John Glenn into orbit, a cadre of women programmers working for the US government, faced with an impossible task: train ENIAC, the world’s first modern computer that can do more than quickly calculate artillery trajectories. Though successful – and without the aid of a guide or manual – their names and deeds went down in the annals of history until author Kathy Kleiman, through a Herculean research effort, brought their stories to light Proving Grounds: The untold story of the six women who programmed the world’s first modern computer.

excerpt from the book Proving Grounds: The untold story of the six women who programmed the world’s first modern computer by Kathy Kleimann. Copyright © 2022 First Byte Productions, LLC. Reprinted with permission from Grand Central Publishing. All rights reserved.

Demonstration day, February 15, 1946

The Moore School was ready when people arrived by train and tram. John and Pres and the university’s engineers, deans, and professors wore their best suits, and the army officers wore dress uniforms with shiny medals. The six women wore their best professional costumes and gowns.

Kay and Fran occupied the front door of Moore School. When the scientists and technologists arrived, some even from Boston, they were warmly welcomed by the two women. They asked everyone to hang their heavy winter coats on the portable coat racks that Moore School staff had placed nearby. Then they led her down the hall and around the corner to the ENIAC room.

Just before 11:00 a.m., Fran and Kay ran back into the ENIAC room as the demonstration began.

When they slid to the back of the room, everything was ready. At the front of the large ENIAC U there was room for a few speakers, a few rows of chairs and plenty of standing room for invited guests and ENIAC team members. Across the room, Marlyn, Betty, and Jean stood in the background, and the women smiled at each other. Your moment of glory was about to begin. Ruth stayed outside, pointing latecomers in the right direction.

The room was packed and filled with anticipation and wonder as people saw ENIAC for the first time.

The demonstration day started with some introductions. Major General Barnes began with the BRL officers and the Deans of the Moore School, and then introduced John and Pres as co-inventors. Then Arthur came forward and introduced himself as Master of Ceremonies for the ENIAC events. He ran five programs, all with the remote control he was holding.

The first program was a supplement. Arthur pressed one of the buttons and the ENIAC sprang to life. Then he performed a multiplication. His knowledgeable audience knew that ENIAC calculated many times faster than any other machine in the world. Then he did the table with squares and cubes and then with sine and cosine. So far Demonstration Day has been the same as two weeks ago and for this demanding audience the presentation has been quite boring.

But Arthur was just getting started and the drama was about to begin. He told them that he would now complete a ballistic trajectory on ENIAC three times.

He pressed the button and let it run once. The trajectory “went beautifully,” Betty recalled. Then Arthur ran it again, a version of the trajectory without the punch card printing, and it ran much faster. Punch cards actually slowed things down a bit.

Arthur then pointed everyone to the grids of tiny lights atop the accumulators, urging his participants to examine them closely in the moments to come. He nodded to Pres, who was standing against the wall, and suddenly Pres turned off the light. Only a few small status lights on ENIAC’s units were lit in the black room. Everything else was in the dark.

With a click of the button, Arthur brought the ENIAC to life. The ENIAC lit up for twenty seconds. Those who watched the accumulators closely saw the 100 tiny lights twinkle as they moved at lightning speed, first ascending as the rocket ascended toward the sky, and then descending as it raced back to earth, the lights constantly changing and blinking . Those twenty seconds felt like an eternity and instant at the same time.

Then the ENIAC ended and darkness filled the room again. Arthur and Pres waited a moment, then Pres turned on the light and Arthur dramatically announced that ENIAC had just completed a trajectory faster than it would take for a missile to exit the artillery muzzle and hit its target. “Everyone gasped.”

Less than twenty seconds. This audience of scientists, technologists, engineers and mathematicians knew how many hours it took to calculate a differential equation by hand. They knew that ENIAC calculated a week’s work in less than two dozen seconds. They knew the world had changed.

Climax accomplished, everyone in the room beamed. Army officers knew their risk had paid off. ENIAC engineers knew their hardware was a success. The deans of the Moore School knew they no longer had to worry about embarrassment. And the ENIAC programmers knew their trajectory had worked perfectly. Years of work, effort, ingenuity and creativity had come together in twenty seconds of pure innovation.

Some would later refer to this moment as the birth of the “Electronic Computing Revolution”. Others would soon call it the birth of the information age. After those precious twenty seconds, no one would take a second look at the magnificent Mark I electromechanical computer or differential analyzer. After Demonstration Day, the country was on a clear path toward programmable, all-electronic, general-purpose computers. There was no other direction. There was no other future. John, Pres, Herman and some of the engineers answered questions from the guests and then the formal session ended. But nobody wanted to go. The participants surrounded John and Pres, Arthur and Harold.

The women circulated. They had taken turns running punch cards through the tab and sharing stacks of trajectory printouts. They divided the papers and walked around the room to distribute them. Participants enjoyed a trajectory, a memento of the big moment they just witnessed.

But no participant congratulated the women. Because no guest knew what they had done. Amid the announcements and introductions from Army officers, Moore School deans and ENIAC inventors, the programmers had been left out. “None of us girls were ever introduced as a part of it,” Kay later remarked.

Since no one thought to name the six young women who programmed the ballistic trajectory, the audience was unaware of their work: they spent thousands of hours learning ENIAC’s units, studying their “direct programming” method , breaking down the ballistic trajectory into discrete steps, writing the detailed pedal sheets for the trajectory program, setting up your program on ENIAC, and learning ENIAC “down to a vacuum tube”. Later, Jean said they received “a lot of compliments” from the ENIAC team, but at that moment they were unfamiliar to the guests in the room.

And at that moment it didn’t matter. They cared about the success of ENIAC and their team and they knew they had played a vital role in the day’s success. This was a day that would go down in history and they had been there and played an invaluable role.