Dark Secrets

The Secret Female Computers of WWII

During World War II an unassuming fraternity house at the University of Pennsylvania was converted into an office building. On the door hung a sign reading: “WOMEN ONLY.” What went on behind that door would remain forgotten for nearly 50 years.

The ENIAC took up an entire room.

Glen Beck and Betty Snyder program the ENIAC at the Ballistic Research Laboratory. Source.

During the war, the U.S. Army Ordnance struggled with the demands for ballistics testing and research. So the Army established a secret unit to catch up. They called it the Philadelphia Computing Section (PCS) and based it at the Moore School of Electrical Engineering at the University of Pennsylvania.

More than 100 young female college graduates skilled in mathematics were hired for the team. They worked night and day, in three shifts, to complete ballistics tables.

Out of these 100 women, a group of six was chosen. They were to become a top-secret team carrying out ballistics calculations for the U.S. Army. All were upgraded in their security clearance and became the first to program algorithms into the first all-electronic digital computer, ENIAC (Electronic Numerical Integrator and Computer). 

Women work with the ENIAC computer which took up a whole room

Kay McNulty, Alyse Snyder and Sis Stump operate the differential analyzer in the basement of the Moore School. Source.

The ENIAC, and the men who invented it, became famous. The woman who programmed the machine were not celebrated until relatively recently. Even when their involvement was revealed in a newsreel soon after the war, they often went uncredited and even unnamed. When researcher Kathy Kleiman rediscovered photos of the ENIAC and the women who programmed it, she was told the women were just models.

After the successful reveal and demonstration of the working ENIAC, which the women had perfected alone, they were left off the guest list to celebrate the new machine. “Betty and I were ignored and forgotten following the demonstration. We felt as if we had been playing parts in a fascinating movie that suddenly took a bad turn, in which we had worked like dogs for two weeks to produce something really spectacular and then were written out of the script,” Betty Jean Jennings said.

Two women operating the ENIAC's main control panel.

Betty Jennings and Frances Bilas (right) set up a part of the ENIAC’s main control panel. Source.

Many of the ballistics manuals developed by the women were used by bombardiers on B-17’s flying from England to hit targets in Germany. Though at the time, the women were not told what their assignments were being used for.

During the war the women were tightly knit, mainly keeping to themselves while working long hours. They were all single and surrounded by single soldiers. The women later remembered multiple romances begun over Tom Collins cocktails in the booths of the officers’ club.

On the day Germany’s surrender was broadcast over the radio, the women briefly paused work to celebrate with the crowds dancing around the college. Then they returned to their office.

New tasks awaited like calculations for mustard gas weapons in case Japan invaded.

Two women wiring the right side of the ENIAC with a new program.

Marlyn Wescoff (standing) and Ruth Lichterman wire the right side of the ENIAC with a new program. Source.

World War II ended before ENIAC had solved any new ballistics equations. The first “real” problem solved on the machine, after testing and debugging by the women, was a classified calculation related to the nuclear trigger for the hydrogen bomb.

Jennings, left, Wescoff, center and Lichterman, work on portable function tables programming trigonometric functions into the room size computer.

Jennings (left), Wescoff (center), and Lichterman work on portable function tables programming trigonometric functions into the room size computer. Source.

Some of the “Female Computers”:

  • Betty Jean Jennings Bartik was born into a farming family in Gentry County, Missouri in 1924. Her parents instilled in her a value for education so when she came of age, instead of aspiring to marry, she borrowed $400 and headed off to college.

    At Northwest Missouri State Teachers College she was the only woman majoring in mathematics. Her calculus teacher received a recruitment letter from Aberdeen Proving Ground. Girl math majors were wanted for a job at the University of Pennsylvania as human computers (“computer” was a career at the time not an electronic machine). The ad read: “Wanted: Women With Degrees in Mathematics…Women are being offered scientific and engineering jobs where formerly men were preferred. Now is the time to consider your job in science and engineering…You will find that the slogan there as elsewhere is WOMEN WANTED!”

    Betty Jean applied for the job and moved back home. Eventually she received a telegram reading: “REPORT IMMEDIATELY.” She was on the train the next day at midnight. During the war Betty Jean married engineer, William Bartik, who worked down the hall, earned a master’s degree in English and dropped her first name becoming Jean Bartik. She left her job in 1951 and had three children. She returned to computing in 1967 and worked as a programmer, trainer and editor at major computer firms.

  • Betty Snyder Holberton who had been asked by her math professor if she’d be better off at home with children on her first day of classes, also worked and led the ENIAC team with Jennings. She worked in the computing and programming field for the rest of her life. Betty is also credited as inventing the first sort routine and helping to design the first commercial computers.
  • Marlyn Wescoff Meltzer was one of the original six programmers. She left the team at the end of the war and spent her life volunteering for charities and raising a family.
The machine that prints and tabulates the answers to the problems solved by the ENIAC.

The machine that prints and tabulates the answers to the problems solved by the ENIAC, 1946. Source.

  • Kathleen (Kay) McNulty Mauchly Antonelli, originally from Ireland, was also one of the ENIAC programmers. John Mauchly, ENIAC co-inventor, wanted to hire Kay for his new computer company after the war but when his wife died in a drowning accident in 1946 he ended up proposing to Kay. They married in 1948 and had five children. She worked on software design for later computers designed by her husband.
  • Doris Blumberg Polsky and Shirley Blumberg Melvin were twin sisters who worked as computers. Doris married a law professor after the war ended and opened Twin Realty were her husband’s backing. The company only hired women to combat sexism, established a daycare for the use of women who wanted to work and helped integrate their Philadelphia neighborhood, Mt Airy, by stopping white flight as new black neighbors moved in.
  • Frances Bilas Spence majored in mathematics with a minor in physics while in college. At school she met Kay McNulty who she would go to work with as one of the first ENIAC programmers. After the war she married Homer Spence an Army electrical engineer from the Aberdeen Proving Grounds. She worked on the ENIAC for several years after the war before resigning to have children.
  • Ruth Lichterman Teitelbaum was one of the first ENIAC programmers. She travelled with the ENIAC after the war to the Aberdeen Proving Ground to train the next group of ENIAC programmers.
One of the control boards used to program ENIAC.

One of the control boards used to program ENIAC. Source.

You can read a lot more about the women and see more photos in this paper by W. Barkley Fritz here. There are also two recent documentaries but they aren’t readily available for free. You can see more about them here: Top Secret Rosies and The Computers.

Sources: 1, 2, 3, 4, 5, 6, 7, 8, 9