This dynamic was at work in the development of the first programmable digital computer in the United States, the Electronic Numerical Integrator and Computer, or Eniac, during the 1940s. Funded by the military, the thing was a behemoth, weighing more than 30 tons and including 17,468 vacuum tubes. Merely getting it to work was seen as the heroic, manly engineering feat. In contrast, programming it seemed menial, even secretarial. Women had long been employed in the scut work of doing calculations. In the years leading up to the Eniac, many companies bought huge electronic tabulating machines — quite useful for tallying up payroll, say — from companies like IBM; women frequently worked as the punch-card operators for these overgrown calculators. When the time came to hire technicians to write instructions for the Eniac, it made sense, to the men in charge, to pick an all-female team: Kathleen McNulty, Jean Jennings, Betty Snyder, Marlyn Wescoff, Frances Bilas and Ruth Lichterman. The men would figure out what they wanted Eniac to do; the women “programmed” it to execute the instructions.
“We could diagnose troubles almost down to the individual vacuum tube,” Jennings later told an interviewer for the IEEE Annals of the History of Computing. Jennings, who grew up as the tomboy daughter of low-income parents near a Missouri community of 104 people, studied math at college. “Since we knew both the application and the machine, we learned to diagnose troubles as well as, if not better than, the engineer.”
The Eniac women were among the first coders to discover that software never works right the first time — and that a programmer’s main work, really, is to find and fix the bugs. Their innovations included some of software’s core concepts. Betty Snyder realized that if you wanted to debug a program that wasn’t running correctly, it would help to have a “break point,” a moment when you could stop a program midway through its run. To this day, break points are a key part of the debugging process.
In 1946, Eniac’s creators wanted to show off the computer to a group of leaders in science, technology and the military. They asked Jennings and Snyder to write a program that calculated missile trajectories. After weeks of intense effort, they and their team had a working program, except for one glitch: It was supposed to stop when the missile landed, but for some reason it kept running. The night before the demo, Snyder suddenly intuited the problem. She went to work early the next day, flipped a single switch inside the Eniac and eliminated the bug. “Betty could do more logical reasoning while she was asleep than most people can do awake,” Jennings later said. Nonetheless, the women got little credit for their work. At that first official demonstration to show off Eniac, the male project managers didn’t mention, much less introduce, the women.
After the war, as coding jobs spread from the military into the private sector, women remained in the coding vanguard, doing some of the highest-profile work. The pioneering programmer Grace Hopper is frequently credited with creating the first “compiler,” a program that lets users create programming languages that more closely resemble regular written words: A coder could thus write the English-like code, and the compiler would do the hard work of turning it into ones and zeros for the computer. Hopper also developed the “Flowmatic” language for nontechnical businesspeople. Later, she advised the team that created the Cobol language, which became widely used by corporations. Another programmer from the team, Jean E. Sammet, continued to be influential in the language’s development for decades. Fran Allen was so expert in optimizing Fortran, a popular language for performing scientific calculations, that she became the first female IBM fellow.
When the number of coding jobs exploded in the ’50s and ’60s as companies began relying on software to process payrolls and crunch data, men had no special advantage in being hired. As Wilkes had discovered, employers simply looked for candidates who were logical, good at math and meticulous. And in this respect, gender stereotypes worked in women’s favor: Some executives argued that women’s traditional expertise at painstaking activities like knitting and weaving manifested precisely this mind-set. (The 1968 book “Your Career in Computers” stated that people who like “cooking from a cookbook” make good programmers.)
The field rewarded aptitude: Applicants were often given a test (typically one involving pattern recognition), hired if they passed it and trained on the job, a process that made the field especially receptive to neophytes. “Know Nothing About Computers? Then We’ll Teach You (and Pay You While Doing So),” one British ad promised in 1965. In a 1957 recruiting pitch in the United States, IBM’s brochure titled “My Fair Ladies” specifically encouraged women to apply for coding jobs.