Women in Computing: The Invisible Pioneers

Abstract

This article traces the history of women in computing from the mathematical “computers” of the pre-electronic era through the ENIAC programmers of 1945, the systems pioneers of the 1960s and 1970s, and the documented reversal that began in 1984, when women’s participation in computer science began to fall even as it rose in every other technical field. It is the story of contributions that were systematically undercredited, erased from photographs, and omitted from histories, and of why recovering them matters not only for historical accuracy but for understanding how a profession shapes itself.

The Human Computers

Before electronic computers, “computer” was a job title. Mathematical tables (logarithms, trigonometric functions, ballistic trajectories) were calculated by rooms full of people performing arithmetic by hand, organized like assembly lines: one person computed, another checked, a third compiled the results. These rooms were filled largely with women, who were considered well-suited to precise, repetitive numerical work and could be paid less than men.

During World War II, the U.S. Army employed approximately two hundred women as computers at the University of Pennsylvania’s Moore School of Electrical Engineering, calculating artillery firing tables. When the Army funded the construction of the ENIAC (the first general-purpose electronic computer) in 1945, it selected six of these women to program it:

Jean Jennings Bartik, Frances Bilas Spence, Betty Holberton (Frances Elizabeth Snyder), Ruth Lichterman Teitelbaum, Kathleen McNulty Mauchly Antonelli, and Marlyn Wescoff Meltzer were assigned to translate ballistic calculation methods into machine programs for ENIAC. This was not clerical work. ENIAC had no programming language, no operating system, and no manual, its logical architecture was understood only through its circuit diagrams. The women studied the hardware schematics, mapped out the calculation flow, and physically configured the machine by setting 3,000 switches and plugging cables into patch panels.

Their work was neither easy nor recognized. When ENIAC was publicly demonstrated in February 1946, the women were not introduced to the press. The photographs that circulated showed the machine; the people who programmed it were not mentioned. At the celebratory dinner that evening, they were not seated at the main table. For decades, ENIAC was described primarily as a hardware achievement. The programmers were forgotten.

The Photograph That Erased Them

The most widely reproduced photograph of the ENIAC demonstration shows two women operating the machine. For decades, historians assumed they were “refrigerator ladies”, models placed for scale. They were Jean Jennings Bartik and Frances Bilas Spence, two of the six programmers. The error was not corrected in most accounts until Kathy Kleiman began researching the ENIAC programmers in 1985 and tracked down the surviving women. Her documentary The Computers (2014) and the subsequent book Proving Ground (2022) restored their names to the historical record, decades after the demonstration. (A separate 2010 PBS film, LeAnn Erickson’s Top Secret Rosies, told the broader story of the WWII women human computers.)

The Hidden Figures: NASA’s Human Computers

The same pattern (women performing mathematical computation that was essential to technical achievement, without credit or recognition) ran through the early American space program.

The National Advisory Committee for Aeronautics (NACA, predecessor to NASA) employed women mathematicians as “computers” from the 1930s onward. When NACA established a segregated computing pool in 1943, Dorothy Vaughan was hired as a mathematician. By 1949 she had become the section’s supervisor, the first Black supervisor at NACA and, later, NASA. Vaughan taught herself and her team FORTRAN when electronic computers arrived in the late 1950s, anticipating that digital machines would replace human computers and ensuring that her section retained its value through the transition. She was one of NASA’s first programmers at scale.

Katherine Johnson joined NACA in 1953. Her specialty was orbital mechanics, the mathematics of trajectories under gravity. When NASA began the Mercury program, she calculated the trajectory for Alan Shepard’s Freedom 7 mission (1961), the first American crewed spaceflight. For John Glenn’s 1962 orbital mission, the first use of electronic IBM computers for trajectory calculation, Glenn himself requested that Johnson verify the computer’s output by hand before he would agree to fly. “If she says they’re good,” Glenn reportedly said, “then I’m ready to go.” She verified them. He flew.

Mary Jackson worked alongside Vaughan and Johnson at NASA’s Langley Research Center. After lobbying the city of Hampton, Virginia, to allow a Black woman to take graduate-level engineering courses at a segregated institution, she completed the coursework and became NASA’s first Black female engineer in 1958. She spent much of her later career as a Human Resources administrator, working to help other women and minorities advance into technical roles.

Their contributions were unknown to the public until Margot Lee Shetterly’s book Hidden Figures (2016) and the subsequent film brought them to wide attention, fifty years after the events described.

The Pioneers of the Computer Age

The ENIAC programmers and the NASA computers were not anomalies. The first generation of electronic computing drew heavily on women who came from mathematics, and the work of programming (considered lower-status than hardware engineering) was initially open to them in ways that other technical roles were not.

Betty Holberton wrote the Sort-Merge Generator for UNIVAC, a program that emitted sorting programs from a specification. Grace Hopper’s summary: “She wrote the first program that wrote a program.” Holberton also wrote the first statistical analysis package, used for the 1950 US Census, invented the debugging breakpoint, and worked on the early COBOL and FORTRAN standards, later steering the FORTRAN 77 and Fortran 90 revisions from the National Bureau of Standards. Jean Bartik led the team that converted ENIAC to a stored-program computer in 1948. Their contributions belong in the same sentence as the hardware engineers who built the machines they programmed.

Kathleen Booth created the first assembly language at Birkbeck College, London, in 1947 (the first systematic notation that let programmers write mnemonics instead of raw binary) and later did early work on machine translation and neural network simulation. On the other side of the Iron Curtain, Kateryna Yushchenko developed the Address programming language in Kyiv in 1955, introducing indirect addressing (the concept behind the modern pointer) years before it reached Western languages. And before the computer age proper, Elizebeth Smith Friedman founded much of American cryptanalysis, only to see the FBI claim her wartime results, a paradigm case of the credit-erasure this article documents.

Mary Allen Wilkes was hired by MIT’s Lincoln Laboratory in 1959 after graduating from Wellesley with a degree in philosophy. Told there were no programming jobs for women, she applied to universities instead, and MIT hired her. She became one of the primary programmers of the LINC (Laboratory Instrument Computer), one of the first laboratory computers small enough to be used outside a data center. In 1965, when MIT’s LINC project ended, Wilkes took her machine home to Baltimore, making her, arguably, the first person to use a computer in a private home.

Frances Allen joined IBM Research in 1957 with a master’s degree in mathematics, intending to stay two years to pay off student loans. She stayed forty-five. Her work on compiler optimization (particularly on program flow analysis, parallelism detection, and automatic vectorization) defined the field for decades. She became IBM’s first female Fellow in 1989 and in 2006 received the Turing Award, the first woman to do so, forty years after the prize was established.

Lynn Conway made foundational contributions to VLSI chip design methodology at Xerox PARC in the 1970s while concealing her identity as a transgender woman following her termination from IBM in 1968. Her work with Carver Mead on the Mead-Conway VLSI design rules democratized chip design, enabling universities and startups to design custom silicon for the first time. The story of how her contributions were simultaneously foundational and invisible is among the more complex in computing history.

Evelyn Berezin designed one of the first computerized airline reservation systems (the United Airlines Reservisor, around 1962) and then, having been offered and then refused a New York Stock Exchange job in 1960 once they learned she was a woman, founded her own company. Redactron’s Data Secretary (1971) was the first standalone word processor, and Berezin ran the firm as president until she sold it to Burroughs in 1976, one of the very few women heading a computer company in that era. Her name faded so completely that a 2010s essay about her was titled “Why is this woman not famous?”

In Britain, Stephanie “Steve” Shirley drew the same conclusion from the same ceiling. Passed over for promotion at the Post Office Research Station, she founded Freelance Programmers in 1962 with £6 of capital and staffed it almost entirely with women programming from home, women the industry had discarded at marriage or motherhood. She signed her sales letters “Steve” because letters signed Stephanie got no answer. The company programmed Concorde’s black box and, as Xansa, reached a valuation near $3 billion.

The 1984 Reversal

Through the 1960s and 1970s, women’s share of computer science graduates rose steadily, from about 13.6% in 1970 to a peak of 37.1% of CS bachelor’s degrees in the United States in 1984. Then something changed.

That year, the percentage began to fall. By 2010 it had dropped to roughly 18%, about half the 1984 peak. In medicine, law, and physical sciences, women’s participation continued to rise. In computer science alone, it reversed.

The 1984 Reversal: What Changed

Researchers including Jane Margolis and Allan Fisher (Unlocking the Clubhouse, 2002) documented a confluence of factors:

The personal computer entered the home, marketed almost exclusively to boys and men. Families purchased computers for sons; boys arrived at college with years of experience; girls did not. Professors began assuming prior experience and designing courses accordingly.
The “nerd” cultural identity (depicted in films, advertising, and media) was male. Computing culture signaled that this was a male space.
Self-selection effects reinforced each other: fewer women enrolled, fewer women became professors, fewer women appeared as role models, fewer women enrolled.

The reversal was not biological or inevitable. In India and several other countries, women continued to enter computer science at rates comparable to other technical fields. The 1984 reversal was a cultural and structural artifact, which means it was, in principle, reversible.

Legacy: Recovery and Ongoing Gaps

The recovery of women’s historical contributions to computing has been gradual and incomplete. The ENIAC programmers were inducted into the Women in Technology International Hall of Fame in 1997. Frances Allen’s Turing Award in 2006 drew attention to the decades of unrecognized work preceding it. Lynn Conway’s contributions were recognized by the Computer History Museum in 2014.

The representation gap persists. As of the early 2020s, women hold approximately 26% of computing jobs in the United States, below their share in the 1980s. Leadership positions lag further. The gap is larger in some subfields (systems, security) than others (data science, UX).

The historical record matters for a practical reason: the norms and culture of computing were established in the decades when women’s participation was being excluded or minimized. Understanding that these norms were constructed (not natural) is a prerequisite for examining which of them serve the field and which merely perpetuate the conditions of their origin.

For Ada Lovelace, the earliest figure in this lineage, see Ada Lovelace and the Analytical Engine. For Grace Hopper, see Grace Hopper: The Queen of Code. For Margaret Hamilton, see Margaret Hamilton and the Apollo Software.