Thread by @enn_nafnlaus

I was today years old when I learned that all six of the programmers behind ENIAC, the first digital computer, were women (whose work went almost entirely unrecognized until the 1980s).

en.wikipedia.org/wiki/ENIAC

Their first program was nuclear simulations for a hydrogen bomb.

The six - Jean Jennings, Marlyn Wescoff, Ruth Lichterman, Betty Snyder, Frances Bilas, and Kay McNulty - were "human computers" who got their positions due to wartime labour shortages. They kept their jobs after the war because their experience was too difficult to replace.

As generative programming languages did not yet exist, "programming" ENIAC meant switches and rewiring cables, which required a full understanding of its blueprints. Photos of them next to ENIAC referred to them as "refrigerator ladies" & they had to serve as hostesses for guests

Kay McNulty's family fled to the US when she was a child, as her father had been imprisoned for IRS involvement; she spoke no English at the time. At Chestnut Hill college she took every mathematics course offered, incl. spherical trigonometry, differential calculus, projective..

geometry, partial differential equations, and statistics, graduating as one of only a couple mathematics majors in her class of 92. With ENIAC she worked out on paper how to represent differential equations algorithmically. She invented the concept of the subroutine.

Betty Holberton, another "subprofessional" as the pay grade for human computers and programmers deemed, was known for coming up with solutions while she slept - "solved more problems in her sleep than other people did awake". She developed the concept of breakpoints, wrote the...

first generative programming language (SORT/MERGE), the first binary sort function, the driver for the first tape drives, the first statistical analysis package, helped design UNIVAC (incl. combining the number pad with the keyboard), developed the C-10 instruction set for...

BINAC that became the forerunner of modern programming languages, helped develop the standards for COBOL and FORTRAN, and even started the trend of painting computers grey-beige.

The only mathematics major in her class at Northwest Missouri State, Jean Bartik ultimately led the process of converting ENIAC from running hard-wired computer programs to stored ones to run wind tunnel simulations. Much of the code for it is in her handwriting. She also went...

on, alongside Holberton, to help develop UNIVAC and BINAC. In the 1950s, with a growing need for new programmers, she became one of the world's first programming teachers, at Remington Rand. She however had to resign when her husband took a job there, due to corporate policy.

Marlyn Meltzer (standing) only worked on ENIAC for a few years, resigning in 1947 to get married. Before joining the project, she had gotten into the role of a "human computer" via a job hand-performing weather calculations.

Frances Spence had a similar story, also resigning in 1947 due to marriage. She had a major in mathematics and a minor in physics from Chestnut Hill College .

Ruth Teitelbaum left the ENIAC team in 1948 after her marriage. During her last two years, she - like Holberton would later do at Remmington-Rand - served as a programming instructor for the next generation at Aberdeen.

The poor reputation of programming in the early ages, as merely overhead to the "real work" of designing and building computers, helped make jobs in the field accessible to women; it was not until the 1960s/1970s that the field's importance became widely appreciated on its own.