The first programmers

The first programmers were six women — Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman — hired in 1945 to program ENIAC, the first general-purpose electronic computer. They invented programming as a job while doing it: there were no languages, no manuals, no teachers — just 40 panels of hardware and the problem of making it compute.

Before them

Before 1945, "computer" was a person. The US Army's Ballistic Research Laboratory employed a corps of around eighty women — "computers," the job title — who computed artillery firing tables by hand and with desk calculators. Each table took days; the war effort needed hundreds.

When John Mauchly and J. Presper Eckert built ENIAC at the University of Pennsylvania's Moore School, the machine promised to do in seconds what hand computers took days to finish. But someone had to tell it what to do — and nobody yet knew how. The Army selected six of its human computers to find out.

Learning the machine

ENIAC was programmed by physically configuring it: routing signals through plugboards, setting thousands of switches, wiring "digit trays," and arranging the machine's twenty accumulators into a plan of execution. A "program" was a wiring diagram plus a settings table — a single ballistic trajectory could take weeks to configure, then run in minutes.

The six women were given block diagrams of the hardware and told to figure it out. They taught themselves the machine's behavior, devised flowcharts, invented debugging practices, and developed the habits — subroutines, careful state tracking, verification by hand-simulation — that programming still runs on. Adele Goldstine, who trained them, wrote the only documentation ENIAC ever had.

Their first real program was not even artillery: it was a classified hydrogen-bomb feasibility calculation run for Los Alamos in late 1945 — before ENIAC's public unveiling on 15 February 1946. When the press photographed the machine, the women operating it were labeled "refrigerator ladies" or simply cropped from the story — the assumption was that they were decoration. They were the programmers.

Recognition

For decades the six were largely invisible: histories named the hardware and its male designers, and the programming was remembered as clerical work. Historian Kathy Kleiman's research — and her book Proving Ground and documentary The Computers — recovered their names and showed that ENIAC's software problem was solved by six mathematicians teaching themselves a machine no one had ever programmed.

Today they are recognized as what they were: the first programmers of a general-purpose electronic computer.

The six

• Kay McNulty — Irish-born mathematician; later married John Mauchly.
• Betty Jennings — the team's technical anchor; went on to lead programming at UNIVAC.
• Betty Snyder — computing pioneer; invented the breakpoint and helped shape COBOL.
• Marlyn Wescoff — Temple math graduate; later became a rabbi.
• Fran Bilas — created ENIAC's first sort routines and program checks.
• Ruth Lichterman — traveled with ENIAC to Aberdeen and taught the next generation.

See also

• History of Programming
• Punched card
• Herman Hollerith
• JoAnn H. Morgan — the woman who followed them into the launch room: Apollo 11's only female controller

References

1. Kleiman, Kathy. Proving Ground: The Untold Story of the Six Women Who Programmed the World's First Modern Computer (Grand Central, 2022).
2. Haigh, Thomas, Mark Priestley, and Crispin Rope. ENIAC in Action: Making and Remaking the Modern Computer (MIT Press, 2016).
3. Evans, Claire L. Broad Band: The Untold Story of the Women Who Made the Internet (Portfolio, 2018).
4. Honeywell v. Sperry Rand, 180 U.S.P.Q. 673 (D. Minn. 1973) — the ENIAC patent trial.