Ireland’s Greatest Woman Inventor finalist – Kay McNulty Mauchly Antonelli, first woman computer programmer

5 Jul 2013

Kay McNulty Mauchly Antonelli, first woman computer programmer, in her high school graduation portrait. Photo via Wikimedia Commons

Kay McNulty Mauchly Antonelli is one of the six original programmers of the ENIAC, the first general-purpose electronic digital computer.

Kathleen McNulty was born on 12 February 1921 in the Creeslough area of Co Donegal. When she was three, she moved with her family to Philadelphia, Pennsylvania, where her father James established a masonry business.

At school, Kay excelled in mathematics and she earned a degree in the subject from Chestnut Hill College for Women in 1942. Only three women in her class of 92 graduated in mathematics.

Soon afterwards, McNulty went to work for the US Army’s Ballistics Research Laboratory in Maryland. The organisation had been seeking women to work in its division at the Moore School of Electrical Engineering at the University of Pennsylvania.

The job involved calculating trajectories for shells and bullets, crucial information for soldiers using artillery guns.

McNulty eventually became a shift leader and the war effort was requiring faster calculations. J Presper Eckert, an engineer at the school, realised that analogue machines could not be pushed much further and that an electronic calculating machine – an electronic, rather than a human, computer – was the answer.

He and another engineer, John Mauchly, worked out the basic idea for the world’s first general purpose digital computer, called ENIAC (Electronic Numerical Integrator and Computer).

The resulting mammoth machine had no memory to hold instructions on how it was to perform a calculation. Instead, it had to be programmed by hand.

Because ENIAC was to be used to calculate trajectories, McNulty and five of the other best women ‘computers’ at Moore School – Jean Jennings Bartik, Frances ‘Betty’ Snyder Holberton, Marlyn Wescoff Meltzer, Frances Bilas Spence and Ruth Lichterman Teitelbaum – were transferred to work on ENIAC. Their job would be to programme ENIAC to perform the calculations.

The women essentially taught themselves how to program and ENIAC eventually performed calculations in 15 seconds.

McNulty worked on ENIAC for two more years until, in 1948, she married Mauchly and became a full-time housewife and mother to seven children. However, she continued to work with her husband on computer program designs and techniques.

Mauchly died in 1980, and in 1985, McNulty Mauchly married photographer Severo Antonelli. He died in 1996.

McNulty Mauchly Antonelli had begun to argue publicly for Mauchly and Presper Eckert’s recognition as the co-inventors of the first general purpose electronic computer and by 1984, she was in demand as a speaker on ENIAC, computing history, and the role she and her women colleagues played in the development of modern computing.  

In 1997, she was inducted into the Women in Technology International Hall of Fame. Her oral history was recorded in 1998, and is part of a documentary about the ENlAC programmers titled The Computers.

In Co Donegal, the Letterkenny Institute of Technology established an annual award for the best computer science student, the Kay McNulty medal and prize.

Antonelli died after a brief illness in Wyndmoor, Pemnnsylvania, on 20 April 2006. She was 85.

To vote for Antonelli as Ireland’s Greatest Woman Inventor, click here.

Read about the other finalists in our Ireland’s Greatest Woman Inventor competition:

Lilian Bland

Agnes Clerke

Phyllis Clinch

Margaret Lindsay Huggins

Cynthia Longfield

Kathleen Lonsdale

Annie Maunder

Dorothy Stopford Price

Alicia Boole Stott

With thanks to Mary Mulvihill of Ingenious Ireland for providing the material for this profile from her book Lab Coats and Lace (2009).

Women Invent Tomorrow is Silicon Republic’s year-long campaign to champion the role of women in science, technology, engineering and maths