Kathleen Antonelli

The starting pay was $1620 annually.

Antonelli stated the pay was "very good at the time".

They were notified to report to work at the Moore School of Engineering.

Their job was to compute ballistics trajectories used for artillery firing tables, mostly using mechanical desk calculators and extremely large sheets of columned paper.

The pay was low, but both Antonelli and Bilas were satisfied to have attained employment that used their educations and that served the war effort.

Her official civil service title, as printed on her employment documentation, was "computer."

She and Bilas began work with about 10 other "girls" (as the female computers were called ) and 4 men—a group recently brought to the Moore School from Aberdeen Proving Ground.

Kathleen Rita Antonelli ( McNulty; formerly Mauchly; 12 February 1921 – 20 April 2006), known as Kay McNulty, was an Irish computer programmer and one of the six original programmers of the ENIAC, one of the first general-purpose electronic digital computers.

The other five ENIAC programmers were Betty Holberton, Ruth Teitelbaum, Frances Spence, Marlyn Meltzer, and Jean Bartik.

She was born Kathleen Rita McNulty in Feymore, part of the small village of Creeslough in what was then a Gaeltacht area (Irish-speaking region) of County Donegal in Ulster, the northern province in Ireland, on February 12, 1921, during the Irish War of Independence.

She was the third of six children of James and Anne (née Nelis) McNulty.

On the night of her birth, her father, an Irish Republican Army training officer, was arrested and imprisoned in Derry Gaol for two years as he was a suspected member of the IRA.

On his release, the family emigrated to the United States in October 1924 and settled in the Chestnut Hill section of Philadelphia, Pennsylvania, where he found work as a stonemason.

At the time, Kathleen McNulty was unable to speak any English, only Irish; she would remember prayers in Irish for the rest of her life.

She attended parochial grade school in Chestnut Hill (1927–1933) and J. W. Hallahan Catholic Girls High School (1933–1938) in Philadelphia.

In high school, she had taken a year of algebra, a year of plane geometry, a second year of algebra, and a year of trigonometry and solid geometry.

After graduating high school, she enrolled in Chestnut Hill College for Women.

During her studies, she took every mathematics course offered, including spherical trigonometry, differential calculus, projective geometry, partial differential equations, and statistics.

Despite all their coursework, their mathematics training had not prepared Antonelli and Bilas for their work calculating trajectories for firing tables: they were both unfamiliar with numerical integration methods used to compute the trajectories, and the textbook lent to them to study from (Numerical Mathematical Analysis, 1st Edition by James B. Scarborough, Oxford University Press, 1930) provided little enlightenment.

The two newcomers ultimately learned how to perform the steps of their calculations, accurate to ten decimal places, through practice and the advisement of a respected supervisor, Lila Todd.

A total of about 75 female computers were employed at the Moore School in this period, many of them taking courses from Adele Goldstine, Mary Mauchly, and Mildred Kramer.

Each gun required its own firing table, which had about 1,800 trajectories.

Computing just one trajectory required approximately 30–40 hours of handwork with a calculator.

After two or three months, Antonelli and Bilas were moved to work on the differential analyser in the basement of the Moore School, the largest and most sophisticated analogue mechanical calculator of the time, of which there were only three in the United States and five or six in the world (all of the others were in Great Britain).

The analyser had been lent to the University of Pennsylvania for the duration of the war.

Using the analyser (invented by Vannevar Bush of MIT a decade prior and made more precise with improvements by the Moore School staff), a single trajectory computation—about 40 hours of work on a mechanical desk calculator—could be performed in about 50 minutes.

Antonelli was further promoted to supervising calculations on the analyser.

The analyser room staff worked six days a week, with their only official holidays as Christmas and the Fourth of July.

She graduated with a degree in mathematics in June 1942, one of only a few mathematics majors out of a class of 92 women.

During her third year of college, McNulty was looking for relevant jobs, knowing that she wanted to work in mathematics but did not want to be a school teacher.

She learned that insurance companies' actuarial positions required a master's degree; therefore, feeling that business training would make her more employable, she took as many business courses as her college schedule would permit: accounting, money and banking, business law, economics, and statistics.

A week or two after graduating, she saw a US Civil Service ad in The Philadelphia Inquirer looking for women with degrees in mathematics.

During World War II, the US Army was hiring women to calculate bullet and missile trajectories at Ballistic Research Laboratory, which had been established at the Aberdeen Proving Ground in Aberdeen, Maryland, with staff from both the Aberdeen Proving Ground and the Moore School of Engineering at the University of Pennsylvania.

She immediately called her two fellow math majors, Frances Bilas and Josephine Benson about the ad. Benson couldn't meet up with them, so Antonelli and Bilas met in Philadelphia one morning in June 1942 for an interview in a building on South Broad Street (likely the Union League of Philadelphia Building).

One week later, they were both hired as human "computers" at a pay grade of SP-4, a subprofessional civil service grade.

The Electronic Numerical Integrator And Computer was developed for the purpose of performing these same ballistics calculations between 1943 and 1946.

In June 1945, Antonelli was selected to be one of its first programmers, along with several other women from the computer corps: Betty Snyder, Marlyn Wescoff, and Ruth Lichterman, and a fifth computer named Helen Greenman.

When Greenman declined to go to Aberdeen for training and a 1st alternate refused as well, Betty Jean Jennings, the 2nd alternate, got the job, and between June and August 1945 they received training at Aberdeen Proving Ground in the IBM punched card equipment that was to be used as the I/O for the ENIAC.

Later, Antonelli's college schoolmate and fellow computer, Bilas, would join the team of ENIAC programmers at the Moore School, though she did not attend the initial training at Aberdeen.

Antonelli and Bilas conducted their work in a large, former classroom in the Moore School; the same room would later be The One where the ENIAC was built and operated until December 1946.