We present an extract from Irish STEM Lives, the new book in the Dictionary of Irish Biography (DIB) lives series, published by the Royal Irish Academy.
Edited by Turlough O'Riordan and Jane Grimson, Irish STEM Lives retraces the extraordinary work and contributions of natural philosophers, mathematicians, engineers, particle physicists, code breakers and many more. Below is an edited extract of the entry on pioneering computer programmer Kay McNulty, one of sixteen women in the collection of 46 lives.
Kay McNulty
Pioneering computer programmer Kathleen Rita ('Kay') McNulty was born on 12 February 1921 in Feymore, Creeslough, Co. Donegal, the third of six children (three boys and three girls) of James McNulty (1890–1977) and his wife Anne or Annie (née Nelis). Around 1908 James McNulty emigrated from Creeslough to Philadelphia.
Involved in Clan na Gael, he returned to Creeslough in 1915 to take part in the struggle for Irish independence. After the rising, he continued to recruit and organise Volunteers. He also worked with the local Sinn Féin club, helping to establish Doe Cooperative Society in Creeslough in 1920. In active service with the IRA he organised the sabotage of a railway bridge outside Creeslough (7 February 1921); fifteen British soldiers were injured in the resulting derailment. Arrested the day after his daughter was born, he was imprisoned until December 1921. He opposed the Anglo–Irish treaty and, unwilling to recognise the new government of the Irish Free State, returned to Philadelphia in 1923. In October 1926 the family followed him.
The McNulty household in Chestnut Hill, Philadelphia, was Irish-speaking, and Kay first learned English from her two older brothers (she remembered her prayers in Irish for the rest of her life). She attended the parish grade school and then Hallahan Catholic Girls’ High School. Chestnut Hill College offered her a scholarship, and she graduated in spring 1942, having majored in mathematics. By then the US army had a pressing need for mathematicians to produce ballistics calculations and, with a scarcity of trained men, McNulty was one of a number of women taken on to work as ‘computers’ at the Moore School of Electrical Engineering at the University of Pennsylvania.
Calculating missile trajectories, using the desk calculators and tables then available, took each woman about forty hours, and hundreds of such calculations were required. McNulty and another woman were trained to use a recently built differential analyser machine (an analogue device, reliant on mechanical operations), which speeded up calculations. A much more sophisticated machine, designed on quite novel principles, using electrical circuits to execute calculations, was being developed in great haste at the army’s Aberdeen Proving Ground in Maryland. In June 1945, McNulty was one of six women selected to work on this room-sized ENIAC (Electronic Numerical Integrator and Computer). For the next few months, the women collaborated with the engineers who were still working on the design and construction of ENIAC; there were no manuals, only design blueprints, as the machine was still incomplete.
but quickly learned English and went on to earn a degree in mathematics
McNulty and others devised the processing routines that enabled the machine to carry out calculations, more or less establishing the ways in which artificial intelligence subsequently developed. ENIAC had no memory capabilities: its programmes had to be input manually, using punch cards and realigning wiring and switches, for each calculation.
McNulty is credited with suggesting the concept of subroutines, in which the master programmer element of the instructions to the machine was set to trigger the reuse of sections of code, enabling the logical circuits to carry more capacity. Once they began to perform calculations on the actual machine, McNulty and her colleagues became expert in diagnosing problems and finding where the machine’s physical wiring or some of the 17,468 vacuum tubes or 5,000,000 hand-soldered connections had failed, as they did at first every few hours.
The public launch of the ENIAC machine as the first general-purpose electronic digital computer took place on 15 February 1946, causing great excitement in the scientific and business communities, as the potential importance of such machines was already evident. The event, however, relegated the women programmers to the role of hostesses, and official reports and early histories of computing made no mention of female operators. Tellingly, as mid-century America reversed the gains made in wartime by women in employment, science and public engagement, some contemporary observers even regarded the women in the project as ‘refrigerator ladies’: models employed to stand elegantly in front of machines that they did not understand. (Even in 1986, five of the women who had first programmed the ‘beast’ were not invited to the fortieth anniversary celebration of the birth of the electronic computing age. Kay McNulty was there, and gave an address, but did so as the widow of one of the men who had developed ENIAC.)
On 7 February 1948 Kay McNulty married John Mauchly. John Mauchly was one of the engineers chiefly responsible for designing the hardware of ENIAC; his first wife, also a gifted mathematician, had worked with him, but drowned while on holiday in 1946. Mauchly was also suffering chronic illness, hereditary haemorrhagic telangiectasia (which all but one of his and Kay’s five children inherited), necessitating constant vigilance and frequent hospitalisation; he later developed diabetes.
Until her marriage, McNulty had continued to work on ENIAC through 1947 and 1948, testing the device during its reassembly after a move to the Aberdeen Proving Ground. It is possible she was also involved in its development into a machine with a rudimentary capacity to store an operating system. In her autobiography, Kay noted without comment that her new husband gave her a cookbook on their honeymoon, and that she was thereafter expected to be the family cook; she left paid scientific work on her marriage.
The DIB, an authoritative reference work of nearly 11,000 lives for scholars of Irish history, society and culture, is published by the Royal Irish Academy - the DIB entry of Kay McNulty was authored by Dr Linda Lunney. Find out more information on Irish STEM Lives here
