Jean Bartik

Betty Jean Jennings grew up on a farm in Gentry County, Missouri, the sixth of seven children, and was the only one in her maths class at the local teachers' college. In 1945 she answered an advertisement from the Army for women with mathematics degrees to work as "computers", calculating artillery firing tables by hand at the University of Pennsylvania.

There she was picked, with five other women, to make a new machine do the same job. ENIAC filled a room, weighed 30 tons and had 18,000 valves. There was no manual and no programming language. The six women learned it from wiring diagrams and interviews with the engineers, then worked out how to set up a calculation by plugging in cables and setting thousands of switches, and how to find faults down to a single failed valve.

When ENIAC was shown to the press in February 1946 it was Jennings and Betty Holberton who had made the trajectory demonstration work. The women appeared in the photographs and were not named; some later assumed they were models. They were not invited to the celebration dinner.

She married, took the name Bartik, went on to program BINAC and UNIVAC for Eckert and Mauchly and later worked as an editor. Her contribution was rediscovered by a Harvard student in the 1980s. She was named a Fellow of the Computer History Museum in 2008, three years before she died.