Electronic Numerical Integrator and Computer (ENIAC) was the worlds first programmable computer.
At first, “computer” was a profession, a person who fit into a loop to calculate things systematically. It took a group of human computers 30-40 hours to calculate a single ballistic missile trajectory. Women mathematicians were recruited because men had already been recruited.
Six out of eighty women in this profession (Kathleen Antonelli, Jean Bartik, Betty Holberton, Marlyn Meltzer, Frances Spence, and Ruth Teitelbaum), were selected to provide the step by step programming for ENIAC.