The programmers of the ENIAC computer in 1944, were six female mathematicians; Marlyn Meltzer, Betty Holberton, Kathleen Antonelli, Ruth Teitelbaum, Jean Bartik, and Frances Spence who were human computers at the Moore School's computation lab. Adele Goldstine was their teacher and trainer and they were known as the "ENIAC girls." The women who worked on ENIAC were warned that they would not be promoted into professional ratings which were only for men. Designing the hardware was "men's work" and programming the software was "women's work." Sometimes women were given blueprints and wiring diagrams to figure out how the machine worked and how to program it. They learned how the ENIAC worked by repairing it, sometimes crawling through the computer, and by fixing "bugs" in the machinery. Even though the programmers were supposed to be doing the "soft" work of programming, in reality, they did that and fully understood and worked with the hardware of the ENIAC. When the ENIAC was revealed in 1946, Goldstine and the other women prepared the machine and the demonstration programs it ran for the public. None of their work in preparing the demonstrations was mentioned in the official accounts of the public events. After the demonstration, the university hosted an expensive celebratory dinner to which none of the ENIAC six were invited.