Whatever device you are viewing this on-desktop computer, laptop, mobile device, tablet, internet-enabled television-your device owes a large debt of gratitude to ENIAC, Electronic Numerical Integrator And Computer, announced on the evening of February 14, 1946 and first demonstrated to the public on February 15, 1946. ENIAC was financed and designed by the United States Army Ballistics Research Laboratory, and one of its first tasks was to compute the feasibility of the hydrogen bomb. As part of an effort to ‘jump start’ the field of computing, the Pentagon invited the top researchers to give a series of 48 lectures titled The Theory and Techniques for Design of Digital Computers, of which about half were given by people who worked on ENIAC.
How big was ENIAC? ENIAC weighed more than 27 tons, and occupied a space in a room that was roughly 8 by 3 by 100 feet. ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 10,000 capacitors, 70,000 resistors, and around 5 million solder joints, each one done by hand. ENIAC consumed 150 kW of power- so much power that there was a rumor that whenever the computer was switched on, lights in Philadelphia dimmed. ENIAC was largely programmed by women, namely (using their names at the time) Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas and Ruth Lichterman. These six were inducted into the Women in Technology in 1997 for their contributions. ENIAC remained in service at the Aberdeen Proving Grounds in Maryland for almost a decade, until November 1955.
On the left: Betty Jennings (Mrs. Bartik) and on the right: Frances Bilas (Mrs. Spence) operating ENIAC’s main control panel while the machine was still located at the Moore School. Image courtesy U.S. Army Photo, from the archives of the ARL Technical Library in the pubic domain.