EDVAC (Electronic Discrete Variable Automatic Computer). Technicians working on EDVAC, one of the earliest electronic computers, operational 1951-61. EDVAC was designed and built by the University of Pennsylvania for the US Army's Ballistics Research Laboratory (BRL) to replace the earlier digital calculator, ENIAC. Unlike ENIAC, EDVAC used the binary numerical system, and its programs and working data were both stored in a single store. EDVAC was used to calculate solutions to military problems, particularly concerning ballistics. The man operating the paper tape machine (right) is Richard Bianco, the other man is working the console or operating device.