Programming the ENIAC: rewiring cables instead of writing code

Programming the ENIAC (2011)

A Columbia University history page explains how the ENIAC was programmed in the 1940s. There was no stored program: operators set switches and plugged cables to route data between accumulators and function tables, essentially rebuilding the machine's logic for each new problem. The page covers the six women who did this work and the transition to the modern stored-program model.