From Vacuum Tubes to Microchips

Hungarian-American mathematician John von Neumann, already renowned for contributions to quantum mechanics, game theory, and the Manhattan Project, became involved with the ENIAC team at the University of Pennsylvania in 1944. In 1945, he authored the "First Draft of a Report on the EDVAC," a document describing a computer architecture in which both program instructions and data are stored together in the same electronic memory, rather than instructions being fixed by physical wiring as in ENIAC. This stored-program concept, now commonly called the von Neumann architecture, allowed a computer to be reprogrammed simply by loading new instructions into memory, dramatically increasing flexibility and speed. The design specified core components, including an arithmetic-logic unit, a control unit, memory, and input and output mechanisms, an organizational structure that remains recognizable in nearly all computers built since. Although the report bore only von Neumann's name, much of the underlying design work had been developed collaboratively with Eckert, Mauchly, and other members of the Moore School team, a point of long-running historical dispute over proper credit. The EDSAC, built at the University of Cambridge under Maurice Wilkes and operational in 1949, is generally regarded as the first practical computer to fully implement the stored-program design.