ENIAC, 1946 Regarded as the first general purpose electronic computer, the Electronic Numerical Integrator and Computer (ENIAC) was initially commissioned for the use in World War II, but not completed until one year after the war had ended . Installed at the University of Pennsylvania, its 40 separate eight-foot-high racks and 18,000 tubes were intended to help calculate ballistic trajectories.
John Von Neumann and his machine at Princeton Institute of Advanced Studies. Used Williams tubes (CRTs) as memory devices, but used his stored-program concept, thus modern systems are mostly based on Von Neumann architecture. Photo from Computer History Museum