ENIAC was the world's first general purpose, electronic, digital computer. "General purpose" means that ENIAC could be reconfigured to solve a variety of problems; "electronic" means ENIAC used electronic devices (i.e., vacuum tubes instead of mechanical methods like the relay switches that were used on most previous computers) for the actual computations; and "digital" means that ENIAC performed computations in discrete steps, unlike the analog computers prevalent at that time. ENIAC is the acronym for Electronic Numerical Integrator and Computer.

Although built by a team of specialists, ENIAC was largely the product of the vision and efforts of physicist John Mauchly and electrical engineer J. Presper Eckert. Both men had joined the University of Pennsylvania's Moore School of Engineering in 1941. Mauchly had been obsessed with the idea of a better computing machine since the mid-1930s. Prior...