(Electronic Discrete Variable Automatic Computer) The successor to ENIAC, EDVAC was designed by J. Presper Eckert and John Mauchly at the University of Pennsylvania in the 1940s. Although it was the first stored program computer, it did not become operational until 1952, two years after SEAC, which was based on EDVAC designs. EDVAC was an arithmetic-only computer working with binary numbers rather than the decimal operations of ENIAC. It had 1K 44-bit words of delay line memory. See ENIAC, SEAC, early memories and early computers.