"Electronic Discrete Variable Automatic Computer"
EDVAC was one of the earliest electronic computers. Unlike its predecessor the ENIAC, it was binary rather than decimal, and was a stored-program computer. ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC's construction in August 1944. A contract to build the new computer was signed in April 1946 with an initial budget of US$100,000. EDVAC was delivered to the Ballistics Research Laboratory in August 1949. Functionally, EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory capacity of 1,000 44-bit words. EDVAC's average addition time was 864 microseconds and its average multiplication time was 2,900 microseconds. By 1960 EDVAC was running over 20 hours a day with error-free run time averaging eight hours. EDVAC ran until 1961 when it was replaced by BRLESC. During its operational life it proved to be reliable and productive for its time.