Univac in 1951

UNIVAC in 1951

UNIVAC (Universal Automatic Computer), the first commercially successful computer performed a public demonstration in Philadelphia, PA. USA on this date in 1951.  J. Presper Eckert and John Mauchly spent five years designing and building UNIVAC.  Built from 5,600 vacuum tubes,  300 relays, 18,000 crystal diodes, miles of wire and a mercury acoustic delay loop for program storage, the system’s physical dimensions are 14.5 feet long by 7.5 feet wide and 8 feet tall, and required 120 kva to power it–basically a small electric power plant.  It could store about 12,000 characters in main memory.

Compare those specifications to your Kindle,  iPad or Android smartphone computing devices, which are thousands of times smaller and exponentially more powerful and run on mere milliwatts. Still, UNIVAC was able to successfully predict the result of the 1952 Presidential election which Walter Cronkite added to his election coverage for CBS.

UNIVAC was built on ones compliment logic and could process not just numeric data, but character data as well. However, ones compliment logic produces the possibility of minus zero (-0) as a result, something that had to be accounted for when writing programs for the UNIVAC.  The UNIVAC also separated input, output and computational functions from each other which is industry standard practice today. Other firsts in this computer were the ten magnetic tape readers used for information storage and retrieval, buffer memory

UNIVAC was purchased by the U.S. Government Census Bureau to process demographic data at 120 facts per second. There were 46 UNIVAC computers built and delivered between 1951 to 1958.

The UNIVAC also has the distinction of being tied to Rear Admiral Grace Hopper, the Grande Dame of computing, creator of the first compiler, the COBOL language, both developed on the UNIVAC, and the term ‘debugging’.