The ENIAC was placed in operation at the Moore School, component by
component, beginning with the cycling unit and an accumulator in June 1944.
This was followed in rapid succession by the initiating unit and function
tables in September 1945 and the divider and square-root unit in October 1945.
Final assembly took place during the fall of 1945.
By today's standards for electronic computers the ENIAC was a grotesque
monster. Its thirty separate units, plus power supply and forced-air cooling,
weighed over thirty tons. Its 19,000 vacuum tubes, 1,500 relays, and hundreds
of thousands of resistors, capacitors, and inductors consumed almost
200 kilowatts of electrical power.
But ENIAC was the prototype from which most other modern computers
evolved. It embodied almost all the components and concepts of today's high-
speed, electronic digital computers. Its designers conceived what has now
become standard circuitry such as the gate (logical "and" element), buffer
(logical "or" element) and used a modified Eccles-Jordan flip-flop as a
logical, high-speed storage-and-control device.