Short answers, pulled from the story.
The Electronic Numerical Integrator and Computer, known as ENIAC, was the first electronic general-purpose digital computer to be completed. It was finished in 1945 and combined programmability, electronic speed, and general-purpose calculation into a single device.
John Mauchly and J. Presper Eckert designed and built the ENIAC computer. The team of design engineers included Robert F. Shaw, Jeffrey Chuan Chu, Thomas Kite Sharpless, Frank Mural, Arthur Burks, Harry Huskey, and Jack Davis.
Six women were chosen to be the programmers of the ENIAC computer: Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman. These women were highly trained mathematicians who studied the machine's logic, physical structure, operation, and circuitry.
The completed ENIAC machine was announced to the public the evening of the 14th of February 1946. A press conference was held on the 1st of February 1946, and the machine was formally dedicated the next day at the University of Pennsylvania.
The first problem assigned to the ENIAC computer was the hydrogen bomb. In December 1945, the ENIAC was used to calculate thermonuclear reactions using equations to support research on building a hydrogen bomb.
The ENIAC computer was in continuous operation until 11:45 p.m. on the 2nd of October 1955, when it was retired in favor of the more efficient EDVAC and ORDVAC computers. It was transferred to Aberdeen Proving Ground in Aberdeen, Maryland in 1947.