WWII, Grace Hopper with Harvard Mark 1 Computer, 1944

Grace Hopper and Howard Hathaway Aiken (bottom center) with unidentified members of the Bureau of Ordnance Computation Project, sitting in front of the Harvard Mark 1 computer. The IBM Automatic Sequence Controlled Calculator (ASCC), called Mark I by Harvard UniversityE??s staff, was a general purpose electromechanical computer that was used in the war effort during the last part of WWII. One of the first programs to run on the Mark I was initiated on March 29, 1944 by John von Neumann. At that time, von Neumann was working on the Manhattan project, and needed to determine whether implosion was a viable choice to detonate the atomic bomb that would be used a year later. The Mark I also computed and printed mathematical tables. The Mark I had 60 sets of 24 switches for manual data entry and could store 72 numbers, each 23 decimal digits long. It could do 3 additions or subtractions in a second. A multiplication took 6 seconds, a division took 15.3 seconds, and a logarithm or a trigonometric function took over one minute. The first programmers of the Mark I were computing pioneers Richard Milton Bloch, Robert Campbell, and Grace Hopper

Picture No

12697488

Media ID

47704444

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4500px x 3124px (2.1MB)

Credit

Smithsonian Libraries/Science Source/Mary Evans

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