Admiral Grace Hopper was a computer pioneer. She wrote the first linker and one of the first compilers; was a proponent of human-readable computer languages, machine-independence of languages, and standardization; and was called "grandma COBOL". She found the first physical computer bug and worked for Univac. After retirement, she was a popular speaker on the history of computing.

During World War II, Hopper enlisted as a lieutenant junior grade in the U.S. Naval Reserves. She was assigned to the programming staff of the Bureau of Ships Computation Project at Harvard University, working on the Mark I computer. What was the function of the Navy computer programs that Hopper worked on during World War II? (Ballistic trajectory? Fluid dynamics? Decryption? Inventory management? Payroll?)

  • 2
    When talking about the Aiken Mark I, it's important to keep in mind that it was much more like an automated calculator than a computer - like the Zuse Z1. So programming was mostly linear translation of equation and automated calculation thereof. Way different from what programming became right after the war. So yes, ballistics and similar computations were the task of the day. Everything else mentioned would need some kind of database and data in/output for (automatic) repeated processing. So noting we would call computing today. Just lengthy calculations.
    – Raffzahn
    Commented Jul 22, 2021 at 23:14
  • I am currently rating the Book Broad Band from Claire Evans, it has a chapter on Admiral Hoppers early days up to the COBOL times.
    – eckes
    Commented Jul 23, 2021 at 6:33

1 Answer 1


From https://president.yale.edu/biography-grace-murray-hopper:

Under the guidance of Howard Aiken, who had developed the MARK I, Hopper and her colleagues worked on top-secret calculations essential to the war effort—computing rocket trajectories, creating range tables for new anti-aircraft guns, and calibrating minesweepers. One of the first three “coders” (now known as programmers), Hopper also wrote the 561-page user manual for the MARK I.

https://www.pbs.org/wgbh/aso/databank/entries/btmurr.html suggests that "calibrating minesweepers" was about making "fast, difficult calculations for tasks such as laying mine fields."

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    I get it, there was Minesweeper on the MARK 1 already. Sure, required for (scare quotes) war effort ;-)
    – Edheldil
    Commented Jul 23, 2021 at 13:03
  • 2
    So she beat Microsoft for writing the first Minesweeper program? ;^)
    – DrSheldon
    Commented Jul 23, 2021 at 20:46
  • Hmmm, calibration sounds more like demag, although I have no idea why you would need a computer for that. Commented Jul 28, 2021 at 18:36

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