Important people in Computer Science

List the names of important people in Computer Science and their contributions to the field. I will start.

Grace Hopper - She built the first compiler named A-0. She is credited with popularizing the term debugging, because she found a real bug (a moth) stuck in a relay therefore impeding the system.

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Yep! Stallman deserved his place right between Guido and Ballmer, for his support to Worse is Better movement. Remember, every time you see "segmentation fault" or KDE leakes a few Gb, it's Stallman, who must be praised.