I am a bit surprised Richard Feynman does not figure in this discussion possibly because he existed "before PC". Paul Graham in his essay "The Word 'hacker'" writes [0]

    Believe it or not, the two senses of "hack" are also 
    connected. Ugly and imaginative solutions have something 
    in common: they both break the rules. And there is a 
    gradual  continuum between rule breaking that's merely 
    ugly (using duct tape to attach something to your bike) 
    and rule breaking that is brilliantly imaginative 
    (discarding Euclidean space).


    Hacking predates computers. When he was working on the
    Manhattan Project, Richard Feynman used to amuse himself 
    by breaking into safes containing secret documents. This 
    tradition continues today. When we were in grad school, a 
    hacker friend of mine who spent too much time around MIT 
    had his own lock picking kit. (He now runs a hedge fund, 
    a not unrelated enterprise.)

[0] http://www.paulgraham.com/gba.html