资料来源 : Free On-Line Dictionary of Computing

grind crank
     
        A mythical accessory to a {terminal}.  A crank on the side of
        a monitor, which when operated makes a zizzing noise and
        causes the computer to run faster.  Usually one does not refer
        to a grind crank out loud, but merely makes the appropriate
        gesture and noise.  See {grind}.
     
        Historical note: At least one real machine actually had a
        grind crank - the R1, a research machine built toward the
        end of the days of the great vacuum tube computers, in 1959.
        R1 (also known as "The Rice Institute Computer" (TRIC) and
        later as "The Rice University Computer" (TRUC)) had a
        {single-step}/free-run switch for use when debugging programs.
        Since single-stepping through a large program was rather
        tedious, there was also a crank with a cam and gear
        arrangement that repeatedly pushed the single-step button.
        This allowed one to "crank" through a lot of code, then slow
        down to single-step for a bit when you got near the code of
        interest, poke at some registers using the console typewriter,
        and then keep on cranking.
     
        [{Jargon File}]