The Jargon File (version 4.4.7, 29 Dec 2003):

gronk
 /gronk/, vt.

    [popularized by Johnny Hart's comic strip B.C.: but the word apparently
    predates that]

    1. To clear the state of a wedged device and restart it. More severe than
    ?to frob? (sense 2).

    2. [TMRC] To cut, sever, smash, or similarly disable.

    3. The sound made by many 3.5-inch diskette drives. In particular, the
    microfloppies on a Commodore Amiga go ?grink, gronk?.


The Free On-line Dictionary of Computing (30 December 2018):

gronk

   /gronk/ Popularised by Johnny Hart's comic strip "B.C." but
   the word apparently predates that.

   1. To clear the state of a wedged device and restart it.
   More severe than "to frob" (sense 2).

   2. [TMRC] To cut, sever, smash, or similarly disable.

   3. The sound made by many 3.5-inch diskette drives.  In
   particular, the microfloppies on a Commodore Amiga go
   "grink, gronk".

   [Jargon File]