NAME
       GiveUnit - Free the disk back up

   SYNOPSIS
       GiveUnit(), DRResource
                    A6

        void GiveUnit();

   FUNCTION
        This routine frees the disk after a driver is done with it.
        If others are waiting, it will notify them.

   INPUTS

   RESULTS

   EXCEPTIONS

   SEE ALSO
        getunit()

   BUGS
        In pre-V36, GiveUnit didn't check if you owned the unit.  A patch
        for this was part of 1.3.1 SetPatch.  Fixed in V36.