NAME
   GetUnitID - find out what type of disk is out there
SYNOPSIS
   idtype = GetUnitID( unitNum ), DRResource
    D0                  D0         A6
    LONG GetUnitID(LONG);
FUNCTION
    Gets the drive ID for a given unit.  Note that this value may
    change if someone calls readunitid, and the drive id changes.
INPUTS
    unitNum -- a legal unit number (zero through three)
RESULTS
    idtype -- the type of the disk drive.  Standard types are
            defined in the resource include file.
EXCEPTIONS
SEE ALSO
    readunitid
BUGS