INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - GET OR SET LOCK MODE
        AH = C6h
        AL = subfunction
            00h set old "compatibility" mode (default)
            01h set new extended locks mode
            02h get lock mode
Return: AL = current lock mode
Note:   this function is supported by NetWare 4.6+, Advanced NetWare 1.0+, and
          Alloy NTNX
        the locking mode should be 01h for NetWare 4.61+ and Advanced
          NetWare 1.0+ locking calls, and 00h for all older calls
SeeAlso: AH=C4h,AH=D0h