INT 21 - Novell NetWare - SYNCHRONIZATION SERVICES - LOCK FILE SET
        AH = CBh
        if function C6h lock mode 00h:
            DL = mode
                00h no wait
                01h wait
        if function C6h lock mode 01h:
            BP = lock timeout in timer ticks (1/18 sec) 0000h = no wait
Return: AL = status
            00h successful
            FEh timed out
            FFh failed
Desc:   attempt to lock all files listed in the log table
Notes:  this function is supported by NetWare 4.0+, Advanced NetWare 1.0+, and
          Alloy NTNX
        status FFh will be returned if one or more of the files have already
          been exclusively locked by another process
SeeAlso: AH=CDh,AH=D1h,AH=EBh