Log physical record (INT 21h, BCh - Novell Netware 4.6)

        Entry:
          AH    = BCh
          AL    = flags
                   bit 0: lock as well as log record
                       1: non-exclusive lock
          BX    = file handle
          CX:DX = offset
          BP    = timeout in timer ticks (1/18 sec)
          SI:DI = length
        Return:
          AL = error code