Int 60 Fn 12  - 3com, 10net, Banyan Vines - Lock                           [N]

   AH = 12h
   AL = drive number or 00h
   ES:SI = Ethernet address or 0000h:0000h
   DS:BX -> 31-byte ASCIZ semaphore name

Return: AL = status (see also #2985)
       01h semaphore currently locked by another PC

Note:  unlike function 11h, this function returns immediately

See Also: AH=11h,AH=13h