Int 2F Fn 110A  CU - Network Redirector (dos 4+) - Lock/unlock Region Of   [N]

   AX = 110Ah
   BL = function
       00h lock
       01h unlock
   CX = number of lock/unlock parameters (0001h for DOS 4.0-6.1)
   DS:DX -> parameter block (see below)
   ES:DI -> SFT
       SFT DPB field -> DPB of drive containing file
   SS = DOS DS

Return: CF set on error
      AL = DOS error code (see INT 21/AH=59h)

Notes: this function is called by the DOS 4.0+ kernel
   the redirector is expected to resolve lock conflicts

See Also: AX=110Bh,INT 21/AH=5Ch

Format of parameter block entry [array, but currently limited to single entry]:
Offset Size    Description
 00h   DWORD   start offset
 04h   DWORD   size of region