Int 20  P - Microsoft Windows - Vfbackup - Vxd Services                    [W]

   VxD = 0036h

Note:  the desired VxD and service number are identified by the data
     immediately following the INT 20 instruction, as in:
       INT 20h
       DW  service number
       DW  VxD identifier

See Also: INT 2F/AX=1684h"DEVICE API",INT 30"Windows",#0961,#1032

(Table 0995)
Values for VFBACKUP (VxD ID 0036h) service number:
 0000h get version

   Return: CF clear
       EAX = version (AH = major, AL = minor)
 0001h "VFBACKUP_Lock_NEC"
 0002h "VFBACKUP_UnLock_NEC"
 0003h "VFBACKUP_Register_NEC"
 0004h "VFBACKUP_Register_VFD"
 0005h "VFBACKUP_Lock_All_Ports"

See Also: #0993,#0996