INT 2F C - MS Windows 3.1 - "BLOCKDEV" VIRTUAL HARD DISK DEVICE API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running.  Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes.
	AX = 1607h
	BX = 0010h (VxDA virtual device driver for Windows 3.x or 95.	So called because nearly all of the Windows 3.0 drivers had names of the form "VdeviceD". See also device driver. identifier of "BLOCKDEV")
	CX = function
	    0001h starting FastDisk compatibility tests
	    0002h ending FastDisk compatibility tests
	    0003h check if FastDisk installation allowed
		Return: CX = 0000h if allowed
Note:	this interface is called by the Windows FastDisk driver (such as
	  WDCTRL) when it thinks that the INT 13h handler immediately below
	  IO.SYS's INT 13h code is not in ROM(Read-Only Memory) A memory for program storage which may not be changed by the program as it runs.; it should be supported by any
	  program which hooks itself underneath IO.SYS's INT 13h code with
	  INT 2F/AH=13h
SeeAlso: AX=1607h/BX=0014h,INT 2F/AH=13h