INT 2F - xDISK v3.32+ - INSTALLATION CHECK                                      
	AH = DDh
	BX = 7844h ('xD')
	CX = 4953h ('IS')
	DX = 4B3Fh ('K?')
	AL = desired drive (01h-1Ah) or 00h to check for xDISK on any drive
	ES:DI -> 25-byte data buffer (see #03099)
Return: AX = DDFFh if installed (on specified drive if AL nonzero on entry)
	   BX = 87BBh
	   DX = B4C0h
	   ES:DI buffer filled
	CX,CF destroyed
SeeAlso: INT 21/AX=4404h"xDISK",INT 21/AX=4405h"xDISK"


Format of xDISK data buffer:
Offset	Size	Description	(Table 03099)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	pointer to ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. driver signature "xDISK unit: X"
 04h	BYTE	flag: 01h if disk linked to DOS, 00h if unlinked
 05h	BYTE	flag: 01h if write protected, 00h if not
 06h	BYTE	flag: 01h if root directory full, 00h if not
 07h	BYTE	flag: 01h if free space uncompacted, 00h if compacted
 08h	BYTE	resizing state: 00h not resizable, 01h resized, 80h resizable
 09h	BYTE	flag: 01h inelastic resizable disk, 00h elastic
 0Ah  2 BYTEs	reserved
 0Ch	BYTE	flag: 01h collapsed disk, 00h not collapsed
 0Dh	BYTE	flag: 01h using all EMSsee Expanded Memory Specification, 00h some EMSsee Expanded Memory Specification free
 0Eh	BYTE	flag: 01h password enabled, 00h disabled
 0Fh	BYTE	flag: 01h password audio feedback, 00h no feedback
 10h	BYTE	flag: 01h password video feedback, 00h no feedback
 11h	BYTE	flag: 01h confirm changes, 00h no confirmation
 12h	BYTE	flag: 01h terse display, 00h verbose display
 13h	BYTE	flag: 01h click speaker on disk access, 00h no click
 14h	BYTE	flag: 01h flash icon on disk access, 00h no icon flash
 15h	BYTE	FATsee File Allocation Table entry size: 00h 12-bit, FFh 16-bit
 16h	WORD	count of open files in RAM(Random Access Memory)	See also DRAM, SRAM. disk
 18h	BYTE	unused