INT 21 - Windows95 - FAT32 - "Get_ExtDPB" - GET EXTENDED DPBsee Drive Paramter Block
	AX = 7302h
	DL = drive number (00h=default, 01h=A:, etc.)
	ES:DI -> buffer for returned data (see #01786)
	CX = length of buffer (003Fh for Windows95)
	SI = signature (undocumentedInformation about a product which is not publicly available from the manufacturer, and must be determined by reverse-engineering (disassembly, trial-and-error, etc.).	 Undocumented information tends to change -- often dramatically -- between successive revisions of a product, since the manufacturer has no obligation to maintain compatibility in behavior which is not explicitly stated., must be F1A6h to get device driver
	      address and next-DBP pointer) (see #01787)
Return: CF clear if successful
	    ES:DI buffer filled
	CF set on error
	    AX = error code
	       0018h bad buffer length
SeeAlso: AX=7303h,AX=7304h,AH=1Fh,AH=32h


Format of Get_ExtDPB data buffer:
Offset	Size	Description	(Table 01786)
 00h	WORD	(call) length of following data (003Dh)
 02h 61 BYTEs	(ret) drive parameter block (DPBsee Drive Paramter Block) (see #01787)
 

Format of Extended Drive Parameter BlockThe DOS Drive Parameter Block stores the description of the media layout for a logical drive, as well as some housekeeping information.  See also INT 21h Function 1Fh and INT 21h Function 32h.:
Offset	Size	Description	(Table 01787)
 00h 24 BYTEs	standard DOS 4+ DPBsee Drive Paramter Block
 18h	BYTE	"dpb_flags" (undocumentedInformation about a product which is not publicly available from the manufacturer, and must be determined by reverse-engineering (disassembly, trial-and-error, etc.).	 Undocumented information tends to change -- often dramatically -- between successive revisions of a product, since the manufacturer has no obligation to maintain compatibility in behavior which is not explicitly stated.)
		FFh force media check
 19h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	pointer to next DPBsee Drive Paramter Block (see note)
 1Dh	WORD	cluster at which to start search for free space when writing,
		usually the last cluster allocated
 1Fh	WORD	number of free clusters on drive, FFFFh = unknown
 21h	WORD	high word of free cluster count
 23h	WORD	active FATsee File Allocation Table/mirroring
		bit 7: do not mirror active FATsee File Allocation Table to inactive FATs
		bits 6-4: reserved (0)
		bits 3-0: the 0-based FATsee File Allocation Table number of the active FATsee File Allocation Table
		    (only meaningful if mirroring disabled)		
 25h	WORD	sector number of file system information sector, or
		  FFFFh for none (see also #01788)
 27h	WORD	sector number of backup boot sector, or FFFFh for none
 29h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	first sector number of the first cluster
 2Dh	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	maximum cluster number
 31h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	number of sectors occupied by FATsee File Allocation Table
 35h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	cluster number of start of root directory
 39h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	cluster number at which to start searching for free space
Notes:	except for offset 18h, all of the first 33 bytes are identical to
	  the standard DOS 4-6 DPBsee Drive Paramter Block
	unless the proper value is given in SI on entry to "Get_ExtDBP", the
	  next-DPB pointer and device driver address are set to 0000h:0000h
SeeAlso: #01786,#01395 at AH=32h,#01664


Format of File System Information structure:
Offset	Size	Description	(Table 01788)
 00h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	signature 61417272h
 04h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	number of free clusters (FFFFFFFFh if unknown)
 08h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	most recently allocated cluster
 0Ch 12 BYTEs	reserved
SeeAlso: #01787