INT 21 U - IFSHLP.SYS - GET ENTRY POINT                                         
	AX = 4402h
	BX = file handle for device "IFSsee Installable File System$HLP$"
	CX = 0008h (size of buffer in bytes)
	DS:DX -> buffer for entry point record (see #01415 at AH=3Fh"IFSHLP")
Return: CF clear if successful
	    buffer filled
	CF set on error
	    AX = error code (01h,05h,06h,0Dh) (see #01680 at AH=59h/BX=0000h)
SeeAlso: AH=3Fh"IFSHLP"
                                                                                

INT 21 - DRFAT32.SYS device driver - IOCTL INPUT                                
	AX = 4402h
	BX = file handle referencing character device for DRFAT32.SYS driver
	    (e.g. "FAT32XXX" in the default configuration)
	CX = number of bytes to read
	DS:DX -> control block (see #04108)
Return: CF clear if successful
	    AX = number of bytes actually read
	CF set on error
	    AX = error code (01h,05h,06h,0Dh) (see #01680 at AH=59h/BX=0000h)
Notes:	 the data returned depends on the first byte of the control block
	   the remainder of the control block is filled by the driver
	 one DRFAT32.SYS device driver supports up to 8 subunits (that is up
	   to 8 FAT32 partitions). By default, DRFAT32.SYS logs in all FAT32
	   partitions it finds, however, by using command line options /C (CHS),
	   /L (LBA), /H (Hidden) and /P:1..4 (Primary), /E:1..255 (Logical
	   Drive), and /U:min[,max] (Unit 128..255) it can be directed to
	   attach only to one or a specific range of partitions. Multiple
	   DRFAT32.SYS drivers can be loaded in a system when using the
	   /D:name option. To assign them to the redirector, the /D:name option
	   must be repeated for each of the DRFAT32.SYS drivers in the
	   DRFAT32.EXE command line.
SeeAlso: AX=4402h"CD-ROM",INT 2F/AX=0802h


Format of DRFAT32 control block:
Offset	Size	Description	(Table 04108)
 00h	BYTE	data being requested
		00h device driver header address
		09h media change status
		48h address of DRFAT32 geometry table
		else error
---function 00h---
 01h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	device driver header address (see also AH=52h,#01646)
---function 09h---
 01h	BYTE	media change status
		00h don't know
		01h media unchanged
		FFh media has been changed
---DRFAT32 function 48h---
 01h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	address of DRFAT32 geometry table (see #04109)


Format of DRFAT32 Geometry Table:
Offset	Size	Description	(Table 04109)
 00h 8*59 BYTEs	eight DRFAT32 partition data tables (see #04110)
 1D8h	BYTE	DRFAT32 access flags (see #04111)
 1D9h	BYTE	DRFAT32 status flags (see #04112)
Note:	This is the table layout used by DRFAT32.SYS 1.00 which supports up
	  to 8 sub-units. The layout of this table and its records may change,
	  so the version indicator in the device driver's signature ("FAT320")
	  and the size of the public data structure should be checked first.
SeeAlso: #04108


Format of DRFAT32 partition data table:
Offset	Size	Description	(Table 04110)
 00h	BYTE	size of following public data structure (9)
	--- public data (needed by the DRFAT32.EXE redirector) ---
 01h	WORD	bytes per sector
 03h	BYTE	sectors per cluster
 04h	WORD	reserved sectors
 06h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	root directory start cluster
	--- private data ---
 0Ah	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	sectors per track
 0Eh	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	root directory sector
 12h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	partition start sector
 16h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	highest partition sector allowed
		(only if range checking enabled)
 1Ah	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	absolute cluster start sector
		(cluster start sector+partition start sector)
 1Eh	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	total sectors per track (number of heads * sectors per track)
 22h	BYTE	drive unit (default 80h)
 23h	BYTE	temp buffer: CHS sectors to write (if verify enabled)
 24h	BYTE	INT 13h extension version
	--- CHS data ---
 25h	WORD	cylinder
 27h	WORD	head
 29h	WORD	sector
	--- LBA data ---
 2Bh 16 BYTEs disk address packet (see #00272 at INT 13/AH=42h)
SeeAlso: #04109


Bitfields for DRFAT32 access flags:
Bit(s)	Description	(Table 04111)
 7	using LBA addressing instead of CHS
 6	using INT 13h extensions (see also INT 13/AH=48h)
 5	multi-sector access allowed
 4	force media change indication on removable drives
 3	force verify after every write (/W)
 2	more than 1024 cylinders, less than 64 heads (/A)
 1	client-side asynchronous buffering allowed (/B), normally =0
 0	read-only access (/R)
SeeAlso: #04109,#04112


Bitfields for DRFAT32 status flags:
Bit(s)	Description	(Table 04112)
 7-2	reserved (0)
 1	Save Guard enabled (blocks any further writes after a fault)
 0	volume may have dirty sectors (set after write operations)
SeeAlso: #04109,#04111