Int 21/AX=440Dh

DOS 3.2+ - IOCTL - GENERIC BLOCK DEVICE REQUEST

AX = 440Dh
BL = drive number (00h=default,01h=A:,etc)
CH = category code (see #01558)
CL = minor code (function) (see #01559)
DS:DX -> (DOS) parameter block (see #01560,#01562,#01563,#01564,#01565)
SI:DI -> (OS/2 comp box) parameter block (see #01566,#01568,#01569,#01572)

Return:
CF set on error
AX = error code (01h,02h,etc.) (see #01680 at AH=59h/BX=0000h)
CF clear if successful
DS:DX -> data block if CL=60h or CL=61h

Notes: DOS 4.01 seems to ignore the high byte of the number of directory entries in the BPB for diskettes.. Functions 46h and 66h undocumented in DOS 4.x, documented for DOS 5+. The DUBLDISK.SYS v2.6 driver only supports minor codes 60h and 67h. DR DOS 3.41-6.0 only support minor codes 40h-42h and 60h-62h; all other minor codes return error code 16h. Some PCMCIA calls reportedly appear to be dangerous for MS-DOS versions prior to 5.0. Minor code 60h normally produces no I/O except with AutoMount=1 for DBLSPACE/DRVSPACE

See Also: AX=440Ch - AX=440Dh/CX=084Ah - AX=440Dh/CX=0871h

See Also: INT 2F/AX=122Bh



(Table 01558)
Values for block device IOCTL category code:
08h    disk drive
48h    FAT32 disk drive
00h-7Fh reserved for Microsoft
80h-FFh reserved for OEM/user-defined


(Table 01559)
Values for generic block IOCTL minor code:
00h    (OS/2)  \ used to lock/unlock a drive
01h    (OS/2)  /
40h    set device parameters (see #01560)
41h    write logical device track (see #01562)
42h    format and verify logical device track (see #01563)
46h    (DOS 4.0+) set volume serial number (see #01565,AH=69h)
47h    (DOS 4.0+) set access flag (see #01566)
48h    (Enh. Disk Drive Spec) set media lock state (see #01567,INT 13/AH=45h)
49h    (Enh. Disk Drive Spec) eject media in drive (see INT 13/AH=49h).
No parameter block required
4Ah    (MS-DOS 7.0) lock logical volume (see AX=440Dh/CX=084Ah)
4Bh    (MS-DOS 7.0) lock physical volume (see AX=440Dh/CX=084Bh)
50h    (PCMCIA) attribute memory write
51h    (PCMCIA) common memory write
52h    (PCMCIA) force media change (DOS 5+ ???) (see #01568)
53h    (PCMCIA) erase drive
54h    (PCMCIA) erase media
56h    (PCMCIA) set erase status callback
57h    (PCMCIA) append Card Information Structure (CIS) tuple
58h    (PCMCIA) erase CIS tuples
60h    get device parameters (see #01560)
61h    read logical device track (see #01562)
62h    verify logical device track (see #01564)
66h    (DOS 4.0+) get volume serial number (see #01565,AH=69h)
67h    (DOS 4.0+) get access flag (see #01566)
68h    (DOS 5.0+) sense media type (see #01569)
6Ah    (MS-DOS 7.0) unlock logical volume (see AX=440Dh/CX=086Ah).
No parameter block required
6Bh    (MS-DOS 7.0) unlock physical volume (see AX=440Dh/CX=086Bh).
No parameter block required
6Ch    (MS-DOS 7.0) get lock flag (see AX=440Dh/CX=086Ch).
No parameter block required
6Dh    (MS-DOS 7.0) enumerate open files (see AX=440Dh/CX=086Dh)
6Eh    (MS-DOS 7.0) find swap file (see AX=440Dh/CX=086Eh)
6Fh    (MS-DOS 7.0) get drive map information (see #01570)
70h    (PCMCIA) attribute memory read
70h    (MS-DOS 7.0) get current lock state (see AX=440Dh/CX=0870h).
No parameter block required
71h    (MS-DOS 7.0) get first cluster (see AX=440Dh/CX=0871h)
73h    (PCMCIA) get memory media information (DOS 5+ ???) (see #01572)
76h    (PCMCIA) get erase status callback
77h    (PCMCIA) get first Card Information Structure (CIS) tuple
78h    (PCMCIA) get next CIS tuple
7Fh    (PCMCIA) get ??? information (see #01573,#01574)

Format of parameter block for functions 40h, 60h:

Offset  Size    Description     (Table 01560)
00h    BYTE    special functions
bit 0 set if function to use current BPB, clear if Device
BIOS Parameter Block field contains new default BPB
bit 1 set if function to use track layout fields only
must be clear if CL=60h
bit 2 set if all sectors in track same size (should be set)
bits 3-7 reserved (MS-DOS, Novell DOS 7)
bit 5:
Skip head settling time (WinDOS 2.11)
bit 6:
Format access flag (WinDOS 2.11)
01h    BYTE    device type (see #01561)
02h    WORD    device attributes
bit 0 set if nonremovable medium
bit 1 set if door lock ("changeline") supported
bits 2-15 reserved
04h    WORD    number of cylinders
06h    BYTE    media type
for 1.2M drive
00h 1.2M disk (default)
01h 320K/360K disk
F8h for DUBLDISK.SYS v2.6 expanded drives
always 00h for other drive types
07h 31 BYTEs   device BPB (see #01663 at AH=53h), bytes after BPB offset 1Eh
omitted; final six bytes only transferred on function 40h
with BYTE 00h bit 0 set for MS-DOS 5.0
---function 40h only---
26h    WORD    number of sectors per track (start of track layout field)
(maximum 63)
28h  N word pairs:
Number,size of each sector in track
---category code 48h (FAT32), function 40h---
07h 53 BYTEs   extended BPB (see #01664)
3Ch 32 BYTEs   reserved
5Ch    WORD    number of track table entries
5Eh 2N WORDs   sector table (word pairs:
Number/size of each sector in track)
---category code 48h (FAT32), function 60h---
07h 53 BYTEs   extended BPB (see #01664)
3Ch 32 BYTEs   reserved


(Table 01561)
Values for device type:
00h    320K/360K 5.25-inch floppy disk
01h    1.2M 5.25-inch floppy disk
02h    720K floppy disk
03h    single-density 8-inch disk
04h    double-density 8-inch disk
05h    fixed disk
06h    tape drive
07h    (DOS 3.3+) other type of block device, normally 1.44M floppy
08h    read/write optical disk
09h    (DOS 5+) 2.88M 3.5-inch floppy
FFh    (some DOS 5 betas) 2.88M 3.5-inch floppy

Format of parameter block for functions 41h, 61h:

Offset  Size    Description     (Table 01562)
00h    BYTE    special functions (reserved, must be zero)
01h    WORD    number of disk head
03h    WORD    number of disk cylinder
05h    WORD    number of first sector to read/write
07h    WORD    number of sectors
09h    DWORD   transfer address

Note: Under Windows95, a volume must be locked (see AX=440Dh/CX=084Bh) in order to perform direct accesses such as track reads and writes with this IOCTL function


Format of parameter block for function 42h:

Offset  Size    Description     (Table 01563)
00h    BYTE    reserved, must be zero (DOS <3.2)
bit 0=0:
Format/verify track
1:
Format status call (DOS 3.2+), don't actually format
bit 1:
Format multiple tracks, require additional WORD
(hard disks only)
bits 2-7 reserved, must be zero
value on return (DOS 3.3+):
00h   specified tracks, sectors/track supported by BIOS
01h   function not supported by BIOS
02h   specified tracks, sectors/track not allowed for drive
03h   no disk in drive
01h    WORD    number of disk head
03h    WORD    number of disk cylinder
---BYTE 00h bit 1 set---
05h    WORD    number of tracks to format

Format of parameter block for function 62h:

Offset  Size    Description     (Table 01564)
00h    BYTE    reserved, must be zero (DOS <3.2)
bit 0=0:
Verify single track
1:
Verify multiple tracks
bits 1-7 reserved, must be zero
value on return (DOS 3.3+):
00h   specified tracks, sectors/track supported by BIOS
01h   function not supported by BIOS
02h   specified tracks, sectors/track not allowed for drive
03h   no disk in drive
01h    WORD    number of disk head
03h    WORD    number of disk cylinder
05h    WORD    number of tracks to verify (equivalent to 255 or fewer sectors)

Format of parameter block for functions 46h, 66h:

Offset  Size    Description     (Table 01565)
00h    WORD    (call) info level (should be 0000h)
02h    DWORD   disk serial number (binary)
06h 11 BYTEs   volume label or "NO NAME    "
11h  8 BYTEs   filesystem type "FAT12   " or "FAT16   "
(generally CL=66h only, but MS-DOS 5.0 will write the
given filesystem type to the disk)

Note: Under MS-DOS 7.0 or a Windows95 DOS box, the volume label field can return as all blanks even when a volume label has been set (the Win95 installation seems to blank the volume label field in the partition boot sector; once LABEL has been run, the volume label is reported correctly)

See Also: AH=69h


Format of parameter block for functions 47h, 67h:

Offset  Size    Description     (Table 01566)
00h    BYTE    special-function field (must be zero)
01h    BYTE    disk-access flag, nonzero if access allowed by driver

Format of parameter block for function 48h:

Offset  Size    Description     (Table 01567)
00h    BYTE    (call) locking operation
00h lock media in drive
01h unlock media
02h get locking status
01h    BYTE    (ret) drive's lock status (number of pending locks on drive)

Note: Also supported by MS-DOS 7.0+


Format of parameter block for function 52h:

00h    BYTE    (call) unused???        (Table 01568)
(ret) 00h if flash/ATA drive but no card inserted
unchanged otherwise

Notes: The absense of a flash card should be tested by checking the DOS error code rather than the returned byte. The parameter byte is cleared to 00h erroneously by the Award PCDISK.EXE v1.02c PCMCIA/ATA driver if no ATA card is inserted (bug corrected in PCDISK.EXE v1.02h and later). Not supported by the SystemSoft ATADRV.EXE and the Phoenix PCMATA.SYS PCMCIA/ATA drivers


Format of parameter block for function 68h:

Offset  Size    Description     (Table 01569)
00h    BYTE    01h for default media type, 00h for any other media type
(see also INT 13/AH=20h"Compaq")
01h    BYTE    02h for 720K, 07h for 1.44M, 09h for 2.88M

Format of parameter block for function 6Fh:

Offset  Size    Description     (Table 01570)
00h    BYTE    (call) length of this buffer (in bytes)
01h    BYTE    (ret) number of bytes in parameter block actually used
02h    BYTE    (ret) drive flags (see #01571)
03h    BYTE    (ret) physical drive number
00h-7Fh floppy
80h-FEh hard
FFh no physical drive
04h    DWORD   (ret) bitmap of logical drives associated with physical drive
bit 0 = drive A:, etc.
08h    QWORD   (ret) relative block address of partition start

Bitfields for Get Drive Map Information drive flags:

Bit(s)  Description     (Table 01571)
0      protected-mode driver for logical drive
1      protected-mode driver in use for physical drive corresponding to the
logical drive
2      drive available only in protected mode
3      protected-mode drive supports media ejection
4      drive issues media insertion and removal notifications

See Also: #01570

Format of parameter block for function 73h: Offset Size Description (Table 01572) 00h BYTE ??? 00h ATA card inserted ??? 80h ATA card not inserted ??? 01h BYTE length of parameter block ??? apparently always 40h 02h BYTE ??? 00h ATA card not inserted ??? 0Dh ATA card inserted ??? 03h 2 BYTEs ??? (apparently always 00h) 05h BYTE drive number (0=first) ??? 06h BYTE total number of drives ??? 07h BYTE ??? 00h ATA card not inserted ??? 01h ATA card inserted ??? 08h 17 BYTEs ??? 19h BYTE ??? 00h ATA card not inserted ??? 01h ATA card inserted ??? 1Ah BYTE ??? (apparently always 01h) 1Bh BYTE ??? 00h ATA card not inserted ??? 01h ATA card inserted ??? 1Ch 2 BYTEs ??? (apparently always 0015h) 1Eh 2 BYTEs ??? 20h 2 BYTEs ??? (apparently always 0110h) 22h 15 BYTEs ??? 31h 2 BYTEs ??? (apparently always 7000h) 33h 11 BYTEs driver signature "AWARD PDISK" for Award PCDISK.EXE PCMCIA/ATA driver "MS-BIOS " for HP 200LX generic ATA driver 3Eh 2 BYTEs ???

Notes: Parameter structure possibly depends on driver. This function is not supported by the SystemSoft ATADRV.EXE and the Phoenix PCMATA.SYS PCMCIA/ATA drivers


Format of parameter block for function 7Fh for SystemSoft ATADRV.EXE:

Offset  Size    Description     (Table 01573)
00h    DWORD   -> unknown location within driver

Note: Function supported by the SystemSoft ATADRV.EXE PCMCIA/ATA driver but not by the Award PCDISK.EXE PCMCIA/ATA driver

See Also: #01574


Format of parameter block for function 7Fh for Phoenix PCMATA.SYS:

Offset  Size    Description     (Table 01574)
00h  8 BYTEs   ???

Note: This function supported by the Phoenix PCMATA.SYS PCMCIA/ATA driver but not by the Award PCDISK.EXE PCMCIA/ATA driver

See Also: #01573

Category: DOS Kernel - Int 21h - D

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