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Int 21 Fn 32 - DOS 2+ - Get Dos Drive Parameter Block For Specific Drive [D]
AH = 32h
DL = drive number (00h = default, 01h = A:, etc)
Return: AL = status
00h successful
DS:BX -> Drive Parameter Block (DPB) for specified drive
FFh invalid or network drive
Notes: the OS/2 compatibility box supports the DOS 3.3 version of this call
except for the DWORD at offset 12h
this call updates the DPB by reading the disk; the DPB may be accessed
via the DOS list of lists (see AH=52h) if disk access is not
desirable.
undocumented prior to the release of DOS 5.0; only the DOS 4+ version
of the DPB has been documented, however
supported by DR-DOS 3.41+; DR-DOS 3.41-6.0 return the same data as
MS-DOS 3.31
See Also: AH=1Fh,AH=52h
Format of DOS Drive Parameter Block:
Offset Size Description
00h BYTE drive number (00h = A:, 01h = B:, etc)
01h BYTE unit number within device driver
02h WORD bytes per sector
04h BYTE highest sector number within a cluster
05h BYTE shift count to convert clusters into sectors
06h WORD number of reserved sectors at beginning of drive
08h BYTE number of FATs
09h WORD number of root directory entries
0Bh WORD number of first sector containing user data
0Dh WORD highest cluster number (number of data clusters + 1)
16-bit FAT if greater than 0FF6h, else 12-bit FAT
0Fh BYTE number of sectors per FAT
10h WORD sector number of first directory sector
12h DWORD address of device driver header
16h BYTE media ID byte
17h BYTE 00h if disk accessed, FFh if not
18h DWORD pointer to next DPB
---DOS 2.x---
1Ch WORD cluster containing start of current directory, 0000h=root,
FFFFh = unknown
1Eh 64 BYTEs ASCIZ pathname of current directory for drive
---DOS 3.x---
1Ch WORD cluster at which to start search for free space when writing
1Eh WORD number of free clusters on drive, FFFFh = unknown
---DOS 4.0-6.0---
0Fh WORD number of sectors per FAT
11h WORD sector number of first directory sector
13h DWORD address of device driver header
17h BYTE media ID byte
18h BYTE 00h if disk accessed, FFh if not
19h DWORD pointer to next DPB
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
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