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Int 21 Fn 53 - DOS 2+ Internal - Translate BIOS Parameter Block To Drive [D]
AH = 53h
DS:SI -> BIOS Parameter Block (see below)
ES:BP -> buffer for Drive Parameter Block (see AH=32h for format)
Return: ES:BP buffer filled
Note: for DOS 3+, the cluster at which to start searching is set to 0000h
and the number of free clusters is set to FFFFh (unknown)
Format of BIOS Parameter Block:
Offset Size Description
00h WORD number of bytes per sector
02h BYTE number of sectors per cluster
03h WORD number of reserved sectors at start of disk
05h BYTE number of FATs
06h WORD number of entries in root directory
08h WORD total number of sectors
for DOS 4+, set to zero if partition >32M, then set DWORD at
15h to actual number of sectors
0Ah BYTE media ID byte
0Bh WORD number of sectors per FAT
---DOS 3+---
0Dh WORD number of sectors per track
0Fh WORD number of heads
11h DWORD number of hidden sectors
15h 11 BYTEs reserved
---DOS 4+ ---
15h DWORD total number of sectors if word at 08h contains zero
19h 6 BYTEs ???
1Fh WORD number of cylinders
21h BYTE device type
22h WORD device attributes (removable or not, etc)
---DR-DOS 5+ ---
15h DWORD total number of sectors if word at 08h contains zero
19h 6 BYTEs reserved
---European MS-DOS 4.00---
15h DWORD total number of sectors if word at 08h contains zero
(however, this DOS does not actually implement >32M partitions)
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