www.delorie.com/djgpp/doc/rbinter/13.html   search  
Table 1395

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 (see #01646)
 16h	BYTE	media ID byte (see #01356)
 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 (see #01646)
 17h	BYTE	media ID byte (see #01356)
 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
SeeAlso: #01357,#01663,#01787 at AX=7302h,#04039 at INT E0/CL=71h

  webmaster   donations   bookstore     delorie software   privacy  
  Copyright 2000   by Ralf Brown     Updated Jul 2000