Format of DR Multiuser DOS Disk Parameter Block (DPB):
Offset	Size	Description	)
 00h	BYTE	drive number (00h = A:)
 01h	BYTE	relative unit number
 02h	WORD	sector size in bytes
 04h	BYTE	sectors per cluster - 1
 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	number of clusterse on disk
 0Fh	BYTE	number of sectors per FAT
 10h	WORD	sector number of first directory sector
 12h  4 BYTEs	reserved
 16h	BYTE	media ID byte (see #01356)
 17h	BYTE	00h if disk accessed, FFh if not
 18h  6 BYTEs	reserved
 1Eh	WORD	number of free clusters on drive
Note:	this structure is a subset of the MS-DOS 3.x Drive Parameter Block
SeeAlso: #04038,#01357 at INT 21/AH=1Fh,#01395 at INT 21/AH=32h