Format of Extended BIOS Parameter Block:
Offset	Size	Description	)
 00h 25 BYTEs	same as standard DOS 4-6 BPB (see #01663)
 19h	DWORD	sectors per FAT if WORD at 0Bh is 0000h
 1Dh	WORD	extended flags
		bit 7: do not mirror active FAT to inactive FATs
		bits 6-4: reserved (0)
		bits 3-0: the 0-based FAT number of the active FAT
		    (if mirroring disabled)
 1Fh	WORD	file system version (high byte=major, low byte=minor)
		0000h = Win95-OSR2
 21h	DWORD	starting cluster number of root directory
 25h	WORD	file system information sector number (see also #01788)
		FFFFh if none
 27h	WORD	sector number of backup boot sector (FFFFh if none)
 29h  6 WORDs	reserved
SeeAlso: #01560,#01787