BPB - BIOS Parameter Block

     Offset Size	    Description

	00   word	sector size in bytes
	02   byte	sectors per cluster (allocation unit size)
	03   word	number of reserved sectors
	05   byte	number of FATs on disk
	06   word	number of root directory entries (directory size)
	08   word	number of total sectors; if partition > 32Mb then set
			to zero and dword at 15h contains the actual count
	0A   byte	media descriptor byte  (see MEDIA DESCRIPTOR)
	0B   word	sectors per FAT

	Additional/different fields for DOS 3.0+
	0D   word	sectors per track
	0F   word	number of heads
	11   word	number of hidden sectors
	15 11bytes	reserved

	Additional/different fields for DOS 4.0+
	15   dword	number of total sectors if offset 8 is zero
	19  6bytes	reserved
	1F   word	number of cylinders
	21   byte	device type
	22   word	device attributes

	- located in the boot sector at offset 0Bh

	- see	BOOT SECTOR