> It seems the partition always start on LBA 63. For many modern harddrives
> that is the max number of heads. And for a drive with 63 heads it will
> be Cylinder 0 Head 1 Sector 1 (since sectors start at 1, not 0).
> On your flash drive with 32 fake heads LBA 63 becomes C/H/S 0/1/32.
Excellent! That explains the starting CHS values in the MBR partition
tables, but we still need to explain the ending CHS values. Here are the
MBR partition tables of two more usb flash drives formatted on Windows
machines:
Disk: sd0 geometry: 797/128/10 [1020160 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
------------------------------------------------------------------------
0: 0B 0 6 4 - 796 127 9 [ 63: 1020096 ] Win95 FAT-32
1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
Disk: sd0 geometry: 3935/64/32 [8060926 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
------------------------------------------------------------------------
0: 0B 0 1 32 - 3935 63 17 [ 63: 8060850 ] Win95 FAT-32
1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
I am most confused by the ending cylinder of this last table. There are
3935 cylinders numbered 0 through 3934, so cylinder 3935 does not exist.
In fact, the openbsd fdisk utility will not allow me to enter 3935 at this
point in the partition table. So, why do Windows machines and Macintoshes
both put cylinder 3935 in the MBR partition table?
