Disk geometry from /sys

["Francis Moreau" <francis.moro@gmail.com>]

Hi,

I'm trying to know the geometry of my hard disk from a bash script
and that's the reason I'm looking in /sys. The reason is that I'd like
to figure out the size of a cylinder without doing a
ioctl(bdev, HDIO_GETGEO, &geo)

Unfortunately I can't find anything useful and this is certainly a sign
that I'm doing something wrong.

Or maybe can I simply assume from my script that the geometry
is always heads=255 and the number of sectors per track is 63 for all
disks.

Looking at parted(8) source code, I  can find this:

/* The GETGEO ioctl is no longer useful (as of linux 2.6.x).  We could
 * still use it in 2.4.x, but this is contentious.  Perhaps we should
 * move to EDD. */

Could anybody give me some advices ?
-- 
Francis