Re: Disk geometry from /sys

Hi Seewer,

On Mon, Apr 14, 2008 at 2:57 PM, Seewer Philippe <philippe.seewer@xxxxxx> wrote:

As you've problably seen from the other answers, disk geometry is (except
for a few older devices) unneeded inside the Linux kernel.

Yes but I'm doing userspace stuff and that's the reason I was asking for the
sysfs thing.

I'd say thats the
reason why there's no sysfs export and I'd further guess disk geometry is an
artifact most would like to get rid of (or pushed into userspace).


Well, I looked at sfdisk(8) and parted(8) source code and they all need the
geometry description. If I understood correctly the reason why is that it
'prefers' to align partition sizes/starts on a cylinder boundary because some
bootloaders probably use CHS addressing, but I'm really not sure.

Anyway, if you really need it, try the patch below. Should apply cleanly to
version 2.6.23.1 and gives you a geometry/ directory for each block device
providing the getgeo function. It adds a setgeo counterpart for some
subsystems as well, allowing 'echo something > ...' so please be careful.


Thanks but I probably won't use it. Using sfdisk, for example, is a
more portable
way to get the geometry from a script.

--
Francis
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