linux-kernel - Re: Disk geometry from /sys

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Date:	Thu, 17 Apr 2008 16:09:01 +0200
From:	"Francis Moreau" <francis.moro@...il.com>
To:	"Seewer Philippe" <philippe.seewer@....ch>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Disk geometry from /sys

Hello Seewer,

On Wed, Apr 16, 2008 at 9:49 AM, Seewer Philippe <philippe.seewer@....ch> wrote:
>
>  Correct. Though be really careful which geometry you are requesting:
>
>  root@...al:/# sfdisk -g /dev/sda
>  /dev/sda: 7296 cylinders, 255 heads, 63 sectors/track
>  root@...al:/# sfdisk -G /dev/sda
>  /dev/sda: 116280 cylinders, 16 heads, 63 sectors/track
>
>  The first one is the kernels idea of a disks geometry which is probably as
> often correct as it's just plain wrong,

Sorry but I don't understand, what do you mean ?

>  versus the second one which tries to
> guess a disks geometry by looking at the current partition table. Which
> might be just as wrong since its only necessary for bios and/or bootloader.

But what happens if you want to guess the geometry of a disk with no
partition table ? You need to trust the kernel guess but from what I understood
it's just wrong.

thanks
-- 
Francis
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