Re: Problem with larger IDE drive

Alexander Stavitsky (stalex@physlab.sci.ccny.cuny.edu)
Thu, 25 Mar 1999 03:30:10 -0500


On Wed, Mar 24, 1999 at 11:20:31PM -0800, H.J. Lu wrote:
> Hi,
>
> I have a question on large IDE drive. For IDE HD > 8.4GB, # of
> cyliners is > 1024. The kernel always report
>
> CHS=1024/255/63

I am not 100% sure, but I think this CHS comes from bios and
bioses tend to refuse properly autodetect the drive that's
larger 8.4GB. I usually have to set up the proper geometry in bios cmos setup.
If you only use linux on that drive it doesn't really matter,
but if you use any M$ -- most of them have trouble with more
than 1024 cylinders.
Make sure that no partition that accessible to them runs over 1024 cyls.
I had seen them trash other partitions when trying to do that.

>
> That means I cannot use anything above 8.4GB unless I play with
> fdisk. However, the kernel reports the correct size of the HD.
> That is idedisk_capacity () knows the correct geometry. Is there
> a way for fdisk to get the correct HD geometry from the kernel
> without breaking things? Since I can use fdisk to set the
> HD geometry to use the whole HD, I don't see why the kernel
> cannot do it for me.
>
> Thanks.
>
>
> - --
> H.J. Lu (hjl@gnu.org)
>
> Please read the FAQ at http://www.tux.org/lkml/
>
> ------------------------------

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