Re: ATA 4 KiB sector issues.

From: Tejun Heo
Date: Tue Mar 16 2010 - 02:22:35 EST


Hello, James.

On 03/16/2010 03:14 PM, James Bottomley wrote:
> So, it is true to say that picking a certain H/S geometry (which is
> entirely withing the gift of the partitioner) will align msdos label
> partitions, but will be don't care for all other labels: all other
> partition labels (like gpt) use block as offset and don't have any truck
> with the fictitious C/H/S stuff.

For any modern Linux and Windows, CHS simply doesn't matter. They
don't look at it at all.

> The big problem is that 99% of the x86 systems out there still use the
> ancient msdos label for their boot disks, so aligning H/S going forwards
> will give us a nice "just works" for x86 boxes.

What I don't get is that how picking up a custom geometry can make
things work when there is *no* reliable way to determine which
geometry was used during partitioning once the partitioning is
complete. Most BIOSs these days will simply report the geometry as
being 255/63 regardless of the geometry used during partitioning. So,
how can using a custom geometry give that nice "just works" for x86
boxes when nobody knows what geometry is in use?

Thanks.

--
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/