Re: ATA 4 KiB sector issues.

From: Nikanth Karthikesan
Date: Thu Mar 11 2010 - 09:59:35 EST


On Thursday 11 March 2010 19:58:11 Theodore Tso wrote:
> On Mar 11, 2010, at 8:57 AM, Nikanth Karthikesan wrote:
> > I guess, what he meant was, to keep filesystem blocks aligned, even if
> > the partition is not. Say if the partition is mis-aligned by 512-bytes,
> > let the filesystem waste 4k-512bytes and keep it's blocks aligned. But it
> > might be a case of over-engineering, possibly requiring disk format
> > change.
>
> Ah, yes, I agree with you; that's probably what he meant.
>
> Sure, that's theoretically possible, but it would mean changing every
> single filesystem, and it would require a file system format change --- or
> at least a file system format extension.
>
> It would seem to be way easier to simply fix the partitioning tools to do
> the right thing, though.
>

Yes. May be, just a simple but transparent device-mapper like mapping on top
of the mis-aligned partition, to do the alignment. Then the file-system code
need not change much.

But Linux already has device-mapper and Linux will not be affected with mis-
aligned partitions, when we use LVM.

But the actual problem here is that partitioning tools might create partitions
that wont allow other operating-systems to boot. So it might be enough, if the
partitioning tools just create partitions with (mis-)alignment requirement for
Windows.

Thanks
Nikanth
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