Stephen C. Tweedie (sct@redhat.com) writes:
> Hi,
>
> On Thu, Apr 13, 2000 at 09:18:09AM -0500, Ed Carp wrote:
> >
> > > Huh? Modern disks do this for you anyway. It is counterproductive
> > > for the kernel to try to help, because if the kernel remaps what appears
> > > to be a bad block, then you're just duplicating effort. The next time
> > > the kernel tries to write to that "bad" block, the disk will have
> > > remapped it on its own.
> >
> > Most modern disks do this for you *transparently* - the driver doesn't even
> > see the error, so this does't really apply. If the kernel sees an error, it's
> > a real error, as opposed to one that has been remapped.
>
> Not quite. If you get a read error, the drive will do the remapping
> for you such that future writes to the same sector will be mapped
> elsewhere on disk. However, that transparent remapping cannot, by
> itself, restore the contents of the lost sector. The kernel will
> still see the read error --- it's only future contents of the same
> logical sector which will be remapped.
"Real", not "read". What you are saying is true only for reads - for writes, the write is transparently redirected.
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This archive was generated by hypermail 2b29 : Sat Apr 15 2000 - 21:00:23 EST