[GLLUG] Off Topic Hard Drive Question

[Ben Pfaff]

Jeremy Bowers <jerf at jerf.org> writes:

> Mark Tarquini wrote:
>> Question:
>> I have a laptop which I have determined has a hard drive with bad
>> clusters on it.  Can I partition around the bad clusters and only use
>> the partitions that do not have bad clusters?
>
> Modern hard drives have error correction built into them,
> automatically and silently mapping bad sectors to good ones. Modern
> hard drives all reserve some sectors for just such a use when they are
> created.

There are two sides to automatic remapping: read and write.  A
bad sector will not be remapped on read, because the drive would
then have to return corrupted data.  Instead, it will return an
error.  On the other hand, bad sectors *will* be remapped on
write, because the drive knows what the sector should have in it
in that case.  Therefore, sometimes the solution to a bad sector
is to write to it.  (More often, it means the drive is dying and
should be replaced soon.)
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