Fixing a crashed disk

[Alan Cox]

> Beg to differ.  Remember, drives have reserved storage to remap bad sectors
> *before* you ever see a bad sector at the interface.  So, by the time you
> think you're seeing only 8 bad sectors, you've actually burned through
> the reserved sectors--many more have failed than you realize.

Completely wrong.

You see a bad sector on some devices after a sudden power fail because
the sector was partially written when the power failed. It's not bad in
any permanent sense it's just got incomplete data on it so cannot be read
back properly until rewritten.

Similarly btw any case where a sector reports as "bad" on a read does not
mean you've used up all the spare sectors or anything of the sort, it
means you've got a sector which failed to read.

Some drives also (quite validly) report the number of sectors that were
failed during the production of the device, which completely throws most
of the rather weak drive reporting stuff software.

What really matters is whether the drive itself thinks on its smart test
whether it is likely to be failing not some joke heuristic.

Bad sectors *can* be a sign of problems - be they drive failure,
mechanical mounting problems (eg vibration), poor cooling, poor power and
so on but not in this case. The warnings also often look different - you
see a continuing to rise number of bad sectors.

Alan