From mboxrd@z Thu Jan  1 00:00:00 1970
From: Greg Freemyer <greg.freemyer@gmail.com>
Subject: Re: Re-map disk sectors in userspace when rewriting after read errors
Date: Fri, 18 Sep 2009 14:02:10 -0400
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All,

I keep forgetting to ask, but the subject of this thread makes me
wonder if you guys are familiar with the hdparm features of
"--make-bad-sector", "--read-sector", and "--write-sector".

I don't know if any of those can be used to force a sector to be
remapped, but I could see a user space process like:

identify corrupt sector
hdparm --make-bad-sector   (to get it as corrupt as linux knows how).
calculate correct value
write new value to sector the normal way (hopefully the drive will
remap the bad sector)

hdparm --read-sector will do a low level read of the sector, including
the sector header and checksum as I understand it.  I'm not sure all
that gets back to userspace.

hdparm --write-sector will force a sector to be rewritten.  I don't
believe it is meant to ever cause a sector remap.  Of course you never
know what a disk drive is going to do for any given command.

Mark Lord is of course the expert on all things hdparm.

Greg