Re: I'd like to fix read failure issue on Mac OS X

On 18/12/14 22:54, Kimio Miyamura wrote:
> If the sector
> reported by smartctl is because of bug in HDD's bug, is there anything I
> can do to suppress this error message?
> Or should I ignore this error message?

My guess is that the error sector is "real", but it's beyond the max
user-addressable-LBA, so it is not accessible by the OS.  Maybe it's a
sector used by the drive for internal management (e.g. record keeping),
or even is just unaddressable (to keep max LBA consistent between
makes/models), or it may be a "spare" sector which is usually used when
a sector is reallocated (but has gone bad itself before it's been used!).

> I can do zero-disk for entire my hdd if it required.  Can this fix the
> issue?

As this sector isn't user-addressable, then a normal zero-out won't work
I think.

There are two things you could try - both will use hdparm, don't know if
that's available under OSX, but if it isn't, you can use use the grml
boot disk which you already have instead.

First try using hdparm --write-sector on the sector which the drive is
reporting as in-error.

If the drive doesn't allow that, then an ATA "SECURITY ERASE UNIT", or
more likely (if supported by your drive) an "ENHANCED SECURITY ERASE
UNIT" command might cause that sector to be overwritten (along with all
the other sectors on the drive of course).

Whether either of these actually overwrites the sector in question will
depend on the implementation of the drive firmware...

https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase

... substitute --security-erase-enhanced in "step 3" if hdparm -I shows
it's supported, as I think this will have the greatest chance of
overwritting "everything".

Make sure you erase the right drive!  :-)

Tim.


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