[kwlug-disc] Media errors on a USB disk

[Eric Gerlach]

On Sun, Oct 24, 2010 at 10:25 AM, Bob Jonkman <bjonkman at sobac.com> wrote:
> This is why I wonder about Spinrite.  While it seems to be an awesome
> program, it DOES pay attention to partition tables and partitions, so it's
> not just checking the raw sectors on the disk. But it checks an ext3
> partition just as readily as an NTFS partition.

I don't know why it allows that option either... I've only ever run it
on entire disks, and don't know why you would want otherwise.  It
definitely operates on the block level, though.

> FWIW, I've never managed to recover a damaged drive with Spinrite.  Either
> the drives I checked aren't badly enough damaged, so Spinrite indicates
> they're good, or the drive is so badly damaged that even Spinrite can't read
> it.  I've had a drive that banged its heads against the backstop, run
> Spinrite on it for 30 days continuously, and while Spinrite marked most of
> the drive as "Bad" it didn't recover a thing.

What's interesting is that because of the way SpinRite does things at
Level 4 (read, invert, write, read, invert, write, read), it will
sometimes cause the drive to catch sectors that are bad, but the drive
didn't realise it.  In the story I submitted to Security Now (which
got read on the air twice), when SpinRite ran it didn't do any
"DynaStat" recovery.  But the drive worked afterwards.  So you don't
always *see* it working.  Sometimes it just helps the drive out, and
since the drive doesn't say "Thank You," it can't tell you it did
anything.

I will agree though, that many of the times a user comes to me and
says "I think my HD is bad," the drive is too far gone for anything.

Cheers,

Eric