off topic - disk crash

[Clifton Royston]

> Date: Wed, 10 Mar 2004 18:36:52 +0100 (CET)
> From: "C. Kukulies" <kuku at www.kukulies.org>
> Subject: off topic - disk crash
> To: hackers at freebsd.org
> Message-ID: <200403101736.i2AHaqIF029948 at www.kukulies.org>
> 
> Today an important (no backup of course) 46 GB IBM Deskstar
> IDE disk crashed. It has a FreeBSD 4.8 on it with important data and programs.
> Yes, shame on me that I didn't care about doing backups on it but it
> has happened.

  This specific line of drives is infamous for a failure rate that's at
least a full order of magnitude above the industry average for ATA
drives.  Google a bit for it.  
 
  I just spent a weekend replacing that exact model of drive and trying
to recover data for our babysitter's (WinMe) computer, without success.

> I evend tend to expend the bucks to get it recovered but a little
> prediagnosis I would not to be left untried.
> 
> The disk boots into FreeBSD but already at power on time the disk does
> seek retries or some recalibration noise.
> 
> The question is what else can I do to recover the data.
> Put it in the icebox? 

  Yes, this might actually help, provided the read head is not yet too
badly damaged or stuck to the platter.  One of the several problems
with the drive seems to relate to overheating.

> Turn the computer upside down?

  I'd remove the drive from its mounting and just hook it up loosely
cabled into an open system while you try to recover.

  There's supposed to be some firmware update you can get from IBM to
update the drive firmware, which can help reduce the chance of these
errors and might help recover the data.  If you can find the firmware
update from IBM, boot a system in DOS with the drive hooked up, and run
the flash utility, that might help with the following steps.

> Any ideas would be welcome.
> 
> I thought of getting a second identical disk to exchange electronics
> only but since it partially functions it looks more like surface corruption,
> doesn't it?

  From what I've read online part of the failure mode may have to do
with stray particles of crud inside the platter area from a bad
manufacturing process (or coming loose from the drive surface over
time) attaching to the read head and resulting in a head crash.  The
other problem was that the drive sometimes didn't park the head safely
on powerdown.  It's very unlikely to be an electronics problem.  It all
depends how bad the crash is and what the current condition of the head
and surface is whether you will get anything back off again.  In my
case I couldn't get past 5% into the drive using the disk utilities I
had, but working in FreeBSD with its known data structures you might be
able to do better.

  You've been given good-sounding advice about what to try on the
software side by a previous poster.  I recommend following the
suggestion given by that poster.

  On the hardware side, before you start trying to copy the data off,
first try this firmware update if you can find it (Google for it) and
then make sure the drive is extremely well cooled while you're trying
to copy the data off.  Either prechill it or have it in open air with a
fan blowing on it, or both.  If you can't get it to start reading at
all and can't get anything off, the head may be stuck to the disk. 
ONLY if you can't seem to get anywhere at all with it, in that case
(sensitive types may want to shield their eyes at this point) you could
try picking up the drive and banging it on the table once or twice
only.  Sometimes this will free the head on a crashed hard drive and
let you read it long enough to recover the contents, though it tends to
rapidly destroy working drives.  I have done this very very rarely in
my career, but occasionally it's let me resuscitate a drive long enough
to save some data.

  Good luck on getting your data back; the lady I was helping didn't
have any.

  -- Clifton

-- 
          Clifton Royston  --  cliftonr at tikitechnologies.com 
         Tiki Technologies Lead Programmer/Software Architect
Did you ever fly a kite in bed?  Did you ever walk with ten cats on your head?
  Did you ever milk this kind of cow?  Well we can do it.  We know how.
If you never did, you should.  These things are fun, and fun is good.
                                                                 -- Dr. Seuss