shredding files on a flash drive

[James Knott]

Kristian Erik Hermansen wrote:
> On Jan 25, 2008 7:34 AM, Lennart Sorensen <lsorense-1wCw9BSqJbv44Nm34jS7GywD8/FfD2ys at public.gmane.org> wrote:
>> On Thu, Jan 24, 2008 at 02:54:53PM -0800, Kristian Erik Hermansen wrote:
>>> That claim is apparently false, by numerous rebuttals to the Guttmann
>>> paper.  I will assume that the rebuttals are correct until someone can
>>> prove that.  Btw, I also have a question for you :-)
>>>
>>> Q: You open a hard disk drive case enclosure, remove the actuator and
>>> screws for the platters, and place two platters on your desk.  The
>>> data was intact and not overwritten when you pulled them from the
>>> caseing.  Can you recover the data on the platters?
>>> A: No.
>> My guess would be yes.  What reason do you have for saying it is no?
> 
> I challenge anyone to prove me wrong.  Go forth and study on your own
> disk if you like :-)  The reason is that once the platters are
> removed, they can never be aligned in the same way that they were
> manufactured.  Thus, an multi-platter hard disk data is unrecoverable,
> by any means...

Can you be so certain?  Many years ago, I used to maintain mini-computer 
systems, including disk drives.  There were many times I would repair a 
drive after a head crash and then do an alignment of the heads etc. 
When you do that, one thing that's obvious is that the data is recorded 
in clearly identifiable tracks, which you can locate by watching the 
recovered signal with an oscilloscope.  What's to stop someone from 
reassembling those platters in a similar drive and, with perhaps some 
effort, recovering that data?  It may be difficult, but I not 
impossible.  I know it's possible to align a drive to the data on a 
disk, because I've done it.  You might also want to talk to someone in 
the data recovery business.  IIRC, there was a presentation by one such 
person at a TLUG meeting a few years back.

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