[clug] Re: More (almost free) stuff. - 3.5" WD 200GB IDE - $10

[Daniel Pittman]

Ian <darkstarsword at gmail.com> writes:

> I have heard a technique described to recover data from an overwritten
> drive - no idea whether it would actually work or not though.
>
> The idea is that you would hook up some sort of digital oscilloscope
> directly to the read head to be able to observe the magnetic pattern
> on the disk as the head reads it and compare that to what the drive
> tells you is in that location.

[...]

> So, anyone have any idea whether that's even plausible or not?

A more extreme version uses a scanning electron microscope to scan the
disk surface, and has, in an unclassified demonstration, recovered data
overwritten to US military standards.  (7 wipes, random, etc.)

This can also go back in time quite a few overwrites of each sector, and
do all sorts of data recovery that was not thought practical until
tried.

So, yes, that is practical[1], and is probably vastly less effective
than some of the techniques that are unknown to the general public.

See also http://blocksandfiles.com/article/5056 which details briefly
the data recovery success on a disk that was recovered from the failed
shuttle mission.

Regards,
        Daniel

Footnotes: 
[1]  ...as I understand things, and I am not an expert in this area.