[ale] really really deleting files....

[James P. Kinney III]

On Tue, 2003-06-24 at 15:52, Keith R. Watson wrote:
> At 01:34 PM 6/24/2003 -0400, you wrote:
> >On Tue, 24 Jun 2003, Keith R. Watson wrote:
> >
> ><<snip>>
> > > Recoverable - 1. Your data can't be reassembled and viewed by an 
> > un-authorized
> > >                   party regardless of the level of effort required (The NSA
> > >                   couldn't do it with unlimited funds)
> > >
> >
> >More curious than anything else, but to beat Recoverable 1, would drilling
> >a small hole in the case and filling the cavity with HF solution (the
> >stuff often used to etch glass) work? Plug the hole with a polyethylene
> >plug, and _anybody_ who opened the case to get at the platters would get a
> >relatively nasty surprise.
> 
> I assume your talking about hydrofluoric acid. Certainly an interesting 
> solution (pardon the pun). Not all substances are soluble in hydrofluoric 
> acid. If the ferromagnetic coating on the platters is susceptible then it 
> might do the trick. The case must be capable of containing the acid. Not to 
> mention that the hard drive becomes a serious environmental contaminant at 
> that point.
> 
> keith
> 
> 
A better (ahem) solution might be to use HCl. The platter surface is
Ferrous Oxide known to most normal humans as rust. Hydrochloric acid is
a very effective rust remover. As the casing metal is usually aluminum,
the acid will work itself to death converting the aluminum to AlCl, a
harmless salt.

I don't think it would be possible to reassemble the dissolved FeO2 and
recover any magnetic domains.

But the issue as posed is more "How to securely recycle a hard drive".

My (untested) solution (using no caustic chemicals):

For i in 0 1 2 3 4 5 6 7 8 9 do
startblock=$(9-$i)
dd if=/dev/random of=<ramdisk>/block bs=1048576 count=1
dd if=<ramdisk>/block of=/dev/hdx obs=1 ibs=3 seek=$i skip=$startblock
done

This would take a while with a 200G hard drive :)
> 
> -------------
> 
> Keith R. Watson                        GTRI/ITD
> Systems Support Specialist III         Georgia Tech Research Institute
> keith.watson at gtri.gatech.edu           Atlanta, GA  30332-0816
> 404-894-0836
> 
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-- 
James P. Kinney III          \Changing the mobile computing world/
CEO & Director of Engineering \          one Linux user         /
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GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics) <jkinney at localnetsolutions.com>
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