[Gllug] Securely disposing of old hard drives

[Frank Scott]

On Tue, Aug 21, 2007 at 09:00:15PM +0100, John Hearns wrote:
> 
> I would say an oven would be better - heat the platters to above the 
> Curie temperature and any magnetic
> domains in the material are gone.
> http://en.wikipedia.org/wiki/Curie_point

Well most of the many drives I've taken apart have aluminium alloy platters with some sort ferromagnetic coating. Since aluminium alloys melt at below about 660C and
the wikipedia article quotes Curie points for colbalt at 1388K and iron
at 1043K, the platters are going to melt well before reaching the Curie
point.

I have tried heating platters to destroy them. I dissembled the drive
and heated the aluminium platter on the ring of an electric stove. The
multi-hued platter sitting on my desk has a very interesting flow
pattern where the alloy has melted and resolidified. I doubt that any
domestic oven will get hot enough to effect any intact drive ( I don't
have a pottery kiln).

People who really care about sanitizing discs, physically destroy them
(by pulverisation usually) not because the software methods don't work,
but because the audit trail is a lot easier to a pile of dust than it is
to verify a disc has really been wiped clean.

Frank  
-- 
    .^.     .''`. 
    /V\    : ;`  :   Frank Scott  Sutton, London
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