[SPAM] [Hidden-tech] Recycling dead computers?

[Chris Woods]

Hey Chris,

That's true about Mac OS X secure erase although I have found that
when I get to end of life (this was on Tiger) the amount of memory I
had was insufficient to overwrite/buffer all the non-OS sectors (it
kept locking up in the middle; disk corruption can cause this too) so
I went to the hammer and nail method (the materials can be recycled
just as readily in that form) which takes only two or three well aimed
blows ;-). Also, 35 overwrites is time consuming (maybe 20+ hours)
which may or may not be decisive for some folks.

Keeping things simple for folks on the list, without a sector by
sector scan there is no telling what might be leftover on the disk
even when NSA approved techniques are used. I would expect them (NSA)
to scan each disk sector after employing Mac OS X secure erase to
verify the result. Otherwise, the possibility remains that there is
lingering data. For that reason, the nail through the platter method
provides reasonable piece of mind for an otherwise invisible process.
Alas, Windows folk have no secure erase feature but hammer and nail is
platform independent.


Chris



On Fri, May 23, 2008 at 10:57 AM, Chris Hoogendyk
<hoogendyk at bio.umass.edu> wrote:
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> Chris Woods wrote:
>>
>> One thing to keep in mind when recycling your old computer (or selling
>> it or giving it away): remove the hard disk. Re-formatting is
>> insufficient to protect your personal data (doubly true of Windows).
>> Take the hard disk out and physically destroy it (a hammer, safety
>> goggles, and a hard surface work well for this).
>>
>> See this study by Simson Garfinkel at MIT for more info:
>> http://tinyurl.com/2d8ysp
>
>
> Or, check out the links here:
>
> http://www.nsa.gov/snac/downloads_macOSX10_4Server.cfm?MenuID=scg10.3.1.1
>
> While those are good links in general for system security, the point in
> question here is the secure erasure of data. In MacOSX there is actually a
> command line utility for securely erasing data. It will do up to 35
> overwrites of the data with successive passes of 0's, 1's and random data.
> This meets the U.S. Department of Defense standard for the
> sanitation fro magnetic media. So, no harm hammering the drive if you are
> going to recycle the computer for raw materials; but, if you are going to
> donate it, then you can do a secure erasure of private data.
>
> Deeper down in the article linked to by Chris Woods is a statement that on
> modern drives a couple of overwrites should be sufficient. The point is that
> you can't just delete the data, because on most operating systems that just
> unlinks the data blocks and puts them in free space. I actually had an
> experience around 1992 where a software company I worked for had some people
> come in to demo a product they were developing. We had top of the line
> equipment, so they were encouraged to copy their code into our computer and
> demo it there. They carefully "removed" all their code and data after the
> demo. As soon as they left, several programmers descended on the computer
> and went about scouring the blocks of free space and reassembling their
> code. Needless to say, they were never called back to arrange any sort of
> business deal. (As I pass that story along, I want to say that the company
> was not Specular. A number of people will be aware that I worked for for
> Specular for several years. They were one of the most ethical companies I
> ever worked for. I'm sure they would not have done that sort of thing. Nor
> would they have needed to. Their programmers could spin magic out of thin
> air.)
>
>
>
> ---------------
>
> Chris Hoogendyk
>
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>  O__  ---- Systems Administrator
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> <hoogendyk at bio.umass.edu>
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