Darren New wrote:

> It depends how you erased the drive. If you just formatted it, no, the 
> data's all still there. If you actually overwrote it, it takes special 
> electronics to retrieve it if you can at all.

I'm told if you take the drive apart, you can take advantage of slight 
tracking errors in the read/write heads that allows traces of old 
signals to remain present at the margins of each track. However, this is 
NOT a cheap operations AFAIK. (!!) It requires clean-room conditions, 
sophisticated magnetic scanning microscopes, detailed knowledge of HD 
construction, etc.

> If you're the DoD, and large numbers of people die when a foreign 
> government spends several millions of dollars to recover the data from 
> the disk, yes, 21 passes is probably good. That, or scrubbing the drive 
> with a belt sander or wire brush and then soaking it in acid until it 
> dissolves.

...or just incinerate the platters? (Heat tends to disrupt magnetic 
domains rather efficiently - as does the platters being reduced to 
molten glass and deformed beyond recognition!)

Anyway, hypothetically supposing somebody magically recovered every 
single file from these drives, they would get... the names of the drugs 
we were working on 5 years ago, and possibly some analytical results 
data. Which won't mean a damned thing, because they won't know what 
"sample 39" actually *is*.

It's more the fact that the drives had licenced software on them that 
other people shouldn't have...

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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