RE: [Nolug] Why geeks don't wipe hard drives...

Hi Ron.

All the schemes are digital, I believe, with just 2 values. The differences
are in the self-clocking (read: encoding scheme) and density. So I'm
thinking that what I said does apply to all of the formats.

Disk vs Tape: Different heads of course, but still basically the same
thing. A field across a gap magnetizes the media. The resulting electrical
signals look pretty much the same I would think.

Exception: Vertical recording I'm not familiar with at all.

Regards,

John

    John Souvestre - New Orleans LA - (504) 454-0899

-----Original Message-----
From: owner-nolug@stoney.kellynet.org
[mailto:owner-nolug@stoney.kellynet.org] On Behalf Of Ron Johnson
Sent: Thursday, March 24, 2011 5:19 PM
To: nolug@nolug.org
Subject: Re: [Nolug] Why geeks don't wipe hard drives...

On 03/24/2011 04:25 PM, John Souvestre wrote:
> Hi Ron.
>
> >> If you are planning on selling them or giving them away, then a 1
pass
> >> wipe isn't really protecting your data from anything...you're gonna
> >> need to spend waay more than 3 hours to do a "secure" wipe ;)
> >
> > And that's a myth.
> > http://www.cs.auckland.ac.nz/~pgut001/pubs/secure_del.html#Epilogue
> >
> > Read the further epilogue: '"A good scrubbing with random data will
do
> > as well as can be expected". This was true in 1996, and is still
> true now.'
> >
> > So, a single pass writing random data is all that's necessary.
>
> The NSA would like you to believe that. :)
>

But there is No Such Agency...

> I've played with magnetic recording a bit in the past, mainly with mag
tape.
> I could see the effects of a previous image on the current image. I
> don't understand why this wouldn't be true for disk, also.
>

Different recording methods and densities. Especially if it's an ancient
tape format.

--
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and happiness of a people whose manners are universally corrupt."
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