DoN. Nichols wrote:
On 2011-05-25, Ignoramus23924 wrote:
I have a little industrial demagnetizer from a grinding shop. Can this
thing erase contents of hard drives securely? Or the magnetic field is
not string enough? I have a pile of old HDs awaiting destruction.

Likely not strong enough to *securely* erase the data. It might
weaken things enough so the computer would have difficulty reading the
disk, but for someone taking serious data-recovery measures, they would
have no trouble.

Note that the tape degausser for 9-track data tapes which I have
has poles above and below the tape (so the field goes right through the
tape), and the tape reel is spun between the poles while the platform
slowly moves out so the whole of the tape passes between the poles.

And -- there is a series capacitor in the tape degausser
connected to resonate with the inductance of the coils (at 60 Hz, of
course) to maximize the field (with a warning of extreme voltages within
the case) -- so unless your industrial demagnetizer is constructed on
similar lines, the odds are that it will not do very well at all.

And -- I'm not sure about the coercivity of the media in the
drives -- it may take a stronger field than the old mag tapes took.

THe alternative is my press, which is more of a PITA.

Give the kid(s) some torx screwdrivers, and a challenge to strip
each drive as far down as they can -- saving the metric screws, and the
bearings, and especially the head servo magnets. Most kids love to take
things apart, especially male kids.

Or -- take them down to your favorite outdoor shooting range,
and see how many stacked up drives you can send various calibers
through. If you get through all of them in a single shot, you have
securely erased them *very* quickly.

Or -- if you have always wanted to play with thermite, put each
drive under a pile of thermite, and light it off. :-)

Enjoy,
DoN.



DON! What have you been hiding???



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Richard Lamb
http://www.home.earthlink.net/~cavelamb
http://www.home.earthlink.net/~sv_temptress