secure data erasing

["Wolfgang S. Rupprecht" at wsrcc.com]

alvin at Mail.Linux-Consulting.com (Alvin Oga) writes:
> - sledge hammer will be an option on a couple of the disks
>   but not the other disks .. ( it'd be a "waste of disk" )

If you find a degausser strong enough to erase the disk data then you
will also be erasing the tracking track's information, the spares /
bad-block data, and perhaps the drive's second-stage firmware.  Save
yourself the trouble and hit it with the big hammer.  The result is
the same and you save yourself a lot of hassle.

Personally I just fill my old drives with zeros using dd(1) to write
to the raw device from /dev/zero.  Anyone that has the technology to
read once-erased data is also going to have the technology to read
data from the computer using non-contact means, or do some B&E and
just duplicate the disks still in the computer when nobody is around.

-wolfgang