[clug] Secure Erase of disks/drives

Hugh Fisher hugh.fisher at anu.edu.au
Wed May 9 03:57:29 GMT 2007

I just had to erase the hard disk of a Macintosh due for
recyling, so thought I'd look into the options provided
by Apple.

There are four levels of security: the 'zap the top level
directory' non-secure way or writing zeroes over the
entire disk 1, 7, or 35 times. Apple describe the last
two as 'highly secure' and 'highly effective security
against data recovery' and probably 7 or 35 passes are
required by some US government standard.

7 passes was going to take over 8 hours, and 35 passes
the best part of 2 days, so I opted for the 1 pass
which just finished in a little over an hour. That's
for a 60G disk, not huge by todays standards.

(Yeah, yeah, open source Linux software will have better
performance than tools written by the capitalist minions
of Apple, but it's not going to *that* much faster.)

Hitting disks with a hammer looks much more attractive
if you're impatient!


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