

How To Erase Old Hard Drives Without A Drill Bit - sarvesh
http://www.npr.org/templates/story/story.php?storyId=101042323

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sarvesh
The reason I posted this is that regular users shouldn't be going through such
pain to erase their drives. One solution I can think of is a unix live boot CD
that specifically only does this (dd if=/dev/zero of=/dev/) to the drive they
want to erase. Won't that work or am I missing something?

~~~
jws
It depends on the consequences of data exposure. Writing zeroes works, except
that any bad blocks that have been mapped out will still contain their last
data. A sufficiently motivated "bad person" could read those, possibly by
performing some "unmark bad block" operation on the drive.

Bit zones on a disk are analog things, think of writing zeroes as laying a
blank piece of paper over a written secret message. You may still be able to
read the secret message. In the olden days it was possible to use specialized
tiny devices to read the analog the disk's surface and work out the previous
data. (This is the origin of the "erase (7|49) times" rules.)

I rather doubt that modern drives can be read this way after a wipe. There is
a dollar reward out for any data retrieval service that can retrieve data from
a wiped drive that is, as yet, unclaimed. I think the PR win would inspire
that crowd to demonstrate the capability if they had it. That leaves wealthy
nations as possible readers.

Given the minimal value of an old hard drive, I give them a few chops with a
splitting maul if I have a couple, when getting rid of many of them I take
them to an ewaste handler and pay him $10 to throw them in the shredder while
I watch. That way they get recycled better.

