Wiping Out Data

Matthew Flaschen matthew.flaschen at gatech.edu
Wed Mar 28 18:01:22 UTC 2007

Jeffrey F. Bloss wrote:
> I don't believe this is correct because dd doesn't work at that
> level. The command you suggested... 'dd if=/dev/random of=/dev/sdb'
> *should* fail with a "no media" error unless sdb is mounted.

I did not suggest that command.  I suggested shred , and said I had
heard the dd command /wasn't/ equivalent (can't confirm or deny).  I
tested the shred command before posting, and it definitely works without

> it should fail either way because you're not pointing dd at an
> accessible target partition.

That was just an oversight, but again I don't recommend dd.  I did
correctly specify partition when describing the shred.

> I'm not sure mkfs does anything significant as far as "bit wiping" goes
> either, although I'm not up on the mechanics of how it creates file
> systems.

It may zero everything (not sure), but the real data destruction was
already done by shred.  mkfs is just to recreate the filesystem after
shred-ding it.

Matthew Flaschen

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