Wiping Out Data

[Jeffrey F. Bloss]

Matthew Flaschen wrote:

> 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

Indeed. I misread or "mis-remembered" what you had written. My humble
appologies...

> > 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.

I don't think mkfs writes any real "data" at all. In fact I'd bet that
if you simply delete/create ext2/3 partitions you run a chance of
having every bit of the old partition's data in place after the "new"
partitions has been created. Assuming all the geometry is perfect of
course. A single block error and all bets are off. ;)

-- 
     _?_      Outside of a dog, a book is a man's best friend.
    (o o)         Inside of a dog, it's too dark to read.
-oOO-(_)--OOo------------------------------[ Groucho Marx ]---
                    http://wrench.homelinux.net/~jeff/

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