[GRLUG] Data wiping / recovery / paranoia

[john-thomas richards]

On Fri, Sep 15, 2006 at 03:35:17PM +0000, Jorge La wrote:
> ^yeah, "shred"
> 
> so woun't that be fool proof against recovery? because the whole hdd would
> be filled w/ 0s
[snip]

My understanding of this issue is that shred writes the zeroes many,
many times.  I recall reading an article that explained that simply
writing over data once is not sufficient because not all the bits of
magnetic material get rearranged.  It is like writing a word on a
sheet of paper and then erasing it lightly and writing another word
over it.  There is often enough of the original word to see what it
was.  In the case of a hard drive, writing the same data over and over
will eventually rearrange all the bits and thus truly wipe the old data
clean.
-- 
john-thomas
------
Space isn't remote at all. It's only an hour's drive away if your car
could go straight upwards.
Fred Hoyle, Astronomer, mathematician, writer (1915- )