On Mon, 14 Mar 2005 11:54:32 -0800, Todd Walton <[EMAIL PROTECTED]> wrote:
> On Mon, 14 Mar 2005 10:47:11 -0800, Stewart Stremler <[EMAIL PROTECTED]>
> wrote:
> > nohup sudo dd if=/dev/random of=/dev/hda & exit
> >
> > -Stewart "Not tried it. Ought to try it. Surely it'll work?" Stremler
>
> Depends on the filesystem you're using, but you'd probably want to
> overwrite the hard drive several times. I was reading a magazine
> article in 2000 that said forensics people can read data from a hard
> drive that's been overwritten up to 9 times. Surely that number has
> gone up since then. (The 9, not the 2000.)
>
Much of this "read after N overwrites" stuff becomes obsolete as the
density of data on the disk increases. At the perhaps only slightly
obsolete density of 40GB per platter, the actual reading of data from
the disk heads involves a great deal of digital signal processing to
winnow out the noise from the adjacent tracks. None of this "let's
read slightly off-track and see what wasn't quite written over".
carl
--
carl lowenstein marine physical lab u.c. san diego
[EMAIL PROTECTED]
--
[email protected]
http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
