I'd recommend DBAN as well. I've recovered plenty of data from a drive that has been zeroed with /dev/zero before. --Adam On 1/20/2012 9:08 PM, Brian Wall wrote: > On Fri, Jan 20, 2012 at 2:17 PM, Mike Miller<mbmiller+l at gmail.com> wrote: > >> But seriously -- regarding /dev/zero -- does anyone think there are any >> *real* worries about data recovery after you've filled the drive with zeros? > Yes. I once used a tool (Ontrack maybe?) that found bits of file > structures after wiping with /dev/zero. Ever since then, I rely on no > less than a 3 pass DBAN wipe. > >> I know if I was working on a secret project at Microsoft, I wouldn't fill >> my old drive with zeros and then hand it to developers at Apple or Oracle, >> but if we're talking about giving a personal hard drive to someone who just >> wants to use it in their personal computer, isn't use of /dev/zero plenty? > I trust no one, but I'm weird that way. > >> Jeremy pointed out that /dev/urandom would use random bits. I would think >> that /dev/urandom would be a better choice than /dev/zero. Is there any >> reason to prefer /dev/zero? In other words, isn't this a really good >> answer: >> dd if=/dev/urandom of=/dev/<drive> >> Is it really even necessary to do that twice? > In theory, alternating bit patterns mask magnetic signatures better > than a single stream of 0s. Multiple passes increase the masking > effect and make software based recovery impossible. If I don't have > DBAN handy, I'll usually do two passes of urandom and one pass of > zeros. It makes me feel better for some reason. Irrational paranoia > is fun sometimes. > >> To properly mess up that drive, can I just do this?: >> dd if=/dev/urandom of=/dev/sdb > Can and should. As others have stated, this whacks the whole > partition table, boot sector, and of course all areas of the drive > with data. > > Brian > _______________________________________________ > TCLUG Mailing List - Minneapolis/St. Paul, Minnesota > tclug-list at mn-linux.org > http://mailman.mn-linux.org/mailman/listinfo/tclug-list >