Archived from groups: comp.sys.ibm.pc.hardware.storage (
More info?)
Alexander Grigoriev <alegr@earthlink.net> wrote in message
news
uAdc.3311$A_4.1976@newsread1.news.pas.earthlink.net...
> I think all those scares about overwritten data recovery are just
> old wives tales to support "data erasure" software sales, repeated
> many times by such illiterate paranoid folks as Dvorak of PC mag.
Doesnt explain the DOD standards for wiping and the
obsession with melting drives that are being disposed of.
You can however certainly claim that thats just an ultra safe approach
which should ensure that the data cant be retrieved, and not saying
anything useful about how retrievable it is without that.
> It's quite a wonder that the _latest_ written data can be read at
> all, given the current (and even not that current) recording density.
> As the data is overwritten once with any disk-fill software,
> like a drive write test, it becomes pretty much noise added
> to the latest signal, and as noise, cannot be reliably separated
> from the signal to become another decodable signal.
Corse you could be a shill who knows that the data can be
retrieved and who is deliberately encouraging people to
not fully erase their drives, so the data can be retrieved |-)
> "Arno Wagner" <me@privacy.net> wrote in message
> news:c5514a$2olufm$2@ID-2964.news.uni-berlin.de...
> > Previously zero <zeroREMOVEnews2@hotmail.com> wrote:
> > > A) If drive A is copied to drive B just be normal ide cables and drag
> drop
> > > so nothing clever - will the forensic left over magnetic signals be lost
> ?
> >
> > > I am thinking that the clever software that would normally be used in
> these
> > > cases would
> > > be able to record the exact values read of the disc surface before they
> are
> > > approximated
> > > to either 1 or 0 and from that be able to work out what was there
> previously
> >
> > > so . . .
> >
> > > if you drag & drop the exact values are lost and its either 1 or 0 and
> end
> > > of story ?
> >
> > Yes. If you copy data from one drive to the other, you add a new
> > layer of data to the target drive on top of what was there
> > before. Any 'older data layers' on the source drive stay there and
> > are not copied.
> >
> > Still, while it may be possible to remove data in layers and recover
> > older data that was in its space before, no commercial data recovery
> > company offers this service. (The german computer magazin c't
> > tried to get data recoverd that was overwritten once some time
> > ago. All data-recovery outfits they contacted said they could
> > not do this.) It might be impossible to actually do this, e.g.
> > because the overwritten signal is too close to the noise-level.
> > It used to be possible with older HDD technology, that did not
> > use the magnetic coating to its limits. It is likely possible with
> > floppy disks.
> >
> > Arno
> > --
> > For email address: lastname AT tik DOT ee DOT ethz DOT ch
> > GnuPG: ID:1E25338F FP:0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F
> > "The more corrupt the state, the more numerous the laws" - Tacitus
> >
> >
>
>