Re: Default number of overwrites in shred

[Peter Eckersley]

On Fri, 2007-05-04 at 09:14 +0200, Jim Meyering wrote:
> Paul Eggert <address@hidden> wrote:
> > Peter Eckersley <address@hidden> writes:
> >
> >> I was wondering if you would consider reducing the number of default
> >> overwrites for "shred" from 25 to something more like 5?
> >
> > As near as I can make out, for modern disks the default should be 1.
> > That's easy to change.  Any objections?
> 
> Hi Paul,
> 
> My reflex was to object.  Reducing the default number of passes from
> 25 to 1 seemed extreme.  But after skimming through the link below,
> it's hard to argue :-)

Really?  For "Top Secret+" material, their "secure erase newsletter"
calls for 2 write passes, offset slightly on either side of the track (p
4).

> 
> > There's also the Secure Erase facility built into modern ATA drives,
> > which it sounds like 'shred' should use if it's available.
> > Does anybody know how well GNU/Linux supports it?
> > See <http://cmrr.ucsd.edu/hughes/SecureErase.html>.
-- 
Peter Eckersley                            address@hidden
Staff Technologist                Tel  +1 415 436 9333 x131
Electronic Frontier Foundation    Fax  +1 415 436 9993