Re: deleting a hard drive

From: AlanP (alan_at_btinternet.com)
Date: 09/14/04

  • Next message: AlanP: "Re: Something's dialing my ISP" 
    Date: Tue, 14 Sep 2004 13:57:55 +0000 (UTC)

    Herbert West wrote:
    > On Sun, 12 Sep 2004 20:41:16 -0400, . <jmark@wowway.com> wrote:
    >
    >
    >>I am enrolled in an on-line Digital Forensics class and the instructor
    >>has asked the following question....Why can't you delete a hard drive?
    >>If he means delete as in rendering every bit empty...holding neither a
    >>1 nor a 0. I don't think that that is possible, is it? Any help would
    >>be appreciated.
    >
    >
    >
    > Each bit holding "neither a 1 nor a 0" sounds more like a question of
    > quantum mechanics and physics (or even philosophy and Taoism) than of
    > digital forensics. I sort of envision a situation like "Shroedinger's
    > Hard Drive," where every possible bit of addressable surface area on
    > the drive is in an inderterminate state until acted upon by an outside
    > force, even if the force is that of an observer spinning the disk
    > while passing a read head over it. The problem is that that the disk
    > is a magnetic surface, and thus can't ever be rendered 100%
    > magnetically neutral. Any specific bit of surface space we examine
    > will have settled in one state or the other, even if only weakly.
    >
    > The instructor probably means that a flat Gaussian random stream of
    > bits would be output when the drive is read. As others have said,
    > degaussing the drive would be the best *physical* way to do it (short
    > of grinding the platter into microscopic dust). <g>
    >
    > Alternatly, we could do our damdest to synthesize a pseudorandom
    > sequence and constantly overwrite the existing data in order to
    > eliminate all traces of the original magnetic patterns. The following
    > link should provide some info.
    >
    > http://www.usenix.org/publications/library/proceedings/sec96/full_papers/gutmann/
    >
    > There are a number of secure deletion utilities based upon the above.
    > Being a Windows user, I like Sammy Tolvanen's "Eraser," a free but
    > effective solution.
    >
    > http://www.tolvanen.com/eraser/

    Wow...

    Awesome topic next time we get munted...

  • Next message: AlanP: "Re: Something's dialing my ISP"

    Relevant Pages

    • Re: deleting a hard drive
      ... >If he means delete as in rendering every bit empty...holding neither a ... quantum mechanics and physics than of ... the drive is in an inderterminate state until acted upon by an outside ... The problem is that that the disk ...
      (alt.computer.security)
    • Re: I/O and rendering
      ... > I'm developing a application which includes opengl rendering of objects, ... > and it requires a lot of realtime i/o reading of data from disk. ... Delays are the secondary worry. ...
      (comp.graphics.algorithms)
    • exporting figures without drawing them
      ... is it possible to plot a figure, export it to disk (say, as a pdf), ... but without rendering the figure to screen? ... i often have scripts that generate and export to disk many figures ...
      (comp.soft-sys.matlab)
    • Re: deleting a hard drive
      ... What a broad and incorrect question. ... Does the instructor mean delete the data on a hard ... If he means the data and not the hard disk itself, degaussing will delete all data and data ...
      (alt.computer.security)
    • Quantcast