Gdisk crap

Discussion in 'NZ Computing' started by Rob J, Jul 27, 2005.

  1. Rob J

    Rob J Guest

    Well. I used Gdisk to "supposedly" wipe a disk which is supposed to
    wipe it and delete the partition. Then I type C: and it works. And I
    do a dir of C: and it shows me all the files and folders in C:\
    And the free space displayed is the same as it was before.

    Then I ask Gdisk for disk info and it tells me there are no
    partititions on this disk at all. Yeah right!

    Then I tell Gdisk to create a partition, make it the primary, and
    format it. Then go to C: and dir and the drive is not empty. It shows
    exactly the same info before.

    Now, every time before now that I formatted a disk, I expect there to
    be no files or folders visible, and the free space reported to be the
    correct amount.

    Does Gdisk really do anything, apart from lying to the user about
    erasing their hard drive and the structure of their disk?
    Rob J, Jul 27, 2005
    #1
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  2. Rob J

    Guest

    gdisk has worked well for a number of people for a number of years now.

    How about some more info - what is your disk layout, what command line
    parameters did you use?
    , Jul 27, 2005
    #2
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  3. Rob J

    Rob J Guest

    Anyone want to recommend a nice free disk wiper that works?

    On Thu, 28 Jul 2005 02:36:05 +1200, Rob J <> wrote:

    >
    >Well. I used Gdisk to "supposedly" wipe a disk which is supposed to
    >wipe it and delete the partition. Then I type C: and it works. And I
    >do a dir of C: and it shows me all the files and folders in C:\
    >And the free space displayed is the same as it was before.
    >
    >Then I ask Gdisk for disk info and it tells me there are no
    >partititions on this disk at all. Yeah right!
    >
    >Then I tell Gdisk to create a partition, make it the primary, and
    >format it. Then go to C: and dir and the drive is not empty. It shows
    >exactly the same info before.
    >
    >Now, every time before now that I formatted a disk, I expect there to
    >be no files or folders visible, and the free space reported to be the
    >correct amount.
    >
    >Does Gdisk really do anything, apart from lying to the user about
    >erasing their hard drive and the structure of their disk?
    Rob J, Jul 27, 2005
    #3
  4. Rob J

    Gordon Smith Guest

    Rob J wrote:
    > Well. I used Gdisk to "supposedly" wipe a disk which is supposed to
    > wipe it and delete the partition. Then I type C: and it works. And I
    > do a dir of C: and it shows me all the files and folders in C:\
    > And the free space displayed is the same as it was before.
    >
    > Then I ask Gdisk for disk info and it tells me there are no
    > partititions on this disk at all. Yeah right!
    >
    > Then I tell Gdisk to create a partition, make it the primary, and
    > format it. Then go to C: and dir and the drive is not empty. It shows
    > exactly the same info before.
    >
    > Now, every time before now that I formatted a disk, I expect there to
    > be no files or folders visible, and the free space reported to be the
    > correct amount.
    >
    > Does Gdisk really do anything, apart from lying to the user about
    > erasing their hard drive and the structure of their disk?
    >


    And you are actually using it running off of a bootable floppy?
    Not doing something silly, like running gdisk32 from within windows?
    Gordon Smith, Jul 28, 2005
    #4
  5. Rob J

    Shane Guest

    On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:

    > Anyone want to recommend a nice free disk wiper that works?
    >

    Its a pity your not a linux user,
    dd if=/dev/null of=/dev/hdb bs=512
    would be more than fine, or if the filesystem isnt journalled then man
    shred would be fine,
    I assume you want to overwrite any data on the drive to make damn sure an
    app cant recover it.


    --
    Hardware, n.: The parts of a computer system that can be kicked

    The best way to get the right answer on usenet is to post the wrong one.
    Shane, Jul 28, 2005
    #5
  6. Rob J

    Harry Guest

    Shane wrote:

    > On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >
    >> Anyone want to recommend a nice free disk wiper that works?
    >>

    > Its a pity your not a linux user,
    > dd if=/dev/null of=/dev/hdb bs=512
    > would be more than fine, or if the filesystem isnt journalled then man
    > shred would be fine,
    > I assume you want to overwrite any data on the drive to make damn sure an
    > app cant recover it.
    >
    >


    Better still would be "shred /dev/hdb1" or similar.
    I wouldn't try erasing all of /dev/hdb because that would include
    *all* partitions.
    Harry, Jul 28, 2005
    #6
  7. Rob J

    Enkidu Guest

    Shane wrote:
    > On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >
    >
    >>Anyone want to recommend a nice free disk wiper that works?
    >>

    >
    > Its a pity your not a linux user,
    > dd if=/dev/null of=/dev/hdb bs=512
    > would be more than fine, or if the filesystem isnt
    > journalled then man shred would be fine,
    > I assume you want to overwrite any data on the drive
    > to make damn sure an app cant recover it.
    >

    Knoppix.

    Cheers,

    Cliff

    --

    Barzoomian the Martian - http://barzoomian.blogspot.com
    Enkidu, Jul 28, 2005
    #7
  8. Rob J

    Dave Taylor Guest

    Rob J <> wrote in
    news::

    > Anyone want to recommend a nice free disk wiper that works?


    DBAN
    http://dban.sourceforge.net/
    Darik's Boot and Nuke ("DBAN") is a self-contained boot floppy that
    securely wipes the hard disks of most computers. DBAN will automatically
    and completely delete the contents of any hard disk that it can detect,
    which makes it an appropriate utility for bulk or emergency data
    destruction.

    --
    Ciao, Dave
    Dave Taylor, Jul 28, 2005
    #8
  9. Rob J

    Steve Guest

    On Thu, 28 Jul 2005 17:20:12 +1000, Harry wrote:

    > Shane wrote:
    >
    >> On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >>
    >>> Anyone want to recommend a nice free disk wiper that works?
    >>>

    >> Its a pity your not a linux user,
    >> dd if=/dev/null of=/dev/hdb bs=512
    >> would be more than fine, or if the filesystem isnt journalled then man
    >> shred would be fine,
    >> I assume you want to overwrite any data on the drive to make damn sure
    >> an app cant recover it.
    >>
    >>
    >>

    > Better still would be "shred /dev/hdb1" or similar. I wouldn't try erasing
    > all of /dev/hdb because that would include *all* partitions.


    Don't fool yourself. The only way to ensure the destruction of data is an
    oxyacetylene torch.

    Steve
    Steve, Jul 28, 2005
    #9
  10. Rob J

    Harry Guest

    Steve wrote:

    > On Thu, 28 Jul 2005 17:20:12 +1000, Harry wrote:
    >
    >> Shane wrote:
    >>
    >>> On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >>>
    >>>> Anyone want to recommend a nice free disk wiper that works?
    >>>>
    >>> Its a pity your not a linux user,
    >>> dd if=/dev/null of=/dev/hdb bs=512
    >>> would be more than fine, or if the filesystem isnt journalled then man
    >>> shred would be fine,
    >>> I assume you want to overwrite any data on the drive to make damn sure
    >>> an app cant recover it.
    >>>
    >>>
    >>>

    >> Better still would be "shred /dev/hdb1" or similar. I wouldn't try
    >> erasing all of /dev/hdb because that would include *all* partitions.

    >
    > Don't fool yourself. The only way to ensure the destruction of data is an
    > oxyacetylene torch.
    >


    Really? So an oxyacetylene torch will burn a "1" in the same way
    as it burns a "0"? I don't think so.

    The best way to secure data is to store in UXROM.
    Harry, Jul 28, 2005
    #10
  11. Rob J

    Enkidu Guest

    Harry wrote:
    > Steve wrote:
    >
    >
    >>On Thu, 28 Jul 2005 17:20:12 +1000, Harry wrote:
    >>
    >>
    >>>Shane wrote:
    >>>
    >>>
    >>>>On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >>>>
    >>>>
    >>>>>Anyone want to recommend a nice free disk wiper that works?
    >>>>>
    >>>>
    >>>>Its a pity your not a linux user,
    >>>>dd if=/dev/null of=/dev/hdb bs=512
    >>>>would be more than fine, or if the filesystem isnt journalled then man
    >>>>shred would be fine,
    >>>>I assume you want to overwrite any data on the drive to make damn sure
    >>>>an app cant recover it.
    >>>>
    >>>>
    >>>>
    >>>
    >>>Better still would be "shred /dev/hdb1" or similar. I wouldn't try
    >>>erasing all of /dev/hdb because that would include *all* partitions.

    >>
    >>Don't fool yourself. The only way to ensure the destruction of data is an
    >>oxyacetylene torch.

    >
    > Really? So an oxyacetylene torch will burn a "1" in the same way
    > as it burns a "0"? I don't think so.
    >
    > The best way to secure data is to store in UXROM.
    >

    He said "destruction".

    Cheers,

    Cliff

    --

    Barzoomian the Martian - http://barzoomian.blogspot.com
    Enkidu, Jul 29, 2005
    #11
  12. Rob J

    Harry Guest

    Enkidu wrote:

    > Harry wrote:
    >> Steve wrote:
    >>
    >>
    >>>On Thu, 28 Jul 2005 17:20:12 +1000, Harry wrote:
    >>>
    >>>
    >>>>Shane wrote:
    >>>>
    >>>>
    >>>>>On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >>>>>
    >>>>>
    >>>>>>Anyone want to recommend a nice free disk wiper that works?
    >>>>>>
    >>>>>
    >>>>>Its a pity your not a linux user,
    >>>>>dd if=/dev/null of=/dev/hdb bs=512
    >>>>>would be more than fine, or if the filesystem isnt journalled then man
    >>>>>shred would be fine,
    >>>>>I assume you want to overwrite any data on the drive to make damn sure
    >>>>>an app cant recover it.
    >>>>>
    >>>>>
    >>>>>
    >>>>
    >>>>Better still would be "shred /dev/hdb1" or similar. I wouldn't try
    >>>>erasing all of /dev/hdb because that would include *all* partitions.
    >>>
    >>>Don't fool yourself. The only way to ensure the destruction of data is an
    >>>oxyacetylene torch.

    >>
    >> Really? So an oxyacetylene torch will burn a "1" in the same way
    >> as it burns a "0"? I don't think so.
    >>
    >> The best way to secure data is to store in UXROM.
    >>

    > He said "destruction".
    >


    He said "destruction of data".
    Harry, Jul 29, 2005
    #12
  13. Rob J

    Gordon Guest

    On Thu, 28 Jul 2005 19:36:07 +1200, Dave Taylor wrote:

    > DBAN
    > http://dban.sourceforge.net/
    > Darik's Boot and Nuke ("DBAN") is a self-contained boot floppy that
    > securely wipes the hard disks of most computers. DBAN will automatically
    > and completely delete the contents of any hard disk that it can detect,
    > which makes it an appropriate utility for bulk or emergency data
    > destruction.


    And be careful you hide the HD you want data on afterwards.
    Gordon, Jul 29, 2005
    #13
  14. Rob J

    Dave Taylor Guest

    Gordon <> wrote in
    news:p:

    > On Thu, 28 Jul 2005 19:36:07 +1200, Dave Taylor wrote:
    >
    >> DBAN
    >> http://dban.sourceforge.net/
    >> Darik's Boot and Nuke ("DBAN") is a self-contained boot floppy that
    >> securely wipes the hard disks of most computers. DBAN will
    >> automatically and completely delete the contents of any hard disk
    >> that it can detect, which makes it an appropriate utility for bulk or
    >> emergency data destruction.

    >
    > And be careful you hide the HD you want data on afterwards.
    >
    >


    I just boot it, press enter, select the drive and method. It sounds scary
    but it is not actually automatic unless you make it so. I know what drive
    my external cable goes to in my wipe/ghosting box.

    --
    Ciao, Dave
    Dave Taylor, Jul 29, 2005
    #14
  15. In article <-a-geek.net>,
    Shane <-a-geek.net> wrote:

    >dd if=/dev/null of=/dev/hdb bs=512


    Actually, that won't achieve anything. You probably mean

    dd if=/dev/zero of=/dev/hdb bs=512

    Or better still, how about a few passes of

    dd if=/dev/urandom of=/dev/hdb bs=512

    heh-heh...
    Lawrence D’Oliveiro, Jul 29, 2005
    #15
  16. In article <>,
    Harry <> wrote:

    >Enkidu wrote:
    >
    >> Harry wrote:
    >>> Steve wrote:
    >>>
    >>>
    >>>>On Thu, 28 Jul 2005 17:20:12 +1000, Harry wrote:
    >>>>
    >>>>
    >>>>>Shane wrote:
    >>>>>
    >>>>>
    >>>>>>On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >>>>>>
    >>>>>>
    >>>>>>>Anyone want to recommend a nice free disk wiper that works?
    >>>>>>>
    >>>>>>
    >>>>>>Its a pity your not a linux user,
    >>>>>>dd if=/dev/null of=/dev/hdb bs=512
    >>>>>>would be more than fine, or if the filesystem isnt journalled then man
    >>>>>>shred would be fine,
    >>>>>>I assume you want to overwrite any data on the drive to make damn sure
    >>>>>>an app cant recover it.
    >>>>>>
    >>>>>>
    >>>>>>
    >>>>>
    >>>>>Better still would be "shred /dev/hdb1" or similar. I wouldn't try
    >>>>>erasing all of /dev/hdb because that would include *all* partitions.
    >>>>
    >>>>Don't fool yourself. The only way to ensure the destruction of data is an
    >>>>oxyacetylene torch.
    >>>
    >>> Really? So an oxyacetylene torch will burn a "1" in the same way
    >>> as it burns a "0"? I don't think so.
    >>>
    >>> The best way to secure data is to store in UXROM.
    >>>

    >> He said "destruction".

    >
    >He said "destruction of data".


    He didn't say "secure data".
    Lawrence D'Oliveiro, Jul 29, 2005
    #16
  17. Rob J

    Harry Guest

    Lawrence D’Oliveiro wrote:

    > In article <-a-geek.net>,
    > Shane <-a-geek.net> wrote:
    >
    >>dd if=/dev/null of=/dev/hdb bs=512

    >
    > Actually, that won't achieve anything. You probably mean
    >
    > dd if=/dev/zero of=/dev/hdb bs=512
    >
    > Or better still, how about a few passes of
    >
    > dd if=/dev/urandom of=/dev/hdb bs=512
    >
    > heh-heh...


    You'd probably be much better using bs=4096.
    This will improve the speed by a factor of at least 4.

    BTW /dev/urandom is very very slow because it deliberately uses
    complex entropy and time-dependent algorithm.
    Harry, Jul 29, 2005
    #17
  18. Rob J

    Harry Guest

    Lawrence D'Oliveiro wrote:

    > In article <>,
    > Harry <> wrote:
    >
    >>Enkidu wrote:
    >>
    >>> Harry wrote:
    >>>> Steve wrote:
    >>>>
    >>>>
    >>>>>On Thu, 28 Jul 2005 17:20:12 +1000, Harry wrote:
    >>>>>
    >>>>>
    >>>>>>Shane wrote:
    >>>>>>
    >>>>>>
    >>>>>>>On Thu, 28 Jul 2005 09:46:45 +1200, Rob J wrote:
    >>>>>>>
    >>>>>>>
    >>>>>>>>Anyone want to recommend a nice free disk wiper that works?
    >>>>>>>>
    >>>>>>>
    >>>>>>>Its a pity your not a linux user,
    >>>>>>>dd if=/dev/null of=/dev/hdb bs=512
    >>>>>>>would be more than fine, or if the filesystem isnt journalled then
    >>>>>>>man shred would be fine,
    >>>>>>>I assume you want to overwrite any data on the drive to make damn
    >>>>>>>sure an app cant recover it.
    >>>>>>>
    >>>>>>>
    >>>>>>>
    >>>>>>
    >>>>>>Better still would be "shred /dev/hdb1" or similar. I wouldn't try
    >>>>>>erasing all of /dev/hdb because that would include *all* partitions.
    >>>>>
    >>>>>Don't fool yourself. The only way to ensure the destruction of data is
    >>>>>an oxyacetylene torch.
    >>>>
    >>>> Really? So an oxyacetylene torch will burn a "1" in the same way
    >>>> as it burns a "0"? I don't think so.
    >>>>
    >>>> The best way to secure data is to store in UXROM.
    >>>>
    >>> He said "destruction".

    >>
    >>He said "destruction of data".

    >
    > He didn't say "secure data".


    And he didn't say "destruction of secure data".
    Harry, Jul 29, 2005
    #18
  19. In article <>,
    Harry <> wrote:

    >Lawrence D'Oliveiro wrote:
    >
    >> dd if=/dev/urandom of=/dev/hdb bs=512

    >
    >You'd probably be much better using bs=4096.
    >This will improve the speed by a factor of at least 4.


    But it might miss out up to 7 odd sectors at the end, depending on the
    exact size of the disk.

    Hmm, I can't see any easy way to get the size of an unmounted disk from
    a shell command (need to do a BLKGETSIZE ioctl).

    >BTW /dev/urandom is very very slow because it deliberately uses
    >complex entropy and time-dependent algorithm.


    /dev/urandom never blocks, it's /dev/random that can block when it runs
    out of entropy. /dev/urandom will fake it when it runs short of entropy,
    by falling back on a pseudorandom sequence seeded from the last lot of
    entropy it was able to get.
    Lawrence D¹Oliveiro, Jul 29, 2005
    #19
  20. Rob J

    Harry Guest

    Lawrence D¹Oliveiro wrote:

    > In article <>,
    > Harry <> wrote:
    >
    >>Lawrence D'Oliveiro wrote:
    >>
    >>> dd if=/dev/urandom of=/dev/hdb bs=512

    >>
    >>You'd probably be much better using bs=4096.
    >>This will improve the speed by a factor of at least 4.

    >
    > But it might miss out up to 7 odd sectors at the end, depending on the
    > exact size of the disk.


    No you wont. dd will write partical block sizes.

    >
    > Hmm, I can't see any easy way to get the size of an unmounted disk from
    > a shell command (need to do a BLKGETSIZE ioctl).


    Try trial-and-error. You will soon find what works faster.

    >
    >>BTW /dev/urandom is very very slow because it deliberately uses
    >>complex entropy and time-dependent algorithm.

    >
    > /dev/urandom never blocks, it's /dev/random that can block when it runs
    > out of entropy. /dev/urandom will fake it when it runs short of entropy,
    > by falling back on a pseudorandom sequence seeded from the last lot of
    > entropy it was able to get.


    It is still very slow compared with, for example, /dev/zero.
    Try and compare /dev/zero and /dev/urandom if you dont believe me.
    Harry, Jul 29, 2005
    #20
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