partition recovery question resolution

From: Aaron Dewell (acd_at_woods.net)
Date: 09/07/03

  • Next message: Sam Ravnborg: "Re: 2.6: spurious recompiles" 
    Date:	Sat, 6 Sep 2003 23:43:17 -0600 (MDT)
To: linux-kernel@vger.kernel.org

    Hi all,

    I ended up resolving the question I posted last week. The reason the partition
    devices read all zeros was because, in fact, those positions on the disk were
    all zeros. Somehow, everything past 1.1 GB got set to all zeros on the disk,
    so it was all correct. I was confused trying to resolve that with a backup (dd)
    copy of the disk that I had, which I finally noticed was about 1.1 GB long, not
    4.3 as I was expecting. Thus the inconsistancies that I was seeing.

    Anyway, thanks for the input.

    I am somewhat curious how it got zerod in the first place. I wasn't working on
    it at first, but the person who was claims the file started at 4.3 GB (the right
    size). So, at some point it got truncated. The modification time was not
    updated on the file. Doing a dd back to the disk with a short file shouldn't
    affect anything past the end of the file, right? Therefore, there would have
    had to have been some kind of condition whereby the file got truncated while a
    dd was going on, and for some reason, it started writing zeros instead of
    stopping.

    It doesn't matter for my problem at this point, since the files are gone either
    way, but it might make an interesting academic question. :-)

    Aaron

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

  • Next message: Sam Ravnborg: "Re: 2.6: spurious recompiles"

    Relevant Pages

    • Re: [PATCH] adding two new options to cp
      ... existing holes", which is not the same thing. ... am copying directories, I'll still have to resort to some ... I want zeros on the disk in the destination ...
      (freebsd-hackers)
    • Re: Does solaris require disks to be zeroed before using
      ... >> zeros written to them before partitioning and building a file system ... >> a good idea to zero all blocks on the disk before using them. ...
      (comp.sys.sun.admin)
    • Re: Starting again...(partitioning...)
      ... erasing past history is simply a matter of writing zeros over the entire disk before installing the operating system from installation media. ... the "past history" remains available for those who get the actual HDD; only physical destruction of the HDD would make that data unrecoverable... ...
      (microsoft.public.windows.vista.general)
    • Re: copying a disk image to restore on linux
      ... to zero out all of the unused space first, so it will compress better. ... the disk is full, then delete the file. ... should have highly compressable zeros in it. ...
      (Security-Basics)
    • Re: blanking DVD+RW
      ... Simply using dvd+rw-format doesn't erase all of the previous contents of the ... whereas overwriting with zeros as you've done will obscure the old data ... disk which has been written full of zeros. ... forensics technology probably could read a zeroed DVD, ...
      (freebsd-questions)