file recovery - OS2

This is a discussion on file recovery - OS2 ; I have a device that was writing to an SD card when there was a power cut. As expected, the file on the SD card wasn't closed properly. There is a directory entry that the device can see, and it ...

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Thread: file recovery

  1. file recovery

    I have a device that was writing to an SD card when there was a power
    cut. As expected, the file on the SD card wasn't closed properly.
    There is a directory entry that the device can see, and it reports a
    file size of 1.3 GB, which is about right, but the device can't do
    anything with the file. After attaching the device to a computer via
    a USB connection, a directory listing returns the error message about
    the directory entry being corrupted, which is also not a surprise.
    CHKDSK was able to repair the directory entry, but the file was
    apparently truncated to about 1.0 GB in the process. So there are
    probably about 300 MB worth of linked clusters that have no directory
    entry associated with them anymore.

    The question is: can DFSEE recover the linked clusters and associate
    them with a new directory entry? I know that DFSEE can perform an
    undelete, but in this case there is no file to undelete. There was
    one 1.3 GB file before the CHKDSK repair, and there's one 1.0 GB file
    after the repair, so the other 300 MB has been orphaned. Hopefully
    the 300 MB still exists as a single linked chain of clusters. If they
    aren't linked, trying to recreate the exact sequence of clusters for
    300 MB worth of data doesn't seem very practical. Other than the
    CHKDSK repair, I've avoided writing anything to the SD card so that
    the orphaned clusters aren't overwritten.

  2. Re: file recovery

    tholen@antispam.ham wrote:
    > I have a device that was writing to an SD card when there was a power
    > cut. As expected, the file on the SD card wasn't closed properly.
    > There is a directory entry that the device can see, and it reports a
    > file size of 1.3 GB, which is about right, but the device can't do
    > anything with the file. After attaching the device to a computer via
    > a USB connection, a directory listing returns the error message about
    > the directory entry being corrupted, which is also not a surprise.
    > CHKDSK was able to repair the directory entry, but the file was
    > apparently truncated to about 1.0 GB in the process. So there are
    > probably about 300 MB worth of linked clusters that have no directory
    > entry associated with them anymore.
    >
    > The question is: can DFSEE recover the linked clusters and associate
    > them with a new directory entry? I know that DFSEE can perform an
    > undelete, but in this case there is no file to undelete. There was
    > one 1.3 GB file before the CHKDSK repair, and there's one 1.0 GB file
    > after the repair, so the other 300 MB has been orphaned. Hopefully
    > the 300 MB still exists as a single linked chain of clusters. If they
    > aren't linked, trying to recreate the exact sequence of clusters for
    > 300 MB worth of data doesn't seem very practical. Other than the
    > CHKDSK repair, I've avoided writing anything to the SD card so that
    > the orphaned clusters aren't overwritten.


    If you have a snippet of a small portion of the exact data in the lost
    section, you can try a pattern search to find it, and then hope that the
    rest of the data is contiguous. Hard to do if that was your only copy
    of the data though. Hopefully someone else can offer a better method.

    --
    [Reverse the parts of the e-mail address to reply.]

  3. Re: file recovery



    "tholen@antispam.ham" schrieb:
    >
    > I have a device that was writing to an SD card when there was a power
    > cut. As expected, the file on the SD card wasn't closed properly.
    > There is a directory entry that the device can see, and it reports a
    > file size of 1.3 GB, which is about right, but the device can't do
    > anything with the file. After attaching the device to a computer via
    > a USB connection, a directory listing returns the error message about
    > the directory entry being corrupted, which is also not a surprise.
    > CHKDSK was able to repair the directory entry, but the file was
    > apparently truncated to about 1.0 GB in the process. So there are
    > probably about 300 MB worth of linked clusters that have no directory
    > entry associated with them anymore.
    >
    > The question is: can DFSEE recover the linked clusters and associate
    > them with a new directory entry? I know that DFSEE can perform an
    > undelete, but in this case there is no file to undelete. There was
    > one 1.3 GB file before the CHKDSK repair, and there's one 1.0 GB file
    > after the repair, so the other 300 MB has been orphaned. Hopefully
    > the 300 MB still exists as a single linked chain of clusters. If they
    > aren't linked, trying to recreate the exact sequence of clusters for
    > 300 MB worth of data doesn't seem very practical. Other than the
    > CHKDSK repair, I've avoided writing anything to the SD card so that
    > the orphaned clusters aren't overwritten.


    If you have registered DFSee, you could ask Jan.

    Hendrik

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