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  1. tfj
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       #1  
    Could you point me to the original Master Boot Record (with an intact partition table) that I presume
    the USB drive (/dev/mapper/store-media) had at some point during development? (by default the table is
    zero'ed-out).

    I'm trying to undelete a USB drive directory, and the partition info should really help.

    Thanks,

    tfj
  2. Branta's Avatar
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    #2  
    Partition info probably won't help you. The majority of solid state devices implement "wear leveling" technology which randomizes the physical addresses used and uses a virtual translation to convert between physical and logical addresses. If you are seeing zeroed content you are probably looking at the physical address you expect, but the MBR data is somewhere different after the logical mapping. The only solution might be a forensic extraction of the device, and reassemble data the hard way.
  3. tfj
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       #3  
    Quote Originally Posted by Branta View Post
    Partition info probably won't help you. The majority of solid state devices implement "wear leveling" technology which randomizes the physical addresses used and uses a virtual translation to convert between physical and logical addresses. If you are seeing zeroed content you are probably looking at the physical address you expect, but the MBR data is somewhere different after the logical mapping. The only solution might be a forensic extraction of the device, and reassemble data the hard way.
    I grasp that LVM2 is a complicating top-layer of the
    filesystem, but I'm fuzzy on some of your points - are you saying
    that LVM2 and wear-leveling obliterate the old-school filesystem? Is
    there an LVM2 'version' or 'alias' of the USB drive I could be
    focusing on instead?

    Still, I would like to try restoring the partition numbers -
    the first 512-byte chunk of </dev/mapper/store-media> looks like a
    standard MBR, except that the partition table is full of nulls; I
    assume it originally held some values, which were then stripped-out,
    maybe by LVM2.

    I have (mostly) kept the USB drive read-only since the
    accidental erasure of a folder, and have been trying to recover with
    <testdisk>, on a Windows machine. It reports the USB drive (which is
    fully readable) as having 'no partition', and it isn't clear how to
    proceed from there. One early trial did succeed - <testdisk> started
    copying out the erased files - so it *can* recover the folder;
    unfortunately, I didn't keep track of the steps taken to get there.
    I think if I had the original partition info, it may work right away.

    Apparently, <testdisk> understands LVM2, but I can find hardly
    any info about that on the <testdisk> website; I don't know why it
    doesn't recognize the USB drive as being LVM2-based. Maybe I need to
    use a Linux host-machine instead?

    Anyway, could you suggest where to snoop for early,
    developmental versions of </dev/mapper/store-media>?

    Or, could there be a copy of the original MBR hidden
    somewhere on the TP itself (maybe, for example, within
    </dev/.static/dev> - how do you view those files)?

    Thanks,
    tfj
  4. #4  
    You asked for this a month ago. See http://forums.webosnation.com/hp-tou...ot-record.html. Anyway, why not try TestDisk on the device itself? Get an IPK, then push it to the device after you boot a ramdisk.

    BTW, the USB drive mode does not really expose the storage device, but just that one partition.
  5. tfj
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       #5  
    Quote Originally Posted by GMMan View Post
    You asked for this a month ago. See http://forums.webosnation.com/hp-tou...ot-record.html. Anyway, why not try TestDisk on the device itself? Get an IPK, then push it to the device after you boot a ramdisk.

    BTW, the USB drive mode does not really expose the storage device, but just that one partition.
    Well, there's a follow-up message there, but I don't seem to get many follow-up replies, is that normal?

    I may 'boot a ramdisk' after learning more about that, but I may actually be able to connect the TP as a guest-device to my n900 phone and run testdisk. Are there some advantages to running testdisk on-device? To be clear, I only erased one single directory on the USB drive.
  6. #6  
    You can't access any of the on-device storage externally unless you happen to have a dev build of bootie. The IPK for TestDisk should be available in the repository used by OptWare.

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