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Reading issue with DD "bad ending head CHS and LBA)

Alex6280 Posted messages 1 Status Member -  
Sannin_WD Posted messages 4316 Status Member -
Hello,

I own a WD Elements 1 TB external hard drive. For a week now, I can't access the contents of the drive: when I plug it into any PC, I hear the sound indicating a USB key and the drive lights up and spins. But it does not appear under its correct name in "Computer" and I can't access it or view its properties. In "Computer Management" I can't access Disk Management because as soon as I connect the drive, my PC becomes slow and I have to disconnect it directly to unlock the PC.

I downloaded testdisk to see where the problem comes from. It tells me that I am on an EFI GPT partition and it notes an error "Bad ending head < CHS and LBA". I don't know what to do to resolve this problem, the drive isn't old. Could someone please help me?

Thanks in advance!

1 answer

  1.
    Sannin_WD Posted messages 4316 Status Member 758
     
    Welcome to the Forum, Alex6280 :)

    This behavior is not a good sign … If the HDD reacts this way under Windows, we might consider reviewing the symptoms in another logical environment. For this reason I suggest you test a Linux Live CD.

    @Alex6280, most often such reactions coming from a HDD would indicate extreme fatigue of the storage media. Depending on how important the data the HDD stores is to you, an intervention by data recovery professionals could be contemplated.

    Besides, as for the software you have implemented and the specific error messages it reports, it would be better to inquire with the software developers. The experts of the Forum dedicated to that software would give you more information. If you don’t know that forum, we could consider running an online search while using keywords like [software name]+forum. The results would direct you to the proper URL ;)

    Indeed, we could always think of diagnosing the HDD with the manufacturer's utility (WD Data Lifeguard Diagnostics for Windows), but I advise leaving this analysis for the end, after data recovery.

    Just for a little history:

    CHS (Cylinder-head-sector) is an older method of giving addresses to each data block on the hard drive (e.g., cylinder/head/sector is 1024/16/256 - imagine geographic coordinates ;) ).

    LBA (Logical block addressing) is another scheme used to specify the position of data blocks on a storage medium like an HDD. LBA uses just a number for addressing (e.g., block 0, block 1, etc.). Thus, the HDD controller maps the LBA block (block 0, for example) to a physical CHS addressing (block 0, 0, 1, for example). So logical block 0 is mapped by the HDD controller to 0, 0, 1 (just for the sake of the example).

    Nowadays we use LBA which is the logical addressing: a logical block number that the HDD controller maps to physical CHS.

    To my knowledge this message, Bad ending head (CHS and LBA don't match), means that the software reporting it is making a faulty recognition of the HDD geometry.

    @Alex6280, if you decide to receive the experts’ opinion from the Forum I mentioned, would you be able to come back here to share the outcome, please :)

    Thanks and @+!
    Fingers crossed!

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