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  • PC Backup Problems Bleg

    Posted by Jonathan on November 30th, 2007 (All posts by )

    For the past few years I’ve successfully used xxcopy to backup data to portable hard drives. However, a few days ago, while I was copying the contents of one portable HD to another, with both HDs connected to the same computer via USB 2.0 connections, something happened in the middle of a backup and the source HD became corrupted. (The first symptom of a problem was that the backup stopped and a Windows message balloon appeared indicating that a particular source file could not be read and that I should run CHKDSK on the source HD.)

    Subsequently it was impossible to read any files on the source HD, and the Windows disk-admin program showed the HD as healthy but as unpartitioned and unformatted. Diagnostics showed no mechanical problems with the HD, and I am able to recover its data using Seagate’s File Recovery utility. Apparently only the HD’s NTFS file-allocation data were corrupted.

    Of course I want to know what happened so that I can prevent it from happening again. I don’t know if this was a hardware or software error. The computer is running WinXP Pro SP2 which I updated with the latest patches about a week ago. I used xxcopy software as I mentioned. Both portable HDs and the computer were plugged into battery-backup power supplies. The computer is a few years old and does not have native USB 2.0; it has a Belkin USB 2.0 card installed.

    My first thought was that there is a problem with xxcopy. My second thought was that there may be a hardware issue related to a USB cable or to the Belkin USB 2.0 card. Another possibility is some kind of driver problem under high-throughput conditions, but this seems least likely.

    Googling on “xxcopy data corruption” doesn’t yield any obvious problems, and xxcopy has been around for a long time. I’ll wait until after my current data-restoration project finishes and then will check the Belkin USB 2.0 card. I’m leaning toward that or a cable as the cause of the problem, since I noticed a short while ago that the computer fails to recognize a USB device plugged into a cable inserted into one of the unused USB receptacles on the Belkin card. (Unfortunately I did some computer maintenance after the HD debacle and did not make a record of which HD was plugged into which USB receptacle.)

    Does anyone have any thoughts or suggestions here? Thanks.

     

    5 Responses to “PC Backup Problems Bleg”

    1. Shannon Love Says:

      … HD as healthy but as unpartitioned and unformatted.

      The master directory block or master directory record as they call it under Windows, was corrupted. That wiped out all information on the drive about partitions and volumes. Its unrecoverable save by a bit level reconstruction which is a chore to say the least.

      The error was caused by a low level failure either in the HD driver or hardware or in the backup software. Backup software sometimes gets confused about which drive is which and writes to the source drive. In either case it maybe a fluke but you should check for a hardware failure on the drive before putting it back in use. I recommend a full reformat and repeated full zero overwrites to test if the hardware can properly create, maintain and locate the master directory record.

      If it passes, put it back service otherwise replace it.

    2. Jonathan Says:

      Good advice on the HD. I’ll run low-level diagnostics after I recover the data. The Seagate program seems to be able to recover the data and the directory structure, but it is slow — it’s been running for about 13 hours and has recovered ~100gb, and there’s another ~100gb to go. Best outcome here would be to find that my problem was caused by a simple HD failure.

      The first release of Microsoft Windows NT 3.51 had an interesting bug. If you created multiple logical drives on your system’s only HD and then attempted to open them for viewing in the Windows disk-admin program it would wipe out the file allocation table irrecoverably. Guess how I learned this.

    3. Shannon Love Says:

      Jonathan,

      I haven’t said it. I won’t say it. Aren’t you proud of my self-restraint?

    4. Robert Schwartz Says:

      If you can recover the data do so. But hard drives are too cheap to loose sleep over. I just bought 400 GB IDE drives for $90/ea at MicroCenter. http://www.microcenter.com/ (2 retail outlets in metro Chicago, Elston bet Fullerton and Diversy and one in west suburbs).

      I do note that I have had many more problems with drives in USB enclosures than with drives in computers. I do not know why, or even if there is a pattern.

    5. Jonathan Says:

      Robert, thanks. I don’t care about the drive, only the data. This is the first portable HD that’s failed on me, but I’ve read comments like yours elsewhere.

      Shannon, I have an additional backup. However, since I don’t understand the initial failure, I want to restore as much data as possible without risking my remaining backup.