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The external hard drive which contains all my photos and where I backed-up all my important documents is no longer recognized. It is a three month old 500GB Iomage Prestige Desktop Hard Drive.

When I plug it in, it is recognised as a USB device, because it shows up when I type lsusb, but dmesg gives this error message.

[19712.013250] usb 2-2: new high speed USB device using ehci_hcd and address 21
[19712.145347] usb 2-2: configuration #1 chosen from 1 choice
[19712.147214] scsi25 : SCSI emulation for USB Mass Storage devices
[19712.147514] usb-storage: device found at 21
[19712.147519] usb-storage: waiting for device to settle before scanning
[19717.148978] usb-storage: device scan complete
[19717.149527] scsi 25:0:0:0: Direct-Access     ST350082 0AS                   PQ: 0 ANSI: 2 CCS
[19717.151020] sd 25:0:0:0: Attached scsi generic sg2 type 0
[19717.151685] sd 25:0:0:0: [sdb] 976773168 512-byte logical blocks: (500 GB/465 GiB)
[19717.160402] sd 25:0:0:0: [sdb] Write Protect is off
[19717.160412] sd 25:0:0:0: [sdb] Mode Sense: 34 00 00 00
[19717.160418] sd 25:0:0:0: [sdb] Assuming drive cache: write through
[19717.165685] sd 25:0:0:0: [sdb] Assuming drive cache: write through
[19717.165691]  sdb: sdb1
[19719.171808] sd 25:0:0:0: [sdb] Assuming drive cache: write through
[19719.171818] sd 25:0:0:0: [sdb] Attached SCSI disk
[19737.430998] sd 25:0:0:0: [sdb] Unhandled sense code
[19737.431007] sd 25:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[19737.431016] sd 25:0:0:0: [sdb] Sense Key : Medium Error [current] 
[19737.431027] sd 25:0:0:0: [sdb] Add. Sense: Unrecovered read error
[19737.431038] end_request: I/O error, dev sdb, sector 6160463
[19737.431050] Buffer I/O error on device sdb1, logical block 6160400
[19737.431060] Buffer I/O error on device sdb1, logical block 6160401
[19737.431067] Buffer I/O error on device sdb1, logical block 6160402
[19737.431075] Buffer I/O error on device sdb1, logical block 6160403
[19737.431082] Buffer I/O error on device sdb1, logical block 6160404
[19737.431088] Buffer I/O error on device sdb1, logical block 6160405
[19737.431096] Buffer I/O error on device sdb1, logical block 6160406
[19737.431102] Buffer I/O error on device sdb1, logical block 6160407
[19737.431114] Buffer I/O error on device sdb1, logical block 6160408
[19737.431121] Buffer I/O error on device sdb1, logical block 6160409
[19737.712183] sd 6:0:0:0: [sdb] Unhandled sense code
[19737.712191] sd 6:0:0:0: [sdb] Result: hostbyte=DID_ERROR driverbyte=DRIVER_SENSE
[19737.712200] sd 6:0:0:0: [sdb] Sense Key : Hardware Error [current] 
[19737.712210] sd 6:0:0:0: [sdb] Add. Sense: No additional sense information
[19737.712222] end_request: I/O error, dev sdb, sector 0
[19737.712232] Buffer I/O error on device sdb, logical block 0

Neither does the external drive show when I use fdisk:

jeroen@phalacrocorax:~$ sudo fdisk -l
[sudo] password for jeroen: 

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000341ad

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1       18714   150320173+  83  Linux
/dev/sda2           18715       19457     5968147+   5  Extended
/dev/sda5           18715       19457     5968116   82  Linux swap / Solaris`

I popped the disk out of the casing put it on a SATA connect internally and then tried the file recovery programs testdisk/photorec and SpinRite, but both failed because they couldn't recognize the external harddisk.

Do I have any other options?

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3 Answers

up vote 1 down vote accepted

That dmesg error means that the kernel is failing to access the device. If the kernel can't get at the disk, fdisk won't find it either, fdisk uses the Linux drivers in order to access the hard drive.

This is not likely to be a software problem.

An external drive has a regular hard-disk inside it. Your best bet at this point is to figure out whether it is the enclosure that is broken, or the drive. If you are lucky it is only the enclosure that is damaged, and the hard disk can be attached directly to your computer or put in an alternate enclosure to recover the data. Otherwise you could opt for paying for data recovery, if you think it is worth the money.

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I had a problem where my disk was not accessible from my iMac, even with low level tools such as testdisk, fdisk and even dd. I just booted on a Linux Live CD and was able to restore everything.

You may want to check a similar way: try to connect your disk on another OS.

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Does not look like a software problem. You could : - connect the drive to another USB port , that port could be defective - connect the drive to another system and check if it gets recognized - check/change the USB cable

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The OP already stated that he pulled the drive out of the external enclosure and plugged it in directly to a SATA port. It is not a USB issue. –  firedfly Sep 23 '10 at 11:25
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