external hdd, best practice

Discussion in 'Mac Accessories' started by RoxStrongo, May 3, 2006.

  1. RoxStrongo macrumors regular

    RoxStrongo

    Joined:
    Oct 8, 2005
    Location:
    Bournemouth, UK
    #1
    i have an external firewire hdd which i leave plugged into my desktop all the time and has now become irrepairable by disk utility. could the constant connection have caused this and what do you reccomend i can do to fix it?
     
  2. khisayruou macrumors 6502a

    khisayruou

    Joined:
    Aug 21, 2004
    #2
    Its possible, everything undergoes wear and tear.
    Check the warranty on the hard drive and see if you can get it replaced.

    What exactly is irrepairable by disk utility?
     
  3. emaja macrumors 68000

    Joined:
    May 3, 2005
    Location:
    Chicago, IL
    #3
    I am not sure what that means either, but if your data that was on the drive is still somewhere else in a backup, why not do a full re-format? That will mark any bad sectors and should allow it to be used again.
     
  4. RoxStrongo thread starter macrumors regular

    RoxStrongo

    Joined:
    Oct 8, 2005
    Location:
    Bournemouth, UK
    #4
    its out of warranty now i'm guessing, had it a few years. these are the messages that i get from disk utility:

    Invalid node structure
    Volume check failed.

    Error: The underlying task reported failure on exit

    I'm assuming my data is still intact, just unmountable. can anyone reccomend a means of retrieval?
     
  5. mrichmon macrumors 6502a

    Joined:
    Jun 17, 2003
    #5
    In general, a hard drive that is connected but not in use will spin down after a period of inactivity (by default 10 minutes). Spotlight indexing of external drives will occassionally cause the drive to spin up even when noone is using the computer.

    Ultimately, a hard drive is a mechanical device and will wear out over time. From what you are describing it sounds like you have a few bad sectors. This can be repaired by reformating the drive but this causes you to loose the data on the drive. Often bad sectors on older drives are caused by the magnetic coating on the disk itself disintegrating or loosing its ability to maintain a bit setting. This happens due to the age of the material and will happen to a drive irrespective of whether the drive has been powered on all the time or is only turned on occassionally. The other cause of drives wearing out is when the drive bearing or head mechanism is physically worn out due to a lot of use. This second cause does not appear to apply in your case.

    In terms of retreiving the data then you are probably out of luck. There are a few important sections of a hard disk that contain the mount information and the start of the directory index. DiskUtility should be able to repair problems in these areas in many cases. However, if the disk problem cannot be repaired by DiskUtility and the disk is not mountable then there are few remaining options short of very expensive data retreival services (upwards of $3k) or manually reconstructing the data by creating a disk image of the drive and attempting to stitch the data together by hand.

    You could try booting to single user mode and running fdisk on the drive. This might resolve the directory issues on the disk enough for you to be able to mount and copy the data off the drive.
     
  6. RoxStrongo thread starter macrumors regular

    RoxStrongo

    Joined:
    Oct 8, 2005
    Location:
    Bournemouth, UK
    #6
    i would be very grateful of more details to boot from single user mode and run fdisk as at present im not sure how the process works.

    i thought there mite b a problem with the drive when it kept giving errors while trying to copy data. i then ran disk utility which unmouted it and then couldn't remount it. what i have found odd is that wile the drive is still attached to the computer it stops my ipod from working properly wile connected with firewire, but when it is connected with usb it works fine. what might be causing this?
     
  7. mrichmon macrumors 6502a

    Joined:
    Jun 17, 2003
    #7
    It might be due to errors on the firewire bus being caused by the external drive. But the actual cause would depend on how the devices are connected together.

    The easiest way is to boot from your OS X installer disks then instead of starting to install OS X, go to the File menu and select DiskUtility. When DiskUtility opens click on your external drive, select the "FirstAid" tab and click "RepairDisk". This will do the equivalent of fdisk from single user mode. (Yes this should be the same as how you have used DiskUtility in the past, but booting from the OS X install disk ensures that nothing on the external drive is in use. Any files in use on the external drive would prevent DiskUtility from repairing the drive.)
     
  8. RoxStrongo thread starter macrumors regular

    RoxStrongo

    Joined:
    Oct 8, 2005
    Location:
    Bournemouth, UK
    #8
    i have a g5 tower and so the drive connects to the rear 400 port and the ipod to the front one.

    thanks very much, i shall dig out the installer disk and give that a try.
     
  9. RoxStrongo thread starter macrumors regular

    RoxStrongo

    Joined:
    Oct 8, 2005
    Location:
    Bournemouth, UK
    #9
    most interesting was that when i ran disk utility off the install disc it found no problem with the drive whatsoever and it now seems to be working as normal.
     

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