Formatting USB Drive = capacity shrinks?

Discussion in 'Mac Basics and Help' started by Patrick J, Mar 26, 2010.

  1. Patrick J macrumors 65816

    Patrick J

    Joined:
    Mar 12, 2009
    Location:
    Oporto, Portugal
    #1
    I have a USB Lacie iamaKey drive. It originally had a capacity of 8.09 GB (on Snow Leopard). I has been like that for months.

    Today, I tried to format it with Disk Utility, and now the available space show up as 7.86 GB. I have tried deleting the partition, creating a new one, writing over with zeros, but I can, in no way, recover the lost space.

    Why can I not use the maximum space of my drive?
     
  2. jampat macrumors 6502a

    Joined:
    Mar 17, 2008
    #2
    If this is an 8GB key, I think you had a bigger problem before. Normally 8GB keys only have 7.8 GB of space (8000/1024). Storage manufacturers always divide by 1000 instead of 1024 to make drives appear bigger. I have never seen a drive format with more than the indicated capacity, they all format at ~3% smaller than indicated.
     
  3. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #3
  4. Patrick J thread starter macrumors 65816

    Patrick J

    Joined:
    Mar 12, 2009
    Location:
    Oporto, Portugal
    #4
    I am aware of the Snow Leopard vs Windows/Leopard discrepancies, when regarding file sizes.

    Regardless, is there any reason for me to be losing space?

    Snow Leopard read the original space as 8.09 GB. Now is reads as 7.86.
     
  5. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #5
    What format did you use?
     
  6. Patrick J thread starter macrumors 65816

    Patrick J

    Joined:
    Mar 12, 2009
    Location:
    Oporto, Portugal
    #6
    FAT32. I have tried using Mac OS Extended Journaled with the same results.

    Update: thanks to GGJstudios
    I tried messing around with Options, under the Partition tab, and tried all 3: GUID, Apple Map, and MBR, and under MBR it now shows 8.07GB free space.

    During all this time, under Disk Utility Total Capacity was stated as 8.09GB, so I was sure the space was there, just not being recognized correctly.
     
  7. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #7
    You may have already done this, but in case you haven't:
    • Launch Disk Utility and select the drive
    • Click on the Partition tab
    • Select Volume Scheme: 1 Partition
    • Click Options and select Master Boot Record
    • For Format, select MS-DOS(FAT)
    • Click Apply
     
  8. belvdr macrumors 603

    Joined:
    Aug 15, 2005
    #8
    I wonder if something in the partition is hosed, or there could be some bad parts of the disk.

    If you check dmesg and other console logs, you should see the device it uses, say /dev/disk1.

    You could wipe it out with dd in Terminal.

    ** NOTE **

    I am not responsible if you delete data. You need to make very certain you are wiping the correct drive
     
  9. Patrick J thread starter macrumors 65816

    Patrick J

    Joined:
    Mar 12, 2009
    Location:
    Oporto, Portugal
    #9
    Worked perfectly. I updated above post to help future searchers. Thanks so much.
     
  10. GGJstudios macrumors Westmere

    GGJstudios

    Joined:
    May 16, 2008
    #10
    One other thing to remember is that FAT32 is limited to 4GB file sizes. As yours is an 8GB drive, this may or may not be a concern. If you want the ability to store a file larger than 4GB, re-format the drive to NTFS, which is what I use for any drive that is shared between Mac and Windows.

     

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