OS X Leopard and FAT32

Discussion in 'macOS' started by Dimwhit, Apr 30, 2008.

  1. Dimwhit macrumors 68000

    Dimwhit

    Joined:
    Apr 10, 2007
    #1
    I just got a thumb drive and it came pre-formatted in FAT32. I'll primarily be using this on a Mac, but being able to use it on Windows would be nice, so FAT32 is a good option. My question, though...is there any disadvantage to using a FAT32 thumb drive in OS X as far as speed, reliability, etc.?
     
  2. xUKHCx Administrator emeritus

    xUKHCx

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    Jan 15, 2006
    Location:
    The Kop
    #2
    I've been using fat32 thumb drives for about 5 years with both OSX and windows and never had a problem.
     
  3. richard.mac macrumors 603

    richard.mac

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    #3
    nope but there may be some limitations that you may never encounter look here. its just that FAT32 has a 4GB file limit so most thumb drives and even iPods under 4GB are formatted as FAT32 so they are multi-OS.
     
  4. Dimwhit thread starter macrumors 68000

    Dimwhit

    Joined:
    Apr 10, 2007
    #4
    Cool, thanks. Just wanted to make sure I wasn't missing anything.
     
  5. xgman macrumors 601

    xgman

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    Aug 6, 2007
    #5
    huh? I have a 8gb fat32 thumbdrive and both windows and lwopard see all 8 gugs fine.
     
  6. Dimwhit thread starter macrumors 68000

    Dimwhit

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    Apr 10, 2007
    #6
    He means individual file size. You couldn't put, for example, a 5GB movie file on that drive if it's FAT32.
     
  7. chicken123 macrumors newbie

    Joined:
    Mar 2, 2008
    #7
    file size with FAT32

    I have a fat32 formatted drive from Lacie. I have a 29.8G file which OSX read and write without any problem. I am confused to see people write about a limitation of FAT32 file to 4G??:confused:
     
  8. Dimwhit thread starter macrumors 68000

    Dimwhit

    Joined:
    Apr 10, 2007
    #8
    Who knows...I'm just basing it on what I hear. But what kind of file do you have? If it's an iMovie file, or something similar, that would probably bypass it, since it's really just a package with many different files in it.
     
  9. chicken123 macrumors newbie

    Joined:
    Mar 2, 2008
    #9
    I run VMware fusion and Windows XP. All the Windows installation is in a single file (29G). I can copy this single file to another Mac and using the FAT32 disc drive from Lacie. The other Mac seems to read the file OK and run Windows using VMFusion successfully.:)
     
  10. Knolly macrumors 6502a

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    Jul 22, 2007
    #10
    I have no idea how you are accomplishing that because I assure you it should be impossible by every technical explanation of the FAT32 file system...
     
  11. chicken123 macrumors newbie

    Joined:
    Mar 2, 2008
    #11
    I am confused too. Can anybody out there explain how Mac OSX can read and write a file larger than 4G on a FAT32 formatted disc? I am very interested to know. I have search the net for an answer. Most seems to say the same thing that FAT32 has a limit of 4G but no want mention that maybe Mac OSX can address a file greater that 4G on a FAT32 formatted disc. Confused???:confused:
     
  12. chscag macrumors 68000

    Joined:
    Feb 17, 2008
    Location:
    Fort Worth, Texas
    #12
    The simple answer is it CAN NOT. FAT-32 has a maximum limit of ~4Gb per file because of its internal cluster structure. Most external drives purchased nowadays are large and will most likely be pre-formatted as NTFS.

    Even Microsoft's Vista will not install to FAT-32, it will only install to NTFS.

    For a better explanation and understanding of FAT-32 and why it's limited to a maximum file size of ~4 Gb, see the Microsoft Knowledge Base at their web site. The operating system does not matter, the limitation is still there.

    Regards.
     
  13. chicken123 macrumors newbie

    Joined:
    Mar 2, 2008
    #13
    I enclosed attachments 2 screen shots of the info of my portable disc drive from Lacie. Picture 1 shows that it is formatted in MSDOS FAT32 and picture 2 shows that there is a single file showing a 29G file. Please believe me. I have read and written into this 29G file with no problem. I have copied this file into another Mac and used the file without any problem. This is not theory but practice!!
     

    Attached Files:

  14. Mal macrumors 603

    Mal

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    Jan 6, 2002
    Location:
    Orlando
    #14
    I believe that the Virtual Machine files from VMWare, which is what you have, are a form of package file like he was referring to. In other words, it's a wrapper for many other files (which is logical).

    It's also possible that the issue has been resolved.

    jW
     
  15. chicken123 macrumors newbie

    Joined:
    Mar 2, 2008
    #15
    Mal,

    You may right about the "package file". It would be interesting for somebody to try a large video file greater than 4G and see if it works.
     
  16. tshort macrumors regular

    Joined:
    Jul 20, 2007
    #16
    A VMWare machine is a package or bundle, in other words, a DIRECTORY. If you use terminal, you will see that you can cd in the bundle and traverse it. It is not a single file. If you look at that Lacie drive under Windows, you will see it is a directory!

    The FAT32 limitation of 4GB files is due to the fact that 4GB is the largest 32-bit number, and the length of the file in the directory entry is 32-bits. In theory, a file could take up every single cluster in the partition, but you wouldn't know how big it really was.
     
  17. chicken123 macrumors newbie

    Joined:
    Mar 2, 2008
    #17
    Tshort,

    You are absolutely right. I tried to look into the "directory" as you have suggested. It is indeed a package made up of many files each not exceeding 4G. I am happy now and understand it. Thanks very much.:)
     

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