External HDD formatting

in macOS edited January 2014
I have a G4 iBook running Tiger 10.4.3 and I have recently purchased a 200 Gig HDD and USB 2 external caddy. After setting up the hardware I powered it up and plugged it into my Mac. It was detected and I opened up Disk Utility to set up the drive. I am aware of the size limitations for Fat32 but want to be able to use the drive on friends Windows systems. So I went into Partition and created a MS-DOS partition which used the entire drive, I then went to Erase and formatted the drive to Fat32 successfully. The drive is now accessible, displays as the entire disk and I can read and write to it.

I thought that this was not possible, that Fat32 only had a maximum partition size of 32 GB. I did find the following in the MS KB -

'You cannot format a volume larger than 32 gigabytes (GB) in size using the FAT32 file system during the Windows XP installation process. Windows XP can mount and support FAT32 volumes larger than 32 GB (subject to the other limits), but you cannot create a FAT32 volume larger than 32 GB by using the Format tool during Setup. If you need to format a volume that is larger than 32 GB, use the NTFS file system to format it. Another option is to start from a Microsoft Windows 98 or Microsoft Windows Millennium Edition (Me) Startup disk and use the Format tool included on the disk.'

This sort of states that it's the limitation of the XP format and that XP can still mount Fat32 volumes larger than 32 GB.

Can anyone explain this to me ? I am concerned as I don't want to lose data on this drive and if I need to I will format it to HFS, but would love to have the cross platform accessibility.


  • Reply 1 of 3
    Dunno if this is still of any use, I was digging through the old messages but the explanation is as follows...

    In theory you can format up to 8 terrabytes (or something) with FAT32, although 2 terrabytes is the 'usable' maximum due to the allocation table size.

    The 32Gb thing is limited to WinXP to try and make users move away from FAT32 and towards NTFS, you can create any size FAT32 partition in win98 etc AND XP will read a bigger-than-32Gb FAT32 partition, just not create one.
  • Reply 2 of 3

    Thanks for your reply, I realised after I had finished the post and then read some more that I had sort of answered my own question :-)

    Have tried the external hard drive on a mate's XP system and had no issues with it.

    Cheers for you reply, I will have to read more and trust my own conclusion in the future :-)
  • Reply 3 of 3
    There's one more limitation: any invididual file bigger in size than 4GB will not be able to reside on your FAT32 partition. That's a limitation in that filesystem.

    Files smaller than or up to 4GB are fine, anything bigger is a no-no. Of course, files like that are rare, but let's say you have an .ISO of some sorts that is, say, 6GB in size - it won't be able to reside in that hard drive.
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