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I'm trying to copy a 5.3 GB file from hard disk to a USB 3.0 SanDisk 16 GB USB key. I've tried this both from OS X as well as from Linux. In both cases the file is partially copied and then the operation fails. On OS X it fails with a message like "file too large". I had to use the split command to split the file into several 100MB chunks and then copy the directory containing them to the USB key in order to copy the file.

Then, on Linux I reassembled the files with the cat command into a single file, sending the output to the computer's hard drive. However, when I tried to reassemble the split files into one file with the cat command and sent the output to the USB key, the USB key still did not accept the resulting file, which again, was too large, and complained with the error message

"cat: write error: Protocol error".

When I inspected the successful output with:

$ ls -l --block-size=M MyFileName

the file size was exactly:

4096M (that is, 4 GB).

This seems like a limitation tied to the USB key's default filesystem with which it was formatted prior to being sold.

When I examine its filesystem under Windows 7 by right-clicking on the USB disk and inspecting its properties I can see that the filesystem is a FAT32 filesystem.

Can I somehow, starting from Windows, format the USB key so that it uses a filesystem which will accept my 5.3 GB file, and can at the same time be read from and written to from all of OS X, Linux, and Windows 7? What filesystem should I format the USB key to in order to achieve this very purpose?

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    FAT32 will definitely refuse a 5.3gb file. I don't know what file systems your other OSes support so I don't know if NTFS will be acceptable or not. Nov 17, 2013 at 22:39

1 Answer 1

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No perfect solution, but your top candidates are NTFS and exFAT:

  • Windows (recent versions) will read and write both, natively
  • OS X will read NTFS and read/write exFAT
  • Linux will read NTFS (kernel support)

Third-party drivers can fill in the missing (non-Windows) gaps; some Linux distros include them. If your usage is actually just reading from Windows, then NTFS will work out of the box. If you're primarily OS X and not Linux, then exFAT would be better.

Either one can be formatted right in the Windows (File) Explorer GUI on the desktop.

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  • Thank you. When I right click on my USB pen drive I can see an option to format it as exFAT on Windows 7. I've seen there are various ways to enable support for exFAT on Linux on this page: en.wikipedia.org/wiki/Exfat . Regards. Nov 18, 2013 at 9:42

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