My thumb drive is bad at math

April 5, 2011 10:57 PM

Why won't a 5 gig .avi file fit on my empty 8 gig thumb drive?

My SanDisk Cruzer flash drive (formatted FAT32) shows 8 gigs of unused space. Plugged into my older Windows XP SP3 machine, I can put at least 7.45 gigs of smaller files on it. But when I try to copy a single 5.55 gig AVI file, it says the disk in the destination drive is full.

Doesn't matter if I right-click and Send to F: drive, drag the file, or try to copy from the command line. Zipping it down to 4.7 gigs changed nothing. The thumb drive is fully emptied, checked for disk problems and defragmented. Suggestions? Would formatting the thumb drive NTFS make a difference?

posted by msalt to Computers & Internet (18 answers total)

Best answer: fat32 has a 2GB file size limit. you'll need to format the flash drive to something like ntfs, ext2, hfs, hfs+, ext4 (basically any modern file system) or use rar or 7zip to split the file into <1.99GB chunks.
posted by thewalrus at 10:59 PM on April 5, 2011 [2 favorites]

Response by poster: Wow, quick service! Does it matter what size of allocation unit I format it to? My choices are 512 bytes to 64KB.
posted by msalt at 11:01 PM on April 5, 2011

I think it's a 4GB limit (ie 2^32 bits).
posted by pompomtom at 11:02 PM on April 5, 2011

(and no, changing block size won't change this)
posted by pompomtom at 11:03 PM on April 5, 2011

Would formatting the thumb drive NTFS make a difference?

Yes. It has a higher file size limitation than FAT32.
posted by Blazecock Pileon at 11:07 PM on April 5, 2011

Best answer: If you format it NTFS, you'll only have read-only access on Macs unless you install special drivers or engage in potentially unreliable hacks. This may be no problem for you or it may be a concern, but I wanted you to be aware of the issue.
posted by zachlipton at 11:11 PM on April 5, 2011

Response by poster: I also have the choice of formatting as exFAT (on my Windows 7 laptop.) I can't tell from Wikipedia though if my Windows XP desktop (which has the large file) can support either NTFS or exFAt; it doesn't give me the option of formatting the thumb drive as either.
posted by msalt at 11:19 PM on April 5, 2011

you can install a exfat driver from microsoft on your winxp system
posted by thewalrus at 11:21 PM on April 5, 2011

Response by poster: Wikipedia calls exFAT incompatible though; would my MAC be able to read it? (I'm copying this file to my MAC mini.)
posted by msalt at 11:24 PM on April 5, 2011

Best answer: msalt, Mac OS X 10.6.5 and later includes native support for reading, writing, and creating exFAT partitions.
posted by RichardP at 11:36 PM on April 5, 2011

There are also programs that can split files into smaller chunks, if that would be any help.
posted by Fen at 1:21 AM on April 6, 2011

Windows XP is able to handle NTFS
posted by Triton at 3:06 AM on April 6, 2011

I assume you've ruled out a direct ethernet transfer. If both computers have net access, could you use the file transfer capability of an instant messenger?
posted by TruncatedTiller at 4:31 AM on April 6, 2011

Cross platform file splitter. I used to do this for floppy disks, at least your thumb drive will be faster.
posted by anaelith at 4:44 AM on April 6, 2011

Format as NTFS and copy the file over. The Mac will read it, just not write to it.

Reformat to a different file system afterwards.
posted by Simon_ at 5:07 AM on April 6, 2011

NTFS-3G for Mac is probably the simplest option. I use it; it works well enough.

Seconding the direct ethernet tranfer idea as well.
posted by fifthrider at 5:08 AM on April 6, 2011

You could also keep the current formatting of the drive and just use a AVI Splitter or rar, 7z, zip, etc compression to split the file into smaller volumes.
posted by samsara at 5:28 AM on April 6, 2011

Response by poster: NTFS worked! Thanks so much.
posted by msalt at 7:35 AM on April 6, 2011