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Which format for UFDs?

I’m helping to revise a book on Windows 7 right now. By well-known Windows mavens Brian Knittel and Bob Cowart, it’s to be called Windows 7 in Depth (Pearson, 2009, ISBN: 0789741997). In the course of writing the chapter on hard disks, formats, basic and dynamic volumes and so forth, I was forcibly reminded that there are many different formats that work on USB Flash Drives, aka UFDs. And as is usual for good questions of all kinds the answer to the inevitable question: “Which format should I use on my UF?” start with the famous qualification phrase: “That depends…”

I’ll list the formats that work on UFDs in Windows Vista and Windows 7, and explain why you might use each one in the ensuing explanation (for more great information on this topic see GUIDE: FAT16, FAT32, NTFS, or exFAT on USB Flash Drives? in the forums at the excellent Website):

  • FAT16 (aka simply “FAT;” there used to be a FAT12 format once upon a time, too, but it’s not supported in Vista or Windows 7 although I think these systems can probably still read it) offers the best overall cross-platform support for non-Windows or old Windows OSes, and also delivers the best total performance overall. That said, it’s limited to 2 GB volume size (up to 4GB on some OSes, if a 16 KB cluster size is used), with a maximum file size equal to maximum volume size minus file/directory overhead (usually no more than a few hundred bytes). FAT16 works best for UFDs of 2 GB and smaller.
  • FAT32 also offers good cross-platform support, especially on non-Windows OSes (it won’t work on older DOS versions or Windows versions prior to Win95 SR2), and is not subject to the 2/4 GB size limit (it tops out at 32 GB, more than big enough for all but the largest UFDs on today’s market). It offers only moderate to slower overall performance, however, and supports a maximum file size of 4 GB. FAT32 works pretty well on all but the largest (< 32 GB) UFDs.
  • NTFS supports relatively low cross-platform support, and doesn’t work on non-NT based Windows versions, and not at all on DOS (though the NTFSDOS utility from SysInternals can mitigate this to some extent but only for reading the contents of NTFS volumes). It’s very fast for single files, but doesn’t do as well as FAT16 or FAT32 for write activities involving multiple files. It does support ACL based access controls and works with all kinds of encryption technologies, and is far more secure than FAT (Windows 7 supports a Portable BitLocker implementation that lets you encrypt UFD contents for save storage and transport). You must use the Optimize for Quick Removal option on an NTFS formatted UFD, or risk losing data unless you use the “Safely Remove Hardware” applet to dismount it from your PC. NTFS or exFAT are required for UFDs larger than 32 GB, and work well for those who want to use large UFDs for backups.
  • exFAT, introduced with Vista SP1, is basically FAT64. This supports file and volume sizes of 264-1 (16 exabytes), and volumes to match, and raises the ceiling on maximum file entries per directory as well. Vista can’t use exFAT for ReadyBoost, but Windows 7 can. exFAT currently works only in Vista, Windows Server 2008, and Windows 7, and also suffers from slow write speed on multiple files. NTFS or exFAT are required for UFDs larger than 32 GB, and work well for those who want to use large UFDs for backups.

To format a UFD with any of these file systems, insert it into a Vista or Windows 7 PC, right click the drive icon in Windows Explorer, then select the format entry in the resulting pop-up window, to see a display something like this one (it shows the exFAT format selected in Windows Vista).

exFAT appears as an option in the File System pick list.

exFAT is one option in the File System pick list

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