The FAT32 file system is already widely used in many computers, however it doesn’t support partition bigger than 2 TiB and files larger than 4 GiB. Fortunately, a replacement for FAT32, is coming: the exFAT. Microsoft has chosen this file system as the basis for its future products and Mac OS X already supports exFAT in its recent releases. The exFAT can be considered as “the FAT64”, which offers better support on larger storage size.

Space management, the number of sub-directories and supported files size is improved in exFAT, including higher number of files in each directory from 65,536 in FAT32 to 2,796,202 in exFAT. Better yet, formatted capacity is slightly higher in exFAT than in FAT32. For example in a 4 GB USB flash drive (with the original size of 4023 MB), 4014 MB is usable when formatted with FAT32, 3997 MB in HFS+, 3974 MB in NTFS and 4022 MB in exFAT. The gain could be small, but it is there. Be careful though: the default cluster size is 32 KB, implying higher loss when working with very small files.

ExFAT is well optimized for flash drives, like USB drives, memory cards and SSDs, 32 KB clusters are more suitable for chips with large blocks and limits the wear of the chips. Finally, access permissions and date management in file properties is more efficient and a finer time granularity (exFAT has an accuracy of 10 ms, FAT32 is limited to two seconds). Main problems of exFAT, is related to its licensing policy with Microsoft exFAT and it is not exactly an open source technology. It requires royalties payment to Microsoft for integration into an operating system (mobile devices such as digital cameras, do not require royalties).

Windows 7

The newest OS from the Redmond is obviously compatible with exFAT, and all of its functions are supported. Windows 7 in 32- or 64-bit version is fully compatible with exFAT and it can even be used with the ReadyBoost feature, which overcomes the limitation of 4 GiB file size in USB drives.

Windows Vista

Windows Vista is compatible exFAT, but only from Service Pack 1. Additionally, certain features are not available (access permission and date management). Unlike Windows 7, in Vista, exFAT can’t be used in conjunction with ReadyBoost.

Windows XP

There is no direct support for exFAT in Windows XP. But a driver is available on the Microsoft site and it requires Service Pack 2 for Windows XP.

For older Windows systems, there is no official support and it is supported in Windows Server 2008 version and with a driver in Windows Server 2003.

Snow Leopard

Mac OS X support for exFAT is already present in version 10.6.4 (15 June 2010) but only in Mac models with a SDXC card reader. Latest Mac mini and iMac are compatible with exFAT.

Linux

On Linux system, there is still no direct support for this file system. Obviously, exFAT requires royalty payment and it is not free, which make integration unlikely. Currently, there are several solutions, but they are not practical or free. The first is integration in the kernel, but it is in read-only (and still at alpha version). The second is through the implementation of FUSE and it is still in beta version. The last is the use of paid, proprietary drivers, which is much more reliable.

When tested in Windows 7, exFAT seems to have equal performance to the FAT32 while the NTFS is a bit faster. Will exFAT replace FAT32? Perhaps, when the entire computer market has transitioned completely to Windows 7 or above. For consumers, performance gain is insignificant but most importantly, they won’t be hampered annoying limitations of FAT32.

The problem is exFAT is not yet readily available everywhere as FAT32 is used on 99% of machines on the market, exFAT requires more modern computer with latest OSs (Windows 7 and recent versions of Snow Leopard), while consumer devices such as cameras won’t support this file system.

In the end, exFAT is interesting but won’t replace FAT32 just yet. And given the way things are progressing, FAT32 is likely to remain be used for (a very) long time.