exFAT or FAT64 File System(To Access USBs more than 32GB)

exFAT or FAT64 (To Access USBs more than 32GB)

exFAT (Extended File Allocation Table, also sometimes referred to as FAT64) is a proprietary, patent-pending file system suited especially for USB flash drives. Developed by Microsoft, it is supported in Windows Embedded CE 6.0, Windows Vista with Service Pack 1, Windows 7 and Windows Server 2008.

exFAT can be used where the NTFS file system is not a feasible solution, due to data structure overhead, or where the file size or directory restrictions of previous versions of the FAT file system are unacceptable.

Windows XP and Windows Server 2003 (both x86 and x64) users can add support for exFAT by installing an update from Microsoft. An experimental, open source Linux kernel module that supports the reading of exFAT files is currently under development. A FUSE-based full-featured implementation is currently in beta status. A proprietary, read/write solution, licensed and derived from the Microsoft exFAT implementation, is available for Android, Linux and other operating systems from Tuxera. A proprietary, full-featured implementation—XCFiles—is available fromDatalight. A full-featured implementation for embedded devices —Rtfs—is available from EBS Embedded software. Two third party open source drivers are available for native DOS.

Mac OS X Snow Leopard added exFAT support in version 10.6.5 on November 10, 2010. OS X 10.6.5 and later can read, write, and create exFAT partitions.

 

ADVANTAGES

The advantages over previous File Allocation Table (FAT) file system versions include:

§  Scalability to large disk sizes: 64 ZiB theoretical max, 512 TiB recommended max, raised from the 16 TiB limit of FAT32 partitions. Note that the built-in Windows 2000/XP/Vista/7 can mount and support FAT32 volumes larger than 32 GB, but cannot create a FAT32 volume larger than 32 GB.

§  Cluster size up to 32 MiB

§  File size limit of 16 EiB (Limited by volume size), raised from close to 4 GiB in FAT32

§  Free space allocation and delete performance improved due to introduction of a free space bitmap

§  Support for access control lists (not supported in Windows Vista SP1)

§  Support for TFAT, a transactional file system standard (optionally WinCE activated function)

§  Provision for OEM-definable parameters to customize the file system for specific device characteristics

§  Support for UTC timestamps (starting with Vista SP2)

§  Timestamp granularity of 10 ms (better than previous FAT versions' 2 s, but worse than NTFS's 100 ns)

 

DISADVANTAGES

The disadvantages compared to previous FAT versions include:

§  Limited or no support outside PC/Mac environment at present — most current consumer electronics, such as televisions and A/V receivers, can only handle previous FAT versions (this may change with the new SDXC cards and Memory Stick XC requiring exFAT (or the use of third party FAT32 formatting tools which can format past the 32 GiB artificial limit and up to 2 TiB, 8 TiB or 16 TiB depending on environment))

§  The standard exFAT format only uses a single file allocation table and free space map. Previous FAT used alternating tables, as this allowed recovery of the file system if the media was ejected during a write (which occurs frequently in practice with removable media). The optional TFAT component adds support for additional backup tables and maps, but may not be supported.

§  Microsoft has not released the official exFAT file specification, and a license from Microsoft is required in order to make and distribute exFAT implementations

§  Windows XP and Windows Server 2003 users must have Service Pack 2 or later and install an update to support exFAT

§  Windows Vista must be Service Pack 1 or later for exFAT support

§  Devices formatted using exFAT cannot be read by any version of Windows prior to Windows XP or by any version of DOS or OS/2 (unless emulated as otherwise).

§  Windows Vista is unable to use exFAT drives for ReadyBoost. Windows 7 removes this limitation, enabling ReadyBoost caches larger than 4 GiB.

§  Subdirectory size is limited to 256 MiB. There is no such limit in FAT32 up to the number of available clusters (that is, up to 2^28 - 11 = 268,435,445).

§  Support for up to 2,796,202 files per subdirectory only,. There is no such limit in FAT32 up to the number of available clusters (that is, up to 2^28 - 11 = 268,435,445).

Note: To Access exFAT in Windows XP required a hot fix, can be downloaded from http://support.microsoft.com/kb/955704

[via techdoor]