Transaction-Safe FAT File System: Difference between revisions

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'''A transactionTransaction-safeSafe FAT File System''' ('''TFAT''') fileand system'''Transaction-Safe isExtended aFAT File System''' ('''TexFAT''') refer to two [[file system]]s used in [[Microsoft]] designedproducts to provide transaction-safety for data stored on a disk. TFATThe requiresgoal ais hardware-specificto driverreduce designedthe forrisk theof data loss in typecases of mediapower onloss whichor unexpected removal of the TFATdrive. The latter problem has become more common with the spread of volume[[USB]] residesdrives.

== {{anchor|FAT0|FAT1|TFAT12|TFAT16|TFAT32}}TFAT ==

In addition, TFAT only can be implemented in a system using the extended FAT ([[exFAT]]) file system. TFAT supported by an exFAT file system is also known as [[TexFAT]].

The ''Transaction-Safe FAT File System'' (TFAT) of the '''TFAT12''', '''TFAT16''' and '''TFAT32''' file systems is a driver layer modification to the original [[File Allocation Table|FAT]] file systems [[FAT12]], [[FAT16]] and [[FAT32]] maintaining two copies (FAT&nbsp;0 and FAT&nbsp;1) of the file allocation table instead of two identical ones. While performing a drive operation, changes would be made to FAT&nbsp;1. When the operation is complete, the FAT&nbsp;1 table would be copied to FAT&nbsp;0, updating the stable view of the file system.<ref name=MSTFAT>{{cite web

*| [httpurl=https://msdn.microsoft.com/en-us/library/aa915463.aspx TFAT Overview]

| title=TFAT Overview

| date=2015-11-17

| publisher=[[Microsoft Developer Network]]

| access-date=2019-12-05}}</ref>

{{Details|Design of the FAT file system#CLUST 1}}

== TexFAT ==

The ''Transaction-Safe Extended FAT File System'' (TexFAT), TexFAT provides similar functionality to TFAT using the [[exFAT]] file system as the base file system instead of FAT. Introduced with [[Windows Embedded CE 6.0]], it is sometimes referred to as ''TFAT'' as well, which can lead to confusion with the original TFAT described above.<ref name=MSTexFAT>{{cite web

*| [httpurl=https://msdn.microsoft.com/en-us/library/aa911939cc907927.aspx Transaction-Safe FAT File System]

| title=Transaction-Safe Extended FAT File System

| date=2010-03-18

| publisher=Microsoft Developer Network

| access-date=2019-12-05}}</ref>

The use of exFAT as the underlying file system allows for larger files and larger partitions. TexFAT requires a hardware-specific driver designed for the type of media on which the TexFAT volume resides.<ref name=MSTexFAT /> TexFAT is not supported by desktop/server versions of Windows.

== Limitations ==

Due to the lack of support in desktop [[operating system]]s, neither TFAT nor TexFAT are recommended for removable media. While the desktop OS could still read the drive, it could not use the transaction-safe features, so unexpected removal or a power outage could lead to data loss. In addition, directories created under the desktop OS may not be transaction-safe even if the drive is later attached to a TFAT/TexFAT aware operating system.<ref name=MSTFAT />

== See also ==

* [[Design of the FAT file system]]

* [[Novell Transaction Tracking System]]

== References ==

{{Reflist}}

== Further reading ==

* {{cite conference

| title=Design Methodologies of Transaction-Safe Cluster Allocations in TFAT File System for Embedded Storage Devices

| publisher=[[IEEE]]

| first1=Keshava

| last1=Munegowda

| first2=G.T.

| last2=Raju

| first3=Veera Manikandan

| last3=Raju

| first4=T.N.

| last4=Manjunath

| date=December 2014

| conference=2014 International Conference on Information Technology

| doi=10.1109/ICIT.2014.22}}

* {{cite conference

| title=Characterization of Transaction-Safe Cluster Allocation Strategies of TexFAT File System for Embedded Storage Devices

| first1=Keshava

| last1=Munegowda

| first2=G.T.

| last2=Raju

| first3=Veera Manikandan

| last3=Raju

| first4=T.N.

| last4=Manjunath

| date=2014-12-11

| conference=Computational Intelligence in Data Mining

| doi=10.1007/978-81-322-2205-7_47}}

{{File systems}}

==External links==

* [http://msdn.microsoft.com/en-us/library/aa911939.aspx Transaction-Safe FAT File System]

* [http://msdn.microsoft.com/en-us/library/aa915463.aspx TFAT Overview]

[[Category:Windows disk file systems]]

[[Category:Flash file systems]]

[[zhCategory:TFATWindows CE]]