Editing File system (section)

====FAT====
{{Main|File Allocation Table}}

The family of [[File Allocation Table|FAT]] file systems is supported by almost all operating systems for personal computers, including all versions of [[Microsoft Windows|Windows]] and [[MS-DOS]]/[[PC&nbsp;DOS]], [[OS/2]], and [[DR-DOS]]. (PC&nbsp;DOS is an OEM version of MS-DOS, MS-DOS was originally based on [[Seattle Computer Products|SCP]]'s [[86-DOS]]. DR-DOS was based on [[Digital Research]]'s [[Concurrent DOS]], a successor of [[CP/M-86]].) The FAT file systems are therefore well-suited as a universal exchange format between computers and devices of most any type and age.

The FAT file system traces its roots back to an (incompatible) 8-bit FAT precursor in [[Standalone Disk BASIC]] and the short-lived [[MIDAS (operating system)|MDOS/MIDAS]] project.{{Citation needed|date=September 2012}}

Over the years, the file system has been expanded from [[FAT12]] to [[FAT16]] and [[FAT32]]. Various features have been added to the file system including [[subdirectory|subdirectories]], [[codepage]] support, [[extended attribute]]s, and [[long filenames]]. Third parties such as Digital Research have incorporated optional support for deletion tracking, and volume/directory/file-based multi-user security schemes to support file and directory passwords and permissions such as read/write/execute/delete access rights. Most of these extensions are not supported by Windows.

The FAT12 and FAT16 file systems had a limit on the number of entries in the [[root directory]] of the file system and had restrictions on the maximum size of FAT-formatted disks or [[partition (computing)|partitions]].

FAT32 addresses the limitations in FAT12 and FAT16, except for the file size limit of close to 4&nbsp;GB, but it remains limited compared to NTFS.

FAT12, FAT16 and FAT32 also have a limit of eight characters for the file name, and three characters for the extension (such as [[.exe]]). This is commonly referred to as the [[8.3 filename]] limit. [[VFAT]], an optional extension to FAT12, FAT16 and FAT32, introduced in [[Windows 95]] and [[Windows NT 3.5]], allowed long file names ([[Long File Name|LFN]]) to be stored in the FAT file system in a backwards compatible fashion.