special value for "not

allocated" or a special value for "this is the last cluster in the chain". The first few clusters after the FAT contain the root directory.

The FAT file system was originally created for the CP/M[?] operating system where files were catalogued using 8-bit addressing. MS DOS's FAT allows only 8.3 filenames.

With the introduction of MS-DOS 4 an incompatible 16-bit FAT (FAT16) with 32-kilobyte clusters was introduced that allowed partitions of up to 2 gigabytes.

Microsoft later created FAT32 to support partitions larger than two gigabytes and pathnames greater that 256 characters. It also allows more efficient use of disk space since clusters are four kilobytes rather than 32 kilobytes. FAT32 was first available in OEM Service Release 2 of Windows 95 in 1996. It is not fully backward compatible with the 16-bit and 8-bit FATs.

IDG article. http://home.c2i.net/tkjoerne/os/fat.htm. http://teleport.com/~brainy/. http://support.microsoft.com/support/kb/articles/q154/9/97.asp.

Compare: NTFS.

[How big is a FAT? Is the term used outside MS DOS? How long is a FAT16 filename?]

Last updated: 2000-02-05

Nearby terms:

ification time and starting cluster of each file or special value for "not/)}.

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