Source : WordNet®

file allocation table
     n : the prt of a floppy disk or hard disk where information is
         stored about the location of each piece of information on
         the disk (and about the location of unusable areas of the
         disk)

Source : Free On-Line Dictionary of Computing

File Allocation Table
     
         (FAT) The component of an {MS-DOS} or {Windows
        95} {file system} which describes the {files}, {directories},
        and free space on a {hard disk} or {floppy disk}.
     
        A disk is divided into {partitions}.  Under the FAT {file
        system} each partition is divided into {clusters}, each of
        which can be one or more {sectors}, depending on the size of
        the partition.  Each cluster is either allocated to a file or
        directory or it is free (unused).  A directory lists the name,
        size, modification time and starting cluster of each file or
        subdirectory it contains.
     
        At the start of the partition is a table (the FAT) with one
        entry for each cluster.  Each entry gives the number of the
        next cluster in the same file or a 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://www.idg.net/idgframes/english/content.cgi?vc=docid_9-62525.html)}.
        {(http://home.c2i.net/tkjoerne/os/fat.htm)}.
        {(http://www.teleport.com/~brainy/)}.
        {(http://209.67.75.168/hardware/fatgen.htm)}.
        {(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?]
     
        (2000-02-05)