FAT32

File Allocation Table
FAT
FAT32

   <file system> (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://idg.net/idgframes/english/content.cgi?vc=docid_9-62525.html).
   (http://home.c2i.net/tkjoerne/os/fat.htm).
   (http://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)