(File Allocation Table) The original file system used in DOS, Windows and OS/2. The FAT keeps track of where data are stored on disk. When the disk is high-level formatted, the FAT is recorded twice and contains a table with an entry for each disk cluster.
The directory list, which contains file name, extension, date, etc., points to the FAT entry where the file starts. If a file is larger than one cluster, the first FAT entry points to the next FAT entry where the second cluster of the file is stored and so on to the end of the file. If a cluster becomes damaged, its FAT entry is marked as such and that cluster is not used again. The original 16-bit version of the FAT (FAT16) supported hard disk partitions as small as a floppy disk up to 4GB and files as large as 2GB. The 32-bit version (FAT32) dramatically increased capacity limits. See FAT32
and file system
The FAT Table
The file RESUME.DOC is stored in clusters 0, 2, 3 and 7. The directory entry points to cluster 0 where the file begins. The entry for cluster 0 points to cluster 2 and so on. BUDGET.XLS is stored in clusters 1, 4, 8 and 9.