File Allocation Table

File Allocation Table

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The File Allocation Table (FAT) is a file system that was initially introduced by Microsoft in 1977 and was widely used in DOS (Disk Operating System) and early versions of Windows. It’s a simple file system designed for small disks and simple folder structures.

The “File Allocation Table” is a data structure that the operating system uses to locate files on a disk. The FAT keeps track of each file’s starting location and all the subsequent parts of the file on the disk. The FAT is also used to manage and allocate space on the disk; when a file is deleted, its space in the FAT is marked as available for re-use.

There are different versions of FAT, like FAT12, FAT16, and FAT32. The numbers refer to the size of the entries in the allocation table. For instance, FAT12 uses 12 bits for each entry, while FAT32 uses 32 bits. The larger the number, the more disk space the FAT version can manage. For instance, FAT32 can handle disk sizes up to 2 terabytes.

While FAT file systems are relatively simple and widely compatible with many operating systems, they lack many of the features and efficiencies of modern file systems, like the NTFS (New Technology File System) used in more recent versions of Windows, or ext4 used in Linux. For instance, FAT32 doesn’t support file permissions or file sizes larger than 4GB.

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