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What is FAT12?

Updated on Oct 22, 2018 by Daisy to Resource

Summary

What is FAT12 file system? File Allocation Table (FAT) is a file system that was developed for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows ME. Read details.

File Allocation Table (FAT) is a file system that was developed for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows ME. The FAT file system is considered relatively uncomplicated, and because of that, it is a popular format for floppy disks; moreover, it is supported by virtually all existing operating systems for personal computers, and because of that, it is often used to share data between several operating systems booting on the same computer (a multi-boot environment). It is also used on solid-state memory cards and other similar devices. It has a serious drawback in that when files are deleted and new files written to the media, the files can become scattered over the entire media making reading and writing a slow process. De-fragmentation is one solution to this, but is often a lengthy process in itself and has to be repeated regularly to keep the FAT file system clean.

FAT is also called 12-bit FAT, the file allocation table (FAT) for a floppy disk. The location of files on a floppy disk is listed in a one-column table in the FAT. Because the width of each entry in a floppy disk column is 12 bits, the FAT is called FAT12. As a file system for floppy disks, it had a number of limitations: no support for hierarchical directories, cluster addresses were "only" 12-bits long (which made the code manipulating the FAT a bit tricky) and the disk size was stored as a 16-bit count of sectors, which limited the size to 32MB.

Please see: FAT16 | VFAT | FAT32 | NTFS/NTFS5 | EXT | EXT2 | EXT3 | EXT4 | SWAP | exFAT | ReFS