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A FAT file system is a specific type of computer file system architecture and a family of industry-standard file systems utilizing it. The FAT file system is a legacy file system which is simple and robust.〔 It offers good performance even in very light-weight implementations, but cannot deliver the same performance, reliability and scalability as some modern file systems. It is, however, supported for compatibility reasons by nearly all currently developed operating systems for personal computers and many home computers, mobile devices and embedded systems, and thus is a well-suited format for data exchange between computers and devices of almost any type and age from 1981 up to the present. Originally designed in 1977 for use on floppy disks, FAT was soon adapted and used almost universally on hard disks throughout the DOS and Windows 9x eras for two decades. Today, FAT file systems are still commonly found on floppy disks, USB sticks, flash and other solid-state memory cards and modules, and many portable and embedded devices. DCF implements FAT as the standard file system for digital cameras since 1998.〔 FAT is also utilized for the EFI system partition (partition type 0xEF) in the boot stage of EFI-compliant computers. For floppy disks, FAT has been standardized as ECMA-107〔 and ISO/IEC 9293:1994〔 (superseding ISO 9293:1987〔). These standards cover FAT12 and FAT16 with only short 8.3 filename support; long filenames with VFAT are partially patented.〔 == Technical overview == The name of the file system originates from the file system's prominent usage of an index table, the ''File Allocation Table'', statically allocated at the time of formatting. The table contains entries for each ''cluster'', a contiguous area of disk storage. Each entry contains either the number of the next cluster in the file, or else a marker indicating end of file, unused disk space, or special reserved areas of the disk. The ''root directory'' of the disk contains the number of the first cluster of each file in that directory; the operating system can then traverse the FAT table, looking up the cluster number of each successive part of the disk file as a ''cluster chain'' until the end of the file is reached. In much the same way, ''sub-directories'' are implemented as special files containing the ''directory entries'' of their respective files. Originally designed as an 8-bit file system, the maximum number of clusters has been significantly increased as disk drives have evolved, and so the number of bits used to identify each cluster has grown. The successive major versions of the FAT format are named after the number of table element bits: 12 (FAT12), 16 (FAT16), and 32 (FAT32). Except for the original 8-bit FAT precursor, each of these variants is still in use. The FAT standard has also been expanded in other ways while generally preserving backward compatibility with existing software. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Design of the FAT file system」の詳細全文を読む スポンサード リンク
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