File Allocation Table (FAT)

A special file located on a disk containing information about the sizes of files stored on the disk and which clusters contain which files. It can also keep track of bad spots on a disk so they are not used. Think of it as a sort of roadmap to the files on a disk. Drives must first read the roadmap before they can find any of the information stored, or before they can know where to store any new information. There are a number of different types (formats) of file allocation tables in use that have different capabilities in terms of how (and how much) data can be stored on a drive partition. See also “FAT,” “FAT-32,” and “exFAT.”