File Allocation Table (FAT) is an area on the hard disk or floppy disk containing information of every file stored and unallocated spaces on the disk and first developed for MS-DOS. Most of the PCs operating system support FAT file system hence, external devices like memory cards, SD, pen drives etc., supports FAT file system. FAT12 is the oldest type of FAT file system. FAT12 indicates that the size of each entry in the file allocation table of a disk is 12 bits. FAT12 is therefore suitable for small volumes (floppy disk) having size of 16MB or less. It has a cluster size ranging from 0.5KB to 4KB.
The size of the FAT determines the number of clusters the disk volume can contain. FAT12 can store 4086 clusters (2 12- few clusters, approx). Floppy disks have FAT12 file system. The hierarchy from top level to bottom is as follows:
Disk → Partition (one or more) → Clusters (one or more) → Sectors (one or more, depending on size)
The entry provides the number of the next cluster. FAT is something like table of contents in a book. If the file allocation table is lost or damaged, then reading the disk becomes a problem.
Regions of FAT12 disk or disk organization
Disadvantages of FAT12
In order to overcome the limitations of the previous FAT file systems, FAT 32 was created. With FAT 32 file system you can format external drives or your computer's hard disk as well as partitions. Due to accidental formatting data from logical drives can be lost. To recover FAT32 partition or external disk drive, use the best recovery utility.