FAT file system was supported by almost all personal computer operating systems because the computer performance was limited and not complicated at that time. This feature makes it an ideal file system for floppy disks and memory cards, and is also suitable for data exchange in different operating systems. Now generally speaking, fat refers to FAT32.
Extended data
The FAT file system consists of four different parts.
Reserved sector, located at the beginning. The first reserved sector is the boot sector (partition startup record). It includes an area called the basic input and output parameter block, which usually contains the startup call code of the operating system. The total number of reserved sectors is recorded in the parameters of the boot sector. In DOS and OS/2, the operating system structure called the driver parameter block can access the important information in the boot sector.
Fat area. It contains two file allocation tables for system redundancy. Although it is rarely used, even disk repair tools are rarely used. It is a mapping table of partition information, indicating how clusters are stored.
Root zone. It is a directory table that stores file and directory information in the root directory. Under FAT32, it can exist anywhere in the partition, but in earlier versions, it was always after the FAT area.
Data area. This is the actual file and directory data storage area, which occupies most of the partition. Just increase the number of file links in FAT, and you can increase the file size and the number of subdirectories at will. However, it should be noted that each cluster can only be occupied by one file, so if there is a file with the size of 1KB in a cluster with the size of 32KB, the space of 3 1KB is wasted.
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