Microsoft originally developed FAT (File Allocation Table) as a simple file system for diskettes and then hard disks. FAT originally ran on very early, very small microcomputers, e.g., IBM PCs with 256 KB of memory. Windows, Mac OS, Linux, and many Unix-like systems also use FAT as a file interchange format.
FAT was designed for magnetic disks, but today supports Flash memory and other storage devices.
µC/FS is an implementation of FAT that supports FAT12, FAT16, and FAT32. By default, µC/FS supports only short (8.3) file names. To enable long file names (LFNs), you must set a configuration switch. By setting this switch, you agree to contact Microsoft to obtain a license to use LFNs.