Pathname conventions are the rules used to form names that uniquely identify files in a given file system. Although each file system can have specific rules about how individual components in a directory or filename are formed, all file systems follow the same general conventions for combining components. For example, although the FAT file system requires that file and directory names have the 8.3 filename format, and LongFileNames ( LFN ) FAT file system allows names to be any length, both file systems use the backslash (\) character to separate directory names and the filename when forming a path.