Directories Directories provide a hierarchical structure to the file system and link file and subdirectory names to i-nodes. There is no limit on the depth of nested directories.
Processes can read directories as regular files.
However, the kernel reserves the right to write directories. For this reason, directories are created and maintained by a set of subroutines unique to them. The file name field is null-terminated and padded to 4 bytes. File names can be up to 255 bytes long. Directory entries are variable-length to allow file names the greatest flexibility.