The rest of the space allocated to the filesystem is occupied by storage blocks, also called data blocks. The size of these storage blocks is determined at the time a filesystem is created and can be 2048, 4096, or 8192 bytes. Because of these large block sizes and the potential for waste with small files, ufs also has a subdivision of a block called a ``fragment''. When a filesystem is created, the fragment size must match or be smaller than the block size: you can set it to 512, 1024, 2048, or 4096 bytes. Fragments of 1024 bytes are the most commonly employed. For a regular file, the storage blocks contain the contents of the file. For a directory, the storage blocks contain entries that give the inode number and the filename. ufs filenames can be up to 255 bytes long. Each entry represents a file or subdirectory that is a member of the directory.