The device would search for the filename by reading data sequentially, ignoring any non-matching filenames. HFS Plus uses Unicode to store filenames. Wildcards are accepted in place of filenames or filetypes. Thus, whitespace and other characters in filenames and program arguments are handled cleanly. Some filesystems restrict the length of filenames. A solution was to adopt Unicode as the encoding for filenames. GNU/Linux provides a VFAT filesystem driver to work with FAT volumes with VFAT long filenames. It allowed mixed-case Unicode long filenames (LFNs), in addition to classic "8.3" names. Some filesystems prohibit the use of lower case letters in filenames altogether. Many file system utilities prohibit control characters from appearing in filenames. In computer programming, glob patterns specify sets of filenames with wildcard characters. On NTFS filesystems the generation of 8.3 filenames can be turned off. The 7z format provides the option to encrypt the filenames of a 7z archive. The Maildir standard can only be implemented on systems that accept colons in filenames. Most file systems have restrictions on the length of filenames.