macOS, however, uses filename suffixes, as well as type and creator codes, as a consequence of being derived from the UNIX-like NeXTSTEP operating system. Additionally, a creator code was specified to determine which application would be launched when the file's icon was double-clicked. The classic Mac OS disposed of filename-based extension metadata entirely it used, instead, a distinct file type code to identify the file format. The assumption was still that any extension represented a single file type there was an unambiguous mapping between extension and icon. Microsoft Windows allowed multiple applications to be associated with a given extension, and different actions were available for selecting the required application, such as a context menu offering a choice between viewing, editing or printing the file. With the advent of graphical user interfaces, the issue of file management and interface behavior arose. The VFAT, NTFS, and ReFS file systems for Windows also do not separate the extension metadata from the rest of the file name, and allow multiple extensions. This model generally requires the full filename to be provided in commands, whereas the metadata approach often allows the extension to be omitted. It is more common, especially in binary files, for the file to contain internal or external metadata describing its contents. Programs transforming or creating files may add the appropriate extension to names inferred from input file names (unless explicitly given an output file name), but programs reading files usually ignore the information it is mostly intended for the human user. gz indicates that the tar archive file is compressed with gzip). tar indicates that the file is a tar archive of one or more files, and the. More than one extension usually represents nested transformations, such as (the. Sometimes it is said to have more than one extension, although terminology varies in this regard, and most authors define extension in a way that does not allow more than one in the same file name. The dot character is just another character in the main filename. Some file systems implement filename extensions as a feature of the file system itself and may limit the length and format of the extension, while others treat filename extensions as part of the filename without special distinction.įilesystems for UNIX-like operating systems do not separate the extension metadata from the rest of the file name. Other extension formats include dashes and/or underscores on early versions of Linux and some versions of IBM AIX. A filename extension is typically delimited from the rest of the filename with a full stop (period), but in some systems it is separated with spaces. The extension indicates a characteristic of the file contents or its intended use.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |