Fully qualified file name

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The term fully qualified file name means a file on a computer whose exact name is completely specified such that it is unambiguous and cannot be mistaken for any other file on that system. It is somewhat equivalent on the Internet to a URL specifying the full name of the computer and the entire name of a particular document as a file. The alternative is an unqualified file name or a partially qualified file name.

  • On Unix-style systems, including MS-DOS and Microsoft Windows, the name "sample" refers to a file in the current directory named "sample". If the current directory is changed, then the file referred to by the name "sample" is different. If you start the filename with "/" indicating the root directory as in "/Users/Name/sample", then on Unix this is a fully qualified file name. On MS-DOS this is still relative to the root directory of the current disk, to get a fully qualified name, you need to prefix the drive name, as in "C:/Users/Name/sample", then "C:" specifies the C drive. (Windows also accepts a "\" but this makes no difference to the file being named).
  • Again on Unix and MS-DOS and Microsoft Windows, some programs such as the command-line shell will search a path for a file. Inserting some slashes, as in "./name", will stop the searching of the path, thus this is a partially-qualified name, but not a fully-qualified name as it still depends on the current directory. A fully-qualified name, because it contains slashes, will always stop a path search.
  • On the mainframe operating system MUSIC/SP, if one asks for the file name "X", one is making an unqualified reference either to the file X in the user's library, or to the file X in the common library if the user does not have a file named X and one does exist in the common library. If, however, one were to refer to "*COM:X" one is using a fully qualified file name reference to the file X in the common library even if they have a different file named X in their library. Similarly, a reference to "*USR:X" would mean the file in their own library, and "MA45:X" would be a fully qualified file name referring to the specific file X in the library of user MA45.
  • On the Univac 90/60 mainframe operating system VS/9, specifying a file "X" could mean either the file X in the account of that user, or could mean the file X in the library of the system manager, $TSOS. However, specifying "$S0103.X" would be a fully qualified file name.
  • This term can also include the case where one prefixes a fully qualified file name with a specific computer name as a prefix to a file name (where the particular system permits referencing a file on another system), so long as the exact name is unambiguous.

See Also: Fully qualified domain name.