Fully Qualified File Name - Filenames and Paths

Filenames and Paths

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, 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. In DOS, this is still relative to the root directory of the current disk, to get a fully qualified file name, one must prefix the file name with the drive letter and a colon, as in "C:\Users\Name\sample", where "C:" specifies the "C" drive.
• Also on the above systems, some programs such as the command-line shell will search a path for a file. Inserting a leading (back)slash, as in "./name", will stop the searching of the path. 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 (back)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 RSTS/E operating system on the PDP-11 minicomputer, specifying a file "X.X" would refer to a file in one's own directory. Referring to "$X.X" would be referring to the file "X.X" but to fully qualify the file name, one would have to indicate the device, so "SY:MYFILE.TXT", "SY:$X.X", or "SY:X.X" (the last two examples meaning the same thing) would be a fully qualified file name under RSTS/E.
• 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.