A file directory (or folder) is a special-purpose file that records information about other files and possibly other directories. The directory consists of a set of entries, each containing the name of a file followed by other information necessary to access the file.
Directories and folders are technically different, especially under Windows. Windows provides other information about folders, and allows them to be used as special directories for things like pictures, videos, music, etc. Here different meta data is used and stored to make working with those files easier/better. All of this is transparent to the end user.
A tree-structured directory hierarchy is a collection of directories organized such that (1) every directory points to zero or more files or directories at the next lower level, and (2) every file and directory except the root is pointed to by exactly one parent directory at the next higher level.
The root of a tree-structured directory hierarchy is the highest level directory, which does not have a parent directory. This is why the base directory of your drive is called the “root directory”.
An absolute path name of a file, uniquely identified by an internal ID, f, is the concatenation of the directory and file names leading from the root to the file. The individual names are separated by an agreed-upon delimiter, typically a forward slash or a backslash.
A relative path name is a concatenation of file names starting with the current directory. You can use “..” + the file separator to go a parent level.
In addition to the commands that can be performed on files, you can also change (the current directory), list (the directory’s contents), and find (a file within a directory).
Directed Acyclic Directory Structure
The main drawback of a tree-structured directory hierarchy is that file sharing is asymmetric. Only one directory can be the parent of any file or another directory.
A directed acyclic directory hierarchy organizes directories such that any directory at a given level may point to zero or more files/directories at lower levels and also permits any file or directory to have more than one parent directory. These links to other locations are known as a symbolic links.
A reference counter is used to keep track of how many places a file is referenced.
This can be more difficult to manage.
File Directories was originally found on Access 2 Learn
