Hierarchical file system
A hierarchical file system is how drives, folders, and files are displayed on an operating system. In a hierarchical file system, the drives, folders, and files are displayed in groups, which allows the user to see only the files they're interested in seeing. For example, in the picture the Windows directory (Windows\) folder hierarchy that contains the System32, Tasks, and Web folders. Each of these folders could have hundreds of their own files, but unless they are opened the files are not displayed.
In GUI operating systems such as Microsoft Windows, the user expands a drive or folder to see its contents by double-clicking the icon. Once the file or program is located, double-click the icon to open the file or execute the program.
In a non GUI operating system, such as MS-DOS or the Windows command line, the drive and directories are listed as text. For example, if you were on the C: drive and in the Windows spool directory, the MS-DOS path may look like the following example.