A Hierarchical File System

A file system contains both subdirectories and files.  A subdirectory

is a file that may contain other files and subdiretories.

                                    the root   

                                    directory  

                                         /     

                                         |

                -----------------------------------------------

                |                        |                    |

          subdirectory/            subdirectory/             file

                |                        |                      

         ---------------          ---------------

         |             |          |             |

   subdirectory/      file       file          file

         |                                                         

    ------------

    |          | 

   file        file