A Hierarchical File System (HFS) is used to arrange and organize digital information on a computer through a series of folders and sub-folders. The largest unit that contains all of the data is typically referred to as the" root," and it can be visualized as the top of a menu or as the left-most entry in a file path. Within this root are then contained one or more folders that can also have additional information within them. At the bottom of a hierarchical file system are individual units of information that can be accessed and read through navigating the structure of the hierarchy.
The term "Hierarchical File System" can be used to refer to a specific format, which was used in an Operating System (OS) developed by Apple Computers®. It is often used in a general context, however, to indicate any type of format that uses this basic structure. The purpose of a hierarchical file system is to organize information in a way that is effective for a computer and fairly intuitive for a user.
Previous methods of arrangement often included all information within a single layer. This meant that when a computer searched through or loaded data, everything stored upon it had to be included. As hard drives and other storage devices increased in size, this become increasingly problematic for both the computer and user. To counteract this, the hierarchical file system was developed, which organized information in layers or directories that could then be more efficiently navigated.
If a hierarchical file system is visualized from the top down, then the top-most layer is the root directory, in which all other data is contained. Within this there are typically numerous folders or sub-directories, which in turn contain additional sub-folders and files. At the very bottom of this visual tree are the different pieces of data that are accessed and used by a computer to retrieve information. This entire structure is essentially a branching network of folders within directories.
The structure of a hierarchical file system can also be documented from left to right to indicate a "file path." This is basically an address that shows where data is located within the various folders and directories of a computer. The root is often indicated on the left, since the path begins there, and each folder is separated by either a forward or back slash, depending on the OS being used. A file path might look like this: "root\folder\sub-folder\file_name." This is the exact same structure as a tree diagram, but simply represented from left to right rather than top to bottom.