Hierarchical systems are as popular in computer systems as they are in other walks of life. The most obvious example of a hierarchical system in computers is a file system, in which directories have files and subdirectories beneath them. Such a file organization is, in fact, called a hierarchical file system .
In addition to file systems, many data structures for storing information are hierarchical in form. Menu-driven programs are also hierarchical, because they contain a root menu at the top of the pyramid and submenus below it.
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