Computer Science An Overview _J. Glenn Brookshear _11th Edition

Over the years numerous variations of the basic index concept have been used.

One variation constructs an index in a hierarchical manner so that the index takes on

a layered or tree structure. A prominent example is the hierarchical directory

system used by most operating systems for organizing file storage. In such a case, the

directories, or folders, play the role of indexes, each containing links to its subin-

dexes. From this perspective, the entire file system is merely one large indexed file.