Unix File System

Data in a Unix system is stored in files, which are same to ordinary office files.

Every file has contents, a name, a place to keep it and some administrative information such as its ownership and size. A file may contain a letter, or addresses and a list of names, or the source statements of a program or data to be used through a program.

Files are kept in storage devices that are commonly disks. A number of files can be stored on the disk. For organize these files, Unix operating system separates the disk into several logical units, where every unit can hold a group of associated files. These logical units are known as file systems.

Unix uses the hierarchical structure to store its files. This structure is referred to as the 'inverted' tree structure from its resemblance to an upside down tree. The file system begins with one primary directory known as root. Because the tree is upside down, the root is at on the top. The root directory symbolized via '/' (forward slash) has several directories under it.

The name of a file is provided through a path name which defines how to locate the file in the file system hierarchy. The path name is a series of component names separated through slash characters; a component is a sequence of characters which designates a file name which is uniquely contained in the past (directory) component. A full path name begins with a slash character and specifies a file which can be found through beginning at the file system root and traversing the file tree, follow the branches which lead to successive elements names of the path name.

There is no internal structure imposed on the contents of the files. Much structure given through the user could be used.