A file is a collection of related information defined by its creator. A computer can store files on the disk (secondary storage), which provide long-term storage. Some examples of storage media are magnetic tape, magnetic disk, and an optical disk. Each of these media has its own properties like speed, capacity, data transfer rate and access methods. A file system normally organized into directories to ease their use. These directories may contain files and other directions.
The five major activities of an operating system in regard to file management are :
The creation and deletion of files.
The creation and deletion of directories.
The support of primitives for manipulating files and directories.
The mapping of files onto secondary storage.
The back up of files on stable storage media.
