File system

A file system (or filesystem) is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device(s) which contain it.

Description
A file system organizes data in an efficient manner and is tuned to the specific characteristics of the device. There is usually a tight coupling between the operating system and the file system. Some file systems provide mechanisms to control access to the data and metadata. Ensuring reliability is a major responsibility of a file system. Some file systems provide a means for multiple programs to update data in the same file at nearly the same time.

File systems used by Apple

 * Apple File System
 * Hierarchical File System
 * HFS Plus
 * Macintosh File System