Normally, when the computer is shutting down, every mounted storage device will undergo an unmounting process to ensure that all queued data was written to it, and to preserve the integrity of the file system structure on the media.
Before any of them can be used for storage, the means by which information is read and written must be organized and knowledge of this must be available to the operating system.
[2][3] Unix-like operating systems often include software and tools that assist in the mounting process and provide it new functionality.
Common examples include USB mass storage (flash drives), memory cards, CD-ROMs, and DVDs.
Some Unix-like systems have also introduced a concept called supermounting, as implemented in the Linux supermount-ng project.
The system automatically notices that the disk has changed and updates the mount point contents to reflect the new medium.