The use to which a device is put has aninfluence on the software and policies in the operating system and supportingutilities.

Examples:

• disk used for files requires the supportof file management software.

• disk used as a backing store for pagesin a virtual memory scheme depends on the use of virtual memory hardware andsoftware. 

Theseapplications have an impact on disk scheduling algorithms.

Another example, a terminal may be usedby an ordinary user or a system administrator.

 implying different privilege levels andperhaps different priorities in the operating system.