The term network operating system is used to refer to two rather different concepts: * A specialised operating system for a network device such as a router, switch or firewall. * An operating system oriented to computer networking, to allow shared file and printer access among multiple computers in a network, to enable the sharing of data, users, groups, security, applications, and other networking functions. Typically over a local area network (LAN), or private network. This sense is now largely historical, as common operating systems generally now have such features included.