A server is a network computer that provides access to various network resources. Modern networks of any size are server-based or client-server networks. File servers are either minicomputers or high-specification PCs with large-capacity storage devices, high-speed processors and large amounts of RAM. The storage devices used are typically RAID (redundant array of inexpensive disks) devices, which employ multiple disks to store programs and data, affording a high degree of fault tolerance. Faulty disk drives can be replaced without shutting down the server - a facility known as hot swapping. A file server provides services such as user authentication, access to home directories and shared file space, and printing services. A specialised network operating system (NOS) provides the necessary network management functions. Examples of include Windows 2008 Server and Novell Netware. A network administrator administers the file server remotely from a workstation. The file server itself is normally housed in a rack in an air-conditioned and temperature-controlled room accessible only to authorised personnel.
A rack-mounted IBM server