Server Operating System

a server is an application, or device that performs services for connected clients as part of a client-server architecture. A server application, as defined by RFC 2616 (HTTP/1.1), is "an application program that accepts connections in order to service requests by sending back responses." Server computers are devices designed to run such an application or applications, often for extended periods of time with minimal human direction. Examples of d-class servers include web servers, e-mail servers, and file servers.