A computer that shares its resources, such as printers and files, with other computers on the network but is used only to store and retrieve information.An example of this is a Network File System (NFS) server which shares its disk space with others

The term also refers to a software package which provides some service to other (client) programs. The connection between client and server is normally by means of message passing, often over a network, and uses some protocol to encode the client's requests and the server's responses. The server may run continuously (as a daemon), waiting for requests to arrive or it may be invoked by some higher level daemon which controls a number of specific servers.

Servers are often dedicated, meaning that they perform no other tasks besides their server tasks. On multiprocessing operating systems, however, a single computer can execute several programs at once. A server in this case could refer to the program that is managing resources rather than the entire computer.