Another integral part of the DSM is the server concept. The server is a process whose main task is to offer one or more services to one or more clients. To do this the server has to spend most of its time in a wait loop waiting for clients to connect to it. This division of labour is known as the client-server concept. It is used extensively in many systems today (see Mullender (1990) for a good overview of the state of client-server technology today).