From an architectural point of view, the client or server can be a workstation, a central processor, a local processor or a departmental processor. Generally, a client is best described as a workstation. It is possible, however, for a large host system to be a client that requests data from a small computer such as a workstation.

Usually a server is a central processor, a local system or a departmental system. It is possible, however, for a workstation to be a server that provides data to a central processor. See Figure 1.

Figure 1. Client/Server Cooperative Processing