Client/server architecture is becoming increasingly more popular in library automation, but there is still considerable confusion about what it is. Even vendors who claim to have client/server products use widely differing definitions. We were recently asked to give our definition, and share it here:
Client/server divides functions into client (requestor) and server (provider) subsystems, with standard communication methods (such as TCP/IP and Z39.50) to facilitate the sharing of information between them. The dividing line between client and server can be anywhere along a broad continuum: at one end only the user interface has been moved onto the client; at the other end almost all applications have been moved onto the client and the database may be distributed. Client/ server architecture does not presuppose that client and server are on separate machines, although that is the more common approach. One client may be used to communicate with several different servers.
A GUI (graphical user interface) is often called client/server, but unless information moves from the server to the client in machine-readable (raw) form, and the client does the formatting to make it human-readable, it is not, in our opinion, true client/server. Further, there is nothing in the client/server architecture that requires a GUI.
Library Technology Reports has commissioned a report by ISCI of client/server technology in library automation. The study will define and discuss client/ server systems and will differentiate them from host-based systems. The principal products now in general release or in development will be described. The implications for writing RFPs for client/server will also be addressed. Publication has been scheduled for 1995.