An architecture in which the user's PC (the client) is the requesting machine and the server is the supplying machine, both of which are connected via a local area network (LAN) or a wide area network (WAN) such as the Internet. Throughout the late 1980s and early 1990s, client/server was the hot buzzword as applications migrated from minicomputers and mainframes with input/output terminals to networks of desktop computers.With ubiquitous access to company LANs and the Internet, almost everyone works in a client/server environment today. However, to be true client/server, both client and server must share in the business processing. To understand this principle, follow the examples below of a query to a million-record database. Each record is 1,000 bytes for a total of 1GB.The Web Is Client/ServerBecause of the Internet, terms such as "Web based" and "Web enabled" replaced the 1990s client/server buzzword, and client/server implies older legacy systems. However, although the client/server term may no longer be used much, Web-based systems today are entirely two-tier and three-tier client/server architectures. At the client side, the user's PC executes scripts in Web pages, and Internet-based Web servers and application servers process data before returning results to the user. See scripting language, Java applet, Web server, application server and database server.
A network architecture that distributes intelligence and responsibilities at several levels, with some machines designated as servers to serve the needs of client machines. A server can be a mainframe, minicomputer, or personal computer that operates in a time-sharing mode to provide for the needs of many clients. Client machines are complete, standalone computers that optimize the user interface, relying on servers to handle the more mundane tasks associated with application and file storage, network administration, security, and other critical functions. See also peer-to-peer.