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Unformatted text preview: s to real Web browsers. 12.1 Client-Server Programming Model
Every network application is based on the client-server model. With this model, an application consists of a server process and one or more client processes. A server manages some resource, and it provides some service for its clients by manipulating that resource. For example, a Web server manages a set of disk ﬁles that it retrieves for clients. An FTP server manages a set of disk ﬁles that it stores and retrieves for clients. An X server manages a bit-mapped display, which is paints for clients, and a keyboard and mouse, which it reads for clients. The X server is interesting because it is always close to the user while the client can be far away. Thus proximity plays no role in the deﬁnitions of clients and servers, even though we often think of servers as being remote and clients being local. The fundamental operation in the client-server model is the transaction depicted in Figure 12.1. A transaction consists of four steps: 1. When a client needs service, it initiates a transaction by sending a request to the server. Fo...
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- Spring '10
- The American