Network Servers

Today, most organization's networks are based on personal computers. Individual users have their own desktop computers, which are connected to one or more centralized computers, called network servers. A network server is usually a powerful personal computer with special software and equipment that enable it to function as the primary computer in the network. PC-based networks and servers offer companies a great deal of flexibility. For example, large organizations may have dozens or hundreds of individual servers working together at the heart of their network (see Fig. 1). When set up in such groups—sometimes called clusters or server farms—network servers may not even resemble standard PCs. For example, they may be mounted in large racks or reduced to small units called “blades" which can he slid in and out of a case. In these large networks, different groups of servers may have different purposes, such as supporting a certain set of users, handling printing tasks, enabling Internet communications, and so on. A PC-based server gives users flexibility to do different kinds of tasks (see Fig. 2). This is because PCs are general-purpose machines, designed to be used in many ways. For example, some users may rely on the server for e-mail access, some may use it to perform accounting tasks, and others may use it to perform word-processing or Data Base Management jobs. The server can support these processes, and many others, while storing information and programs for many people to use. Depending on how the network is set up, users may be able to access the server in multiple ways. Of course, most users have a standard desktop PC on their desk that is permanently connected to the network. Mobile users, however, may be able to connect a notebook PC or a handheld device to the network by wireless means. When they are away from the office, users may be able to use the Internet as a means of connecting to the company's network servers.