Although a number of the PC operating systems now available (such as Windows and the Apple OS) provide for peer-to-peer networking (discussed in the next chapter), in most cases one thinks of a network as being made up of clients and servers.
A client is a computer that allows a user or users to log on to the network and take advantage of the resources available on the network. A client computer will run a client operating system (such as Windows XP Professional). The purpose of the client is to get a user onto the network; therefore, client computers don't usually have the processing power, the storage space, or the memory found on a server because the client does not have to serve up resources to other computers on the network (although dropping PC prices and advances in technology allow you to buy client computers that have the power and storage equal to a server that was purchased a year or two earlier).
A server, on the other hand, is typically a much more powerful computer that runs a network operating system (NOS) such as Microsoft Windows Server 2003 or Novell NetWare. The server provides centralized administration of the network and serves up the resources that are available on the network, such as printers and files (the NOS provides the server with these capabilities). The administrator of the server decides who can and cannot log on to the network and which resources the various users can access.
Most LANs consist of many clients and a few servers. While one server always controls user logons, other servers can specialize in providing certain types of resources (such as print servers and file servers, which are discussed in the next chapter). Figure 1.2 provides a diagram of a "typical" PC network.
Figure 1.2. PC networks consist of clients and servers.
Obviously the scale of a network will depend on whether the network is used by a huge corporation or has been set up for a home business. For example, a home network and a business network will probably both make use of hubs as a way to physically connect the computers. But a home network won't necessarily have network servers and print servers that are required to provide services to the large number of users found on a corporate network.
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Because client and server computers both have processing capabilities, the workload on a PC network can be distributed between the client and the server. This differs from the centralized computing provided by mainframes and minicomputers, where the central computer provides all the processing power for the users logged on via dumb terminals. |
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