外文翻译--网络目标.doc

附录1英文及其译文 Computer Networks Network Goals Some reasons are causing centralized computer systems to give way to networks. The first one is that many organizations already have a substantial number of computers in operation, often located far apart .Initially, each of these computers may have worked in isolation from the other ones, but at a certain time, and management may have decided to connect them to be able to correlate information about the entire organization. Generally speaking, the goal is to make all programs, data, and other resources available to anyone on the network without regard to the physical location of the resource and the user. The second one is to provider high reliability by having alternative sources of supply. With a network, the temporary loss of a single computer is much less serious, because its users can often be accommodated elsewhere until the service is restored. Another important reason for distributing computing power has to do with the relative price of computing versus communication. Now the cost of a small computer is negligible, so it becomes attractive to analyze the data at where it is captured, and only to send occasional summaries back to the computer center, to reduce the communication cost, which now represents a larger percentage of the total cost than it used to. Yet another reason of setting up a computer network is that a computer network can provider a powerful communication medium among widely separated people. Application of Networks One of the main areas of potential network use is access to remote data bases. It may someday be easy for people sitting at their terminals at home to make reservations for airplanes, trains, bused, boats, restaurants, theaters, hotels, and so on, at anywhere in the world with instant confirmation. Home banking, automated newspaper and fully automated library also fall in this category. Computer aided education is another possible field for using network, with m