distributed system

distributed system A system which contains a number of hardware elements such as computers and ROUTERS which are connected by some transmission technology. Such systems consist of a number of executing programs which interact with each other via transmission lines. Many of the computers in a distributed system act as CLIENTS to computers known as SERVERS. There are many reasons for implementing a system in a distributed fashion: the first is to ensure that processing power is as close to the users as possible; the second is to ensure a high degree of robustness, for example via the use of DATA REPLICATION; and the third is to enable hardware to be easily added as the resource demands of the applications running on the distributed system start increasing. There are many problems facing the designer of a distributed system including predicting the performance of a particular design, keeping all the clocks in the system synchronized, and ensuring that if a hardware element of the system malfunctions users are, at best, only affected in a minimal way. Distributed systems have been in existence since the 1970s; but they were mainly closed systems confined to a physical location such as a building. The rise of the Internet has meant that many distributed systems are open to the world. This has given rise to a major problem: ensuring that such systems are secure. The best-known distributed system is the comparatively simple WORLD WIDE WEB which consists of a very large number of clients running BROWSERS and a large number of WEB SERVERS.