The emergence of computer network interconnection: The Internet began with the ARPANET in the United States in 1969. Usually the Internet generally refers to the Internet, while the Internet refers specifically to the Internet. This method of connecting computer networks to each other can be called [Network Internet], on this basis, a global Internet network covering the world called the Internet was developed.
The emergence of computer network interconnection:
The Internet began with the ARPANET in the United States in 1969. Usually internet refers to the Internet in general, while Internet refers to the Internet specifically. This method of connecting computer networks to each other can be called "network interconnection". On this basis, a global Internet network covering the world called the Internet was developed, which is a network structure that is interconnected. The Internet is not the same as the World Wide Web. The World Wide Web is just a global system based on hypertext links and is one of the services that the Internet can provide.
Tracing back to the development history of computer networks, its evolution can be broadly divided into three stages:
(1) A remote online system centered on a single computer constitutes a terminal-oriented computer network.
(2) A computer network in which multiple host computers are interconnected through lines.
(3) A computer network with a unified network architecture and following international standardized protocols.
The so-called online system is a central host computer that connects a large number of geographically dispersed terminals. As early as the early 1950s, the semi-automatic ground air defense system established by the United States was to collect information from ground radars and other measurement and control equipment through communication lines to a central computer for processing, pioneering the combination of computer technology and communication technology. try. This kind of simple "terminal-communication line-computer" system became the prototype of computer network. Strictly speaking, there is a fundamental difference compared with the computer network that will develop maturely in the future. In addition to a central computer, the other terminal devices in such a system have no autonomous processing functions and cannot be considered a computer network. But now, in order to distinguish it more clearly from the computer network in which multiple computers are interconnected later, it is specifically called a terminal-oriented computer network.
As the number of connected terminals increases, in order to reduce the load on the central computer responsible for data processing, a front-end processor (FEP) or communication controller is installed between the communication line and the central computer. CCU (Communication Control Unit) is specifically responsible for communication control with terminals. There is a division of labor between data processing and communication control, so as to better utilize the data processing capabilities of the central computer. In addition, in areas where terminals are concentrated, concentrators and multiplexers are set up. It first connects terminals in nearby clusters to the concentrator or multiplexer through low-speed lines, and then connects to the remote center computer through high-speed communication lines, modems, and remote center computers. The front-end machines are connected to form a remote online system, which improves the utilization rate of communication lines and saves investment in remote communication lines.
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