What are the four stages of the development process of computer networks?

The development of computer networks can be divided into several stages What are the characteristics of each stageAnswer: The development of computer networks can be divided into the following four stages.

1) terminal-oriented computer communication network: it is characterized by the computer is the center and controller of the network, the terminal is distributed everywhere around the central computer, presents a hierarchical star structure, each terminal shares the hardware and software resources of the host through the communication line, the main task of the computer is to carry out batch processing, after the emergence of the time-sharing system in the 60s of the 20th century, it has the ability of interactive processing and batch processing.

2) Packet switched network: Packet switched network is composed of communication subnet and resource subnet, with communication subnet as the center, not only sharing the resources of communication subnet, but also sharing the hardware and software resources of resource subnet. The sharing of the network adopts the queuing mode, that is, the packet switch of the node is responsible for the storage and routing of the group, and the transmission bandwidth is continuously (or dynamically) allocated to the two users who communicate, so that the utilization rate of the communication line can be greatly improved, which is very suitable for burst computer data.

3) Forming a computer network architecture: In order to make computer networks of different architectures interconnected, the International Organization for Standardization (ISO) has proposed a standard framework that can enable various computers to be interconnected into a network around the world - the basic reference model of open system interconnection OSIIn this way, as long as the OSI standard is followed, one system can communicate with any other system located anywhere in the world that also follows the same standard.

Private line (the network was the first military network in the United States), circuit switching network, packet switching network.

This should be a problem for the University of Electrical Engineering.

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4 stages. The first stage: remote online system, its mode is "terminal-communication line-computer"; Phase 2:

computer network communications; Phase 3: Standard, open computer network; Stage 4: High-speed, intelligent computer networks.

Computer, commonly known as computer, is a modern electronic computer machine used for high-speed calculation, which can perform numerical calculations, logical calculations, and also has the function of storage and memory. It is a modern intelligent electronic device that can operate according to the program and process massive amounts of data automatically and at high speed. A computer that consists of a hardware system and a software system without any software installed is called bare metal.

It can be divided into five categories: supercomputers, industrial control computers, network computers, personal computers, and embedded computers, and the more advanced computers include biological computers, photonic computers, quantum computers, etc. Inventor of the computer John von Neumann. The computer is one of the most advanced scientific and technological inventions of the 20th century, which has had an extremely important impact on human production and social activities, and has developed rapidly with strong vitality.

Its application field has expanded from the initial military scientific research application to all fields of society, and has formed a huge computer industry, which has led to technological progress on a global scale, which has triggered profound social changes, and computers have spread all over ordinary schools, enterprises, and institutions, and have entered the homes of ordinary people, becoming an indispensable tool in the information society.

1. Computer-terminal.

The geographically dispersed multiple terminal communication lines are connected to a central computer, and users can type programs in the terminals in their own offices, transmit them to the central computer through the communication lines, access and use resources for information processing in a time-sharing manner, and then send the processing results back to the user terminal through the communication lines for display or printing. This single-centric online system is called a remote online system for endpoints.

A simple computer is added before the main machine, which is specially used to process the communication information of the terminal and control the communication line, and can preprocess the user's work, this computer is called"Communication control processors"(CCP: Communication Control Processor), also known as pre-processor; A concentrator is set up in the place where the terminal equipment is concentrated, and the terminal is first gathered on the concentrator through the low-speed line, and then the concentrator is connected to the host computer by the high-speed line.

2. A computer network centered on a communication subnet.

Computers distributed in different locations are interconnected through communication lines to become a computer network. Network users can use the software, hardware and data resources of the local computer through the computer, and can also use other computer software, hardware and data resources in the network to achieve the purpose of resource sharing.

3. Network architecture standardization stage.

ISO developed the OSI RM as the basis for the research and development of a new generation of computer network standards. A variety of remote computer networks, local computer networks, and computer networks in urban areas that comply with OSI RM and protocol standards have begun to be widely used.

4. Network interconnection stage.

Various networks are interconnected to form a larger-scale interconnected network. The Internet is typical, characterized by interconnection, high speed, intelligence, and a wider range of applications.