Computer networks have four stages: 1. The birth stage is a system connected for the purpose of transmitting information to achieve remote information processing or further resource sharing. 2. The formation stage is a collection of computers with independent functions that are interconnected for the purpose of sharing resources with each other. 3. The interconnection stage is an open and standardized network with a unified network architecture and compliance with international standards. 4. High-speed network technology stage; due to the mature development of local area network technology, the emergence of optical fiber and high-speed network technology, the entire network is like a large computer system that is transparent to users.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
Computer network refers to the connection of multiple computers and their external devices with independent functions in different geographical locations through communication lines. Under the management and coordination of network operating systems, network management software and network communication protocols , a computer system that realizes resource sharing and information transfer.
Computer networks are mainly interconnected by some general-purpose, programmable hardware that is not designed to achieve a specific purpose (for example, transmitting data or video signals). These programmable hardware can be used to transfer many different types of data and support a wide and growing number of applications.
The development stages of computer networks
Tracing the development history of computer networks, its evolution can be broadly divided into four stages:
1. Birth stage
The first-generation computer network before the mid-1960s was a remote online system centered on a single computer. Typical applications were composed of one computer and An aircraft booking system composed of more than 2,000 terminals across the United States. The terminal is a peripheral device of a computer, including a monitor and keyboard, without CPU and memory. As the number of remote terminals increases, a front-end machine (FEP) is added in front of the host computer. At that time, people defined computer networks as "systems connected for the purpose of transmitting information to achieve remote information processing or further resource sharing." Such communication systems already had the prototype of a network.
2. Formation stage
The second-generation computer network from the mid-1960s to the 1970s was based on multiple hosts interconnected through communication lines to provide users with Service, which emerged in the late 1960s, is typically represented by ARPANET, which was developed with the assistance of the U.S. Defense Advanced Research Projects Agency. The hosts are not directly connected by lines, but are interconnected after being transferred by the Interface Message Processor (IMP). The IMP and the interconnected communication lines between them are responsible for the communication tasks between hosts and constitute a communication subnet. The hosts interconnected by the communication subnet are responsible for running programs, providing resource sharing, and forming a resource subnet. During this period, the concept of network was "a collection of computers with independent functions interconnected for the purpose of sharing resources with each other", which formed the basic concept of computer networks.
3. Interconnection stage
The third generation computer network from the late 1970s to the 1990s was an open system with a unified network architecture and compliance with international standards. and standardized networks. After the rise of ARPANET, computer networks developed rapidly, and major computer companies successively launched their own network architectures and software and hardware products that implement these structures. Since there is no unified standard, it is difficult to interconnect products from different manufacturers. People urgently need an open, standardized and practical network environment. As a result, the two most important international architectures have emerged, namely the TCP/IP system. structure and the International Organization for Standardization's OSI architecture.
4. High-speed network technology stage
The fourth-generation computer network from the 1990s to the present, due to the mature development of local area network technology, the emergence of optical fiber and high-speed network technology, the entire The network is like a large computer system that is transparent to users and has developed into the Internet represented by the Internet.
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