Information is an important resource, which is the sum of all knowledge, knowledge and news extracted from the objective phenomenon of our society. Information is everywhere. The range of information exchange and transmission is very wide, and information is non-exclusive, lossless and transmissible in the process of exchange and transmission. As far as people know, anyone can query, retrieve and use all kinds of books and materials stored in the information base on the network or library. The content will not vary from person to person, and everyone can share the same information. Information is exclusive only when it becomes a right. Information is rich in permeability, so we should strive to break through the unnatural bondage of secrecy and expand our influence through various channels and means of communication. A good and valuable piece of information can not only be reused, but also spread. In addition, information becomes a resource when it is used. Information can be transmitted at the speed of light with high efficiency and high quality through various communication means. The essential characteristics of information are its non-exclusiveness, lossless and portability.
Information, matter and energy are called the three pillars of modern society. Information is the source of knowledge for human beings to know and transform the world. Without information, without information exchange, living things can't evolve and naturally can't be harmonious. If we can't use information effectively, there will be no human civilization, social development and scientific progress, and we can't control nature. The speed of the development of human society, to a certain extent, depends on the level of people's use of information. In the early days, the communication system consisted of telephone, telegraph and broadcast. With the continuous updating of communication technology, the current communication systems include TV, radar, fax, telemetry, remote control, remote sensing, computer and holography.
Generally speaking, in a communication system, a source generates a message (including information), a transmitter converts the message into a signal that can be transmitted on a channel, and a receiver demodulates and decodes the received signal in order to recover the message for the receiver. One of the main purposes of communication is to make the receiver get the same repeated information as the sender. What needs to be studied and paid attention to in communication is coding and noise.
An information system mainly includes four elements: personnel, machines, networks and databases. The database is the information source. There are many forms of information carriers, which can be books, papers, films, tapes, disks, optical disks, screens and so on. Therefore, databases as information sources can be digital libraries, archives, museums, machine-readable text files, electronic systems, etc. They provide information for the information superhighway and the Internet. Network mainly refers to the information network system composed of various information systems, as well as the necessary network standards, communication protocols, operating procedures and transmission codes. The network plays the role of information transmission channel. The information superhighway is a huge information transmission channel. At present, there are a lot of English data running on the information superhighway, and the circulation of Chinese data on the information superhighway should be gradually increased in the future. The machines in an information system are information facilities, which mainly include various physical devices for acquiring, transmitting, processing and utilizing information, such as computer terminals, fax machines, scanners, printers and so on. The personnel in the information system are the main body of information, which should include the developers, providers, managers and users of various information resources. People (personnel), machines (equipment), networks (networks) and data (databases) form an organic whole. Information production departments develop information products and establish various types of databases. Information superhighway, Internet and database are interrelated, and information users query information through computer terminals.