In a sense, the internet can be said to be the product of the cold war between the United States and the Soviet Union. In the United States, the 1960s was a very special era. In the early 1960 s, the Cuban nuclear missile crisis occurred and the cold war between the United States and the Soviet Union warmed up. The threat of nuclear annihilation has become a topic in people's daily life. At the same time that the United States blocked Cuba, the Vietnam War broke out and political crises occurred in many third world countries. Due to the stimulation of American federal funds and the influence of public fear, the "cold war in the laboratory" also began. People think that maintaining the leading position in science and technology will determine the outcome of the war. The progress of science and technology depends on the development of computer field. By the end of 1960s, every major federally funded research center, including purely commercial organizations and universities, had the latest computer equipment provided by the emerging computer industry in the United States. The idea of sharing data among computer centers is developing rapidly. The U.S. Department of Defense believes that if there is only one centralized military command center, in case this center is destroyed by the nuclear weapons of the former Soviet Union, the military command of the whole country will be paralyzed and the consequences will be unimaginable. Therefore, it is necessary to design such a decentralized command system consisting of decentralized command points. When some command points are destroyed, others can still work normally, and these scattered points can get in touch through some form of communication network. From 65438 to 0969, ARPA- Advanced Research Projects Agency of U.S. Department of Defense began to build a network called ARPAnet, which connected several military and research computer mainframes in the United States. At first, ARPANET only connected four hosts. As far as military requirements are concerned, it is under the protection of high-level secrets of the US Department of Defense. Technically, it does not have the conditions for external promotion. 1983, ARPA and the us department of defense communications bureau successfully developed the TCP/IP protocol for heterogeneous networks. The University of California, Berkeley took this protocol as a part of its BSD UNIX, which made it popular in the society and gave birth to the real Internet. From 65438 to 0986, the National Science Foundation (NSF) established NSFnet WAN on the basis of five supercomputers for scientific research and education services by using the TCP/IP communication protocol developed by ARPAnet. With the encouragement and support of the National Science Foundation of the United States, many universities, government-funded research institutions and even private research institutions have incorporated their local area networks into NSFnet. At that time, the military part of ARPAnet had left the home network and established its own network-Milnet. ARPANET, the father of network, was gradually replaced by NSFnet. At 1990, ARPANET withdrew from the historical stage. Nowadays, NSFnet has become one of the important backbone networks of the Internet. From 65438 to 0989, CERN successfully developed the World Wide Web, which laid the foundation for wide-area hypermedia information interception/retrieval on the Internet. By the early 1990s, the Internet had actually become a "network within a network"-each subnet was responsible for its own erection and operation costs, and these subnets were interconnected through NSFnet. Since NSFnet was funded by the government, the biggest boss of the Internet at that time was the American government, but to some extent, some small private bosses were also added. The expansion of the Internet in the 1980s not only brought about quantitative changes, but also brought about some qualitative changes. Due to the entry of various academic groups, enterprise research institutions and even individual users, Internet users are no longer limited to computer professionals. New users find that joining the Internet can not only enjoy the supercomputer of NSFnet, but also communicate with each other, which is more attractive to them. As a result, they gradually regard the Internet as a tool for communication, rather than just enjoying the computing power of the NSFnet supercomputer. Before the 1990s, the use of the Internet was always confined to research and academic fields. Commercial organizations' access to the Internet is always troubled by laws or traditional problems of one kind or another. In fact, government agencies such as the National Science Foundation, which once funded the construction of the Internet, are not interested in commercial activities on the Internet. 199 1 year, three companies in the United States operated their own CERFnet, PSInet and Alternet networks, which can provide customers with internet networking services to some extent. They set up the Commercial Internet Association (CIEA), announcing that users can use their Internet subnets for any commercial purpose. The emergence of Internet business service providers has enabled industrial and commercial enterprises to finally enter the Internet in an upright manner. As soon as commercial organizations step into the unfamiliar Internet world, they will find its great potential in communication, information retrieval and customer service. As a result, its situation is out of control. Countless enterprises and individuals from all over the world have flooded into the Internet, which has brought a new leap in the history of Internet development.
1, the first computer 1946 Inventors of the first electronic computer ENIAC (Eniac Professor Moakley and Dr. eckert from the University of Pennsylvania, USA. Features: More than 8000 electronic tubes/kloc-0 are used, weighing 30 tons, covering an area of about 170 square meters, consuming 150 kilowatts, and the calculation speed is 5000 additions per second. Von Neumann proposed: architecture: controller, arithmetic unit, memory, input device, output device. Important ideas: stored programs and binary methods stored programs: programs and data exist in memory [all computers based on the principle of stored programs are called von Neumann computers] 2. Four stages of computer development (1) The first generation: electron tubes (2) the second generation: transistors (3) the third generation: integrated circuits (4) the fourth generation: large-scale integrated circuits. Neural network computer (3) Nominal use time of biological computer, basic component programming/software system use operation speed start time end time upper limit lower limit Electron tube computer era 1946 Electron tube machine language or assembly language scientific computing engineering computing tens of millions of transistors FORTRAN, COBOL, ALGOL in the mid-1950s and late 1960s, and already had an operating system. Scientific calculation, engineering calculation, data processing, hundreds of thousands of times, the era of integrated circuit computers, the mid-1960s and early 1970s, the integrated circuit operating system became more and more comprehensive. Since the early 1970s, hundreds of thousands of times and millions of times of large-scale integrated circuits (LSI) have been developed, and semiconductor chips with higher integration have been used as the main storage system software to realize computer automation and intelligence. The research of computer networks has developed rapidly in all aspects of society. Based on large scale integrated circuits, microcomputers have developed millions of times. 3. Development trend (in terms of structure and function) (1) Megascale (2) Miniaturization (3) Networking (4) Multimedia. 4. A new generation method: divide (1) the mainframe era (2) the minicomputer era (4) according to the function and calculation mode.
The invention of the computer has had a far-reaching impact on society, and people think its impact can be compared with the invention of the steam engine. With the development of computer, the network has followed. In human history, no technology and its application have ever developed so fast as the Internet, which has had such a huge impact on people's work, life, consumption and communication. With the advent of highly information-based network society, the traditional mode of production, lifestyle and living conditions of human beings will inevitably undergo earth-shaking changes. At present, human society is in a historic leap period, from a highly industrialized era to a preliminary computer network era. The network has brought great convenience to human work, study and life. The development of computer network technology has had an indelible and far-reaching impact on the development of human technology history. Some scholars even think that the development of computer technology will lead to a new scientific revolution. Therefore, we must have a profound understanding and a clear understanding of the profound changes brought by the network to all levels of social production and life. A correct understanding of the power of computer and network is the basis for us to discuss the influence of computer network on contemporary social economy, politics and culture, and the premise for discussing the relationship between computer network and social development. For modern society, the popularization and development of computer network will have a great impact on all aspects of social production and life, especially after the network is widely accepted and used as a tool for production and life, the role of computer network will become even greater. Let's briefly introduce the influence of computer network on society.
First of all, the network will promote the development of social productive forces at a faster speed. Human society has experienced several technological revolutions, and the arrival of the computer network era has announced the arrival of a new scientific and technological revolution. The main element of the computer and network era is information. Through computers and the Internet, the development of information technology will be accelerated unprecedentedly, the channels for people to understand and transmit information will increase, the speed will become faster, and the timeliness and effectiveness of information will be stronger. Meanwhile, the development of information technology will promote the progress and development of information-related industries, such as biotechnology and electronic technology. And some new materials and new energy development and utilization technologies will also be greatly developed in this process, which will make the status of science and technology as the first productive force in human society more prominent, and may even make science and technology gradually rise to an independent force to enter the material production process and become a decisive factor in determining the size of productive forces.
Secondly, for individuals, through the use of computers and networks, human production methods and production capacity have also been greatly developed. We can foresee that in the near future, through the connection of computer network, people can finish their work and study tasks without leaving home, save more time to deal with other things, and liberate people in action and even in thought. In addition, we can use the computer network to input our working thinking and methods into the machine, so as to complete the tasks we have to complete by ourselves. In enterprise production, not only the appearance, packaging and performance of products can be completely designed by computer, but also the whole process of product production, packaging and distribution can be controlled by computer, which saves a lot of manpower and financial resources. Moreover, we can also combine the computers in enterprises and companies into a network system, and a host computer controls the extension, thus forming an effective connection network to ensure the coordination of the whole production process. Entering the production process through the network can save a lot of production links with manpower as the main factor, and let them engage in more flexible production activities, which can also be said to be a leap in the history of human production development.
Third, the computer network will open the era of electronic management. Through the computer network, it will bring new ways and methods to the management of government departments. The future e-government management mode may be realized. From now on, government departments at all levels, from senior government functional departments to local governments, can perform their management functions electronically through the Internet, and can establish a special electronic system for government management, issue management notices, and issue new policies, laws and related government news. Governments and departments at all levels can establish electronic databases from their own management direction to provide effective help for the introduction and inquiry of policies. In addition, through these networks, the relevant departments can know the relevant information and the situation reflected by the grassroots in time, so as to make timely policy adjustments. Through this professional and prosperous computer network, the government's management work and dissatisfied functions can be more clear, and the transparency to the general public will also increase, thus making the government's actions more supervised by the masses and ensuring social stability. In addition, online voting can also be used to decide the introduction of relevant policies and major resolutions, so as to enhance the enthusiasm of citizens to participate in and discuss state affairs and ensure effective contact between the government and the masses.
Finally, the computer network will also have a great impact on the changes of people's lives. Through computers and networks, we can have a new public and private life field in the future, which will make people's lifestyle take on a brand-new form. The network makes the communication between people more convenient, makes the relationship between people closer and makes the distance between the world smaller and smaller. In addition, the network will provide us with any services we need, such as sending and receiving information, contacting relatives and friends, shopping online, understanding current affairs and news, watching TV programs, and completing work and study tasks. In short, an efficient network system will solve all the problems we need to solve.
Visible, the development of computer network will have a positive impact on human society, will cause revolutionary changes in social production and life, and will promote the development of human civilization to a higher stage.
Brief introduction of computer development history
With the development of production and the progress of society, the computing tools used by human beings are from simple to complex, from low to advanced, such as abacus, slide rule, hand-operated mechanical computer, electric mechanical computer and so on. 1946, the world's first electronic digital computer (ENIAC) was born in the United States. This computer * * * consists of 18000 electron tubes, with an area of 170m2, a total weight of 30t, a power consumption of 140kw, and an operation speed of 5000 additions and 300 multiplications per second.
In just over 50 years, electronic computers have gone through four stages of development: electron tubes, transistors, integrated circuits (ic) and very large scale integrated circuits (VLSI), which makes computers smaller and smaller, more powerful, cheaper and more widely used. At present, it is developing to intelligent (fifth generation) computers.
1. the first generation of electronic computers
The first generation of computer electricity is from 1946 to 1958. They are large in size, low in operation speed, small in storage capacity and expensive. It is also inconvenient to use. In order to solve a problem, the complexity of the program is difficult to express. This generation of computers is mainly used for scientific calculation and only used in important departments or scientific research departments.
2. The second generation of electronic computers
The second generation computer is from 1958 to 1965. They all use transistors as electronic devices, the operation speed is nearly 100 times faster than that of the first generation computers, and the volume is one tenth of the original. The software adopts computer algorithm language. This generation of computers is not only used for scientific calculation, but also for data processing, transaction processing and industrial control.
3. The third generation of electronic computers
Third-generation computers from 1965 to 1970. The main feature of this period is the emergence of small and medium-sized integrated circuits as electronic devices and operating systems, which makes the functions of computers stronger and stronger and the application scope wider and wider. They are not only used in scientific calculation, but also in word processing, enterprise management, automatic control and other fields. The information management system combining computer technology and communication technology came into being, which can be used in production management, traffic management, information retrieval and other fields.
4. The fourth generation of electronic computers
The fourth generation computer refers to the computer made of large scale integrated circuits (LSI) and very large scale integrated circuits (VLSI) as the main electronic devices after 1970. For example, the 80386 microprocessor can integrate about 320,000 transistors on a chip with an area of about10mm × 10/0mm. ..
Another important branch of the fourth generation computer is the microprocessor and microcomputer developed on the basis of large-scale and ultra-large-scale integrated circuits.
Microcomputer has roughly gone through four stages:
The first stage is 197 1 ~ 1973, with 4004, 4040 and 8008 microprocessors. 197 1 year, Intel developed a MCS4 microcomputer (CPU 4040, four-bit computer). Later, MCS-8 with 8008 as the core was introduced.
The second stage is 1973 ~ 1977, which is the development and perfection stage of microcomputer. Microprocessors are 8080, 8085, M6800 and Z80. The original product is MCS-80 (CPU Intel (CPU is 8080, 8-bit computer). In the later period, there were TRS-80 (CPU is Z80) and APPLE-II (CPU is 6502), which was once popular all over the world in the early 1980s.
The third stage is 1978 ~ 1983. The development stages of 16-bit microcomputer are 8086, 808880 186, 80286, M68000 and Z8000. The representative product of microcomputer is IBM-PC(CPU is 8086). The peak products at this stage are Apple's Macintosh( 1984) and IBM's PC/AT 286 (1986).
The fourth stage is the development stage of 32-bit microcomputer from 1983. Microprocessors have successively introduced 80386 and 80486. 386 and 486 microcomputers are the original products. 1993, Intel introduced a microprocessor named Pentium or P5 with 64-bit internal data channel. Now Pentium III (also called P7) microprocessor has become the mainstream product, and Pentium IV is expected to be launched in June 2000.
Therefore, the performance of microcomputer mainly depends on the performance of its core equipment, the microprocessor (CPU).
5. The fifth generation computer
The fifth generation computer will combine information collection, storage, processing, communication and artificial intelligence with formal reasoning, association, learning and interpretation. Its architecture will break through the traditional concept of Von Neumann machine and realize highly parallel processing.
Second, the characteristics of the computer
The basic characteristics of a computer are as follows:
1, with strong memory.
There is a large storage device in the computer, which can not only store a large number of information materials such as words, graphics, images and sounds for a long time, but also store programs that command the computer to work.
2. The calculation accuracy is high and the logical judgment is accurate.
It has high-precision control or high-speed operation tasks that human beings can't complete. It also has reliable judgment ability and realizes the automation of computer work, thus ensuring reliable judgment, rapid response and sensitive control of computer control.
3. High-speed processing ability
It has magical operation speed, which can reach one billion or even several billion times per second. For example, it took a mathematician more than ten years to calculate the approximate value of pi to 707 digits, but if modern computers are used to calculate it, it may be completed in an instant, reaching 2 million digits after the decimal point.
4, can automatically complete various operations
The computer is controlled and operated internally. As long as the pre-programmed application program is input into the computer, the computer can automatically complete the scheduled processing tasks according to the steps specified in the program.
1.3 computer application field and development direction
First, the field of computer applications.
At present, the application of computers can be summarized as the following aspects.
1. Scientific calculation (or numerical calculation)
Early computers were mainly used for scientific calculation. At present, scientific computing is still an important field of computer application. Such as high-energy physics, engineering design, earthquake prediction, weather prediction, aerospace technology, etc. Because computers have high computing speed, accuracy and logical judgment ability, new disciplines such as computational mechanics, computational physics, computational chemistry and biological cybernetics have emerged.
2. Process detection and control
Computer detection system is called computer detection system, which uses computer to automatically detect some signals in industrial production process, stores the detected data in the computer, and then processes the data as needed. Especially, the intelligent instrument formed by the introduction of computer technology has pushed industrial automation to a new height.
3. Information management (data processing)
Information management is the most widely used field of computer at present. Use computers to process, manage and operate any form of data, such as enterprise management, material management, report statistics, account calculation, information retrieval, etc. In recent years, many domestic institutions have established their own management information systems (MIS). Manufacturing resource planning software (MRP) has also been adopted by manufacturing enterprises, and electronic information exchange system (EDI) has been gradually applied to commercial circulation, that is, paperless trade.
4. Computer-aided system
1) computer aided design (CAD) refers to the use of computers to help designers carry out engineering design, thus improving the automation of design work and saving manpower and material resources. At present, this technology has been widely used in the design of circuits, machinery, civil buildings, clothing and so on.
2) Computer Aided Manufacturing (CAM) refers to the management, control and operation of production equipment through computers, so as to improve product quality and reduce production costs. Shorten the production cycle and greatly improve the working conditions of manufacturing personnel.
3) Computer-aided testing (CAT) refers to the use of computers for complex and large-scale testing.
4) Computer-aided instruction (CAI) refers to an automatic system that uses computers to assist teachers in teaching and help students learn, so that students can easily learn what they need.
Second, the development direction of computers
The future computer will be based on VLSI, and will develop in the direction of giant, miniaturization, networking and intelligence.
1. Huge
Giant refers to a computer with higher computing speed, larger storage capacity and stronger functions. The supercomputer being developed at present can operate at a speed of billions of times per second.
2. Miniaturization
Microcomputer has entered small instruments and equipment such as instruments and household appliances. At the same time, it is also the heart of industrial control process, which makes instruments and equipment "intelligent". With the further development of microelectronics technology, microcomputers such as notebook computers and palmtop computers will be welcomed by people with better cost performance.
3. Establish a working network
With the deepening of computer application, especially the increasing popularity of home computers, on the one hand, it is hoped that many users can enjoy information resources, on the other hand, it is also hoped that computers can transmit information to each other for communication.
Computer network is the product of the combination of modern communication technology and computer technology. Computer network plays an increasingly important role in the management of modern enterprises such as banking system, commercial system and transportation system.
Become smart
The research of computer artificial intelligence is based on modern science. Intelligentization is an important direction of computer development. The new generation of computers will be able to simulate the mechanism of people's sensory behavior and thinking process, and carry out "seeing", "listening", "speaking", "thinking" and "doing", and have the ability of logical reasoning, learning and proof.
The first generation was the era of electron tube computers (1946- 1958).
The era of the second generation transistor computer (1958- 1964)
The third generation of small and medium-sized integrated circuit computers (1964- 197 1)
The fourth generation LSI computer era (197 1 till now)
The birth of artificial intelligence system computer in 1990s marked the advent of the fifth generation computer.
The first computer (ENIAC) was born in the United States in February 1946. American mathematician von Neumann proposed program storage. With the support of the United States War Department, the development of ENIAC began in 1943 and was completed in 1946. John von neumann (1903- 1957), a Hungarian American, was born in Budapest, Hungary on February 28th, 1903. His father is a banker and his family is well-off, so he attaches great importance to his children's education. Von Neumann was brilliant since he was a child, with a wide range of interests and unforgettable reading memory. It is said that he was able to chat with his father in ancient Greek at the age of 6 and mastered seven languages in his life. He is best at German, but when he thinks about ideas in German, he can translate them into English at the speed of reading. Can quickly repeat the content word for word, and can do so after several years. 19 1 1 year-192 1 year, when von Neumann was studying in Lu Se Lun Middle School in Budapest, he made his mark and was highly valued by teachers. Under Fichte's individual guidance, he co-published his first mathematical paper, when von Neumann was less than 18 years old. 192 1- 1923 studied at the university of Zurich. Soon after, he got his Ph.D. in Mathematics from Budapest University with 1926, when von Neumann was only 22 years old. 1927- 1929 von Neumann has been a mathematics lecturer at the University of Berlin and the University of Hamburg. 1930 accepted the position of visiting professor at Princeton University and went to the United States. 193 1 became the first batch of tenured professors at Princeton university, when he was less than 30 years old. 1933 transferred to the Institute of Advanced Studies, became one of the first six professors, and worked there all his life. Von Neumann is an honorary doctor of Princeton University, University of Pennsylvania, Harvard University, Istanbul University, University of Maryland, Columbia University and Munich Institute of Advanced Technology. He is an academician of the National Academy of Sciences of the United States, the National Academy of Natural Sciences of Peru and the National Academy of Forestry of Italy. From 65438 to 0954, he served as a member of the American Atomic Energy Commission. 195 1 to 1953, President of the American Mathematical Society. 1954 In the summer, von Neumann was diagnosed with cancer. 1957 died in Washington on February 8, at the age of 54. 196965438+February, the predecessor of the internet, the ARPA network in the United States, was put into operation, which marked the rise of the computer network that we often say. This computer internet system is a packet-switched network. Packet switching technology fundamentally changed the concept, structure and network design of computer networks, and laid the foundation for later computer networks. In the early 1980s, with the popularization of PC personal computer applications, the demand for PC networking increased, and various computer local area networks based on PC interconnection were launched one after another. The typical structure of microcomputer LAN system in this period is the * * * shared file server structure on the * * shared media communication network platform, that is, all networked PCs are equipped with a dedicated network file server, which can be shared. PC is a "everything" little sparrow computer. The main task of each PC user is still to run on his own PC, and only when he needs to access disk files can he access the file server through the network, which embodies the cooperative work between computers in the computer network. Because of the use of high-speed transmission media such as coaxial cable and optical fiber, which are much higher than PSTN, the speed and efficiency of PC accessing resources on the Internet are greatly improved. This microcomputer network based on file server divides the computers in the network: PC is user-oriented and microcomputer server is dedicated to providing file resources. So it is actually a client/server model. The computer network system is a very complicated system, and the communication between computers involves many complicated technical problems. In order to realize computer network communication, computer network adopts layered method to solve network technical problems. However, due to the existence of different levels of network system architecture, it is difficult to realize the interconnection between its products. Therefore, the International Organization for Standardization (ISO) officially promulgated the OSI international standard "Basic Reference Model of Open Systems Interconnection" in 1984, which standardized the computer network architecture. In 1990s, computer technology, communication technology and computer network technology based on computer and network technology developed rapidly. Especially after the United States 1993 announced the establishment of national information infrastructure NII, many countries in the world have formulated and established their own NII, which greatly promoted the development of computer network technology and made computer networks enter a brand-new stage. At present, the global high-speed computer internet with the United States as the core has been formed, and the Internet has become the most important and greatest treasure house of human knowledge. The U.S. government began to develop faster and more reliable 2 (Internet 2 and Next Generation Internet at 1996 and 1997 respectively. It can be said that network interconnection and high-speed computer network are becoming the development direction of the latest generation of computer networks.