Kneeling for it! Article on computers
Computer development and the current situation
Computer network is a product of the close integration of computer technology and communications technology, which involves two areas of communications and computers. It was born to make the computer architecture has changed dramatically, in today's society and economy plays a very important role, it has made great contributions to the progress of human society. In a sense, the level of development of computer networks not only reflects a country's level of computer science and communications technology, and has become an important measure of its national strength and modernization.
Since the 1950s, the use of computers by people and various organizations to manage their information has grown rapidly. In the early days, limited to the technical conditions that made the computers of the time were very large and very expensive, it is impossible for any organization to provide individual employees with access to the entire computer, the mainframe must be *** enjoy, it is used to store and organize data, centralized control and management of the entire system. All users have terminal equipment connected to the system to enter databases into the mainframe for processing, or to take the results of processing in the mainframe and take them out through centrally controlled output devices. Its most typical feature is: through the host system to form most of the communication process, constitute the system of all communication protocols are proprietary to the system, the mainframe occupies an absolute dominant role in the system, all control and management functions are completed by the host.
With the continuous development of computer technology, especially the introduction of a large number of functionally advanced personal computers, so that each person can have full control of his own computer, to carry out the processing of his desired operations, the development of computing power presented in the form of personal computers (PCs) to become independent platforms, leading to the birth of a new computing structure --- distributed computing model.
Generally speaking, the development of computer networks can be divided into four stages:
Phase I: computer technology and communications technology combined to form the prototype of computer networks;
Phase II: on the basis of computer communications networks, to complete the study of network architecture and protocols, the formation of a computer network;
Phase III: in the resolution of the Computer networking and network interconnection standardization issues in the context of the proposed open system interconnection reference model and protocols, to promote the development of computer network technology in line with international standards;
Phase IV: computer networks to interconnection, high-speed, intelligent direction, and to obtain a wide range of applications.
The emergence of any new technology must have two conditions: that is, a strong social demand and the maturity of the prior technology. The formation and development of computer network technology also confirms this law. 1946 the world's first electronic digital computer ENIAC in the United States when the birth of computer technology and communications technology is not directly linked. the early 50's, due to the needs of the U.S. military, the U.S. semiautomatic ground-based air defense system SAGE to carry out the attempts to combine computer technology and communications technology. To realize such a purpose, the first step was to complete basic research on data communication technology. On the basis of this research, one can completely geographically dispersed multiple terminal communication lines connected to a central computer. Users can key in programs at their own terminals in the office and transmit them to the central computer through the communication line, and people call this single-centered on-line system a terminal-oriented remote on-line system. It is a kind of computer communication network. in the early 60's American Airlines built by a computer and distributed in the United States more than 2000 terminals composed of airline reservation system SABRE-1 is this kind of computer communication network.
With the development of computer applications, the emergence of multiple computer interconnection needs. This demand is mainly from the military, scientific research, regional and national economic information analysis and decision-making, large-scale business management. They want to interconnect computers distributed in different locations through communication lines into a computer-computer network. Network users can use the local computer software, hardware and data resources through the computer, but also can use other places connected to the network of computer software, hardware and data resources, in order to achieve the purpose of computer resources **** enjoy. Typical representative of this stage of research is the U.S. Department of Defense Advanced Research Projects Agency (ARPA, Advanced Research Projects Agency) ARPAnet (often called ARPAnet). 1969 ARPAnet only 4 nodes, developed to 40 nodes in 1973, 1983 has reached more than 100 nodes. ARPA network through wired, wireless and satellite communication lines, so that the network covers a wide area from the United States mainland to Europe and Hawaii.ARPR network is an important milestone in the development of computer network technology, it is the main contribution to the development of computer network technology is manifested in the following aspects:
1. Completed the definition of the computer network, classification and sub-topic of the description of the research content
2, proposed the concept of two-level network structure of resource sub-network and communication sub-network;
3, researched the data exchange method of message packet switching;
4, adopted a hierarchical structure of network architecture model and protocol system.
Future computers and computer technology
The key technologies of computers continue to evolve
Future computer technology will evolve in the direction of ultra-high speed, ultra-small size, parallel processing, and intelligence. The performance of CPUs, the core component of computers using silicon chips, will continue to grow, despite the constraints of physical limits. Inter, an example of a successful business driven by Moore's Law, expects to launch a microprocessor with 100 million transistors in 2001 and expects to launch a microprocessor integrating one billion transistors in 2010 with a performance of 100,000 MIPS (100 billion instructions per second). And supercomputers with 100 trillion times per second will appear to appear at the beginning of this century. Ultra-high-speed computers will use parallel processing technology, so that the computer system at the same time to perform multiple instructions or at the same time to multiple data processing, which is to improve the computer structure, improve the computer operating speed of the key technology.
At the same time the computer will have more intelligent components, it will have a variety of perceptual capabilities, a certain thinking and judgment ability and a certain natural language capabilities. In addition to providing natural input means (such as voice input, handwriting input), so that people can produce a sense of immersive interaction devices have appeared, virtual reality technology is the focus of this field of development.
The traditional magnetic storage, CD-ROM storage capacity continues to climb, the new mass storage technology tends to mature, the new memory per cubic centimeter storage capacity of up to 10TB (to a book of 300,000 words, it can store about 15 million books). Permanent storage of information will also become a reality, the millennium memory is being developed, such memory can be anti-interference, high temperature, shockproof, waterproof, corrosion-resistant. As such, a large number of today's literature can be preserved in its original flavor, and will be remembered for generations to come.
New computer systems continue to emerge
The high-speed development of silicon chip technology also means that the silicon technology is getting closer to its physical limits, for this reason, researchers around the world are stepping up research and development of new computers, computers from the architecture of the changes in the device and the technological revolution to produce a quantitative and even qualitative leap. New quantum computers, photonic computers, bio-computers, nano-computers, etc. will be in the 21st century into our lives, all over the field.
Quantum computers
Quantum computers are developed on the basis of the quantum effect, which utilizes the properties of a chain-like molecular polymer to represent the state of on and off, and the use of laser pulses to change the state of the molecules to move the information along the polymer, thus performing the calculations.
Data in a quantum computer is stored in quantum bits. Due to the quantum superposition effect, a quantum bit can be 0 or 1, and can also store both 0 and 1. Therefore, a quantum bit can store 2 data, and with the same number of storage bits, the storage capacity of a quantum computer is much larger than that of a usual computer. At the same time, quantum computers are able to implement quantum parallel computing, and their computing speed may be 1 billion times faster than the current personal computer Pentium III chip. There are three types of quantum computers currently under development: nuclear magnetic **** vibration (NMR) quantum computers, silicon-based semiconductor quantum computers, and ion trap quantum computers. Quantum computers are expected to be universal by 2030.
Photonic computers
Photonic computers, or all-optical digital computers, use photons instead of electrons, optical interconnects instead of wire interconnects, optical hardware instead of electronic hardware in computers, and optical arithmetic instead of electrical arithmetic.
Compared to electronic computers, optical computers are "wire-free computers" with a high density of parallel channels for information transfer. A 5-cent diameter coin-sized prism, its ability to pass more than the world's existing telephone cables many times. Light parallel, high-speed, naturally determines the parallel processing of optical computers is very strong, with ultra-high-speed computing speed. Ultra-high-speed electronic computers can only work at low temperatures, while optical computers can work at room temperature. Optical computers also have a similar fault tolerance with the human brain. When a component of the system is damaged or error, it does not affect the final calculation results.
At present, the world's first optical computer has been developed by more than 70 scientists from the United Kingdom, France, Belgium, Germany and Italy in the European **** body, and its computing speed is 1,000 times faster than that of an electronic computer. Scientists expect that the further development of optical computers will become one of the high-tech issues of the 21st century.
Bio-computer (molecular computer)
The computing process of a bio-computer is the interaction of protein molecules with the surrounding physical and chemical media. The computer's transfer switch is acted upon by enzymes, and the program is extremely visible in the enzyme synthesis system itself and in the structure of the proteins.
In the 1970s, it was discovered that deoxyribonucleic acid (DNA) can represent the presence or absence of information when it is in different states. the genetic code in a DNA molecule is equivalent to the stored data, which is transformed from one type of genetic code to another by biochemical reactions between DNA molecules. The genetic code before the reaction is equivalent to input data, and the genetic code after the reaction is equivalent to output data. If you can control this reaction process, then you can make a successful DNA computer.
Protein molecules are much smaller than the electronic components on a silicon chip, very close to each other, the biological computer to complete an operation, the time required is only 10 microseconds, faster than the speed of human thought 1 million times. DNA molecular computer has an amazing storage capacity, 1 cubic meter of the DNA solution, which can be stored in 1 trillion trillion binary data. DNA computer consumes a very small amount of energy, only one billionth of an electronic computer. Only one billionth of an electronic computer. As the raw material of the biochip is protein molecules, so the biological computer has the function of self-repair, but also can be directly linked to the living organism. It is expected that in 10 to 20 years, the DNA computer will enter the practical stage.
Nanocomputer
"Nano" is a unit of measurement, a nanometer is equal to 10 [-9] meters, about 10 times the diameter of the hydrogen atom. Nanotechnology is a new cutting-edge field of scientific research that developed rapidly from the early 1980s, with the ultimate goal of humans directly manipulating individual atoms of their own volition to create products with specific functions.
Now nanotechnology is starting with MEMS (microelectromechanical systems), where sensors, motors, and various processors are placed on a silicon chip to form a system. The application of nanotechnology developed computer memory chips, its volume is only a few hundred atoms in size, equivalent to the human hair diameter of one thousandth. Nanocomputers not only do not need to spend any energy, and its performance is many times more powerful than today's computers.
There has been some encouraging news about the successful development of nanocomputers, and researchers at Hewlett-Packard Labs have begun to apply nanotechnology to the development of chips, which, once successful, will pave the way for the development and production of other microcomputer components. The Internet Continues to Spread and Rise
When people talk about computers today, they inevitably associate them with networks; on the one hand, isolated, un-networked computers are becoming increasingly difficult to see, and on the other hand, the concept of computers is being expanded by networks. The rise of the Internet in the 1990s in the past in full swing, the impact of its wide-ranging and rapid popularization is unprecedented. There has never been a technology that has changed the way we learn, live and habituate as dramatically as the Internet. Almost all countries in the world have computer networks directly or indirectly connected to the Internet, making it a global computer network. People can communicate freely with other users around the world through the Internet, and can get all kinds of information from the Internet.
Looking back at the development of China's Internet, you can feel the rapid popularization of the Internet. In the past three years, China Internet Network Information Center (CNNIC) of China's Internet status survey shows that China's Internet development has shown explosive growth in January 2000, the number of computers on the Internet in China for 3.5 million, the number of statistics in 2001 for the 8.92 million, more than doubled; January 2000, the number of Internet users in China, 8.9 million; January 2001 statistics for the 22.5 million, nearly three times as much as the number of users on the Internet in China. In January 2000, the number of Internet users in China was 8.9 million; in January 2001, the number of users was 22.5 million, nearly three times as many; in January 2000, the number of domain names registered under the CN was 48,575; in January 2001, the number of domain names registered under the CN was 122,099, nearly three times as many; and the total capacity of the international circuits has reached 2,799M, eight times as many as the 351M in January 2000.
People have fully appreciated the charms of the network, and the Internet has greatly narrowed the boundaries of time and space. Time and space boundaries, through the network people can **** enjoy computer hardware resources, software resources and information resources.
Data Ready is a video ready to go.
In the next 10 years, the establishment of a transparent all-optical network is imperative, and the transmission rate of the Internet will increase by 100 times. Medical diagnostics, distance learning, e-commerce, video conferencing, and video libraries will be popularized on the Internet. At the same time, the construction of wireless networks will become the main battlefield for many companies to compete. In the future, we can connect to the Internet anytime and anywhere through wireless access to communicate, obtain information, and watch TV programs.
Mobile computing technologies and systems
With the rapid development and wide application of the Internet, the maturity of wireless mobile communication technologies, and the continuous improvement of computer processing power, new services and applications continue to emerge. Mobile computing has become an important direction for the development of the industry, as it is proposed to improve work efficiency and to be able to exchange and process information at any time.
Mobile computing consists of three elements: communication, computing, and mobility. These three aspects are both independent and interrelated. They have been studied for a long time before the concept of mobile computing was introduced, and mobile computing is the first time that they have been studied together. They can be transformed into each other, for example, the capacity of a communication system can be improved by computational processing (source compression, channel coding, caching, prefetching).
Mobility can bring new applications to computing and communications, but it also brings many problems. The biggest problem is how to face the challenges posed by the wireless mobile environment. In the wireless mobile environment, the signal is subject to a variety of interference and fading, there will be multipath and movement, to bring the signal time and frequency domain dispersion, band resource constraints, larger transmission delay and so on. Such an environment leads to many problems that have not been encountered in mobile communication networks and computer networks. First, the channel reliability problem and the system configuration problem. The limited wireless bandwidth and harsh communication environment make it necessary for various applications to be built on an unreliable and potentially disconnected physical connection. In a mobile computing network environment, the movement of mobile terminal locations requires a system that can be configured and updated in real time. Second, in order to truly enable all kinds of computing on the move, support for broadband data services is necessary. Third, how to extend the existing mobile governance technology mainly for voice services to broadband data services. Fourth, how to port some of the mature technologies in fixed computing networks to mobile computing networks.
All kinds of new microcomputer and information terminal products for global networked applications will become the main products. Portable computers, digital gene computers, cell phones and terminal products, as well as a variety of handheld personal information terminal products, mobile computing and digital communications will be integrated, cell phones will be embedded in high-performance chips and software, based on the standard unlimited communication protocols (such as bluetooth) to access the Internet, watch TV, listen to the radio. The new generation growing up on the Internet will naturally not take the car only as a transportation tool, the car will provide users with Internet access, office, home entertainment and other functions, to become the information platform on wheels.
Crossing the threshold of the new century, when we think about the future, we may wish to review this century's familiarity with computers. 1943 IBM President Thomas Wason said, "I think the demand for computers in the world market is about five units. In 1957 the editor of PrenticeHall USA wrote "I have traveled all over this country and talked to many of the best people, and I can be sure that the data-processing craze will not outstrip this year". 1968 IBM's Senior Computer Systems Engineer's microchip noted "But ... . what is it really good for?" In 1977 Ken Olson, founder and president of Digital Equipment Corporation, said "There is no reason for anyone to have a computer in their home." May what we say also prove to be shallow and conservative.