Shulou(Shulou.com)06/01 Report--

The concept of computer: now, when we talk about computers, except for special instructions, they all refer to electronic digital computers. The electronic digital computer is a kind of automatic electronic equipment, which processes the input original data according to the program written by people in advance in order to obtain the expected output information. and use this information to improve social productivity and improve people's quality of life. To help you better understand the concept of computer, let's first take a look at the definition of computer by von Neumann, known as the father of modern computers. Von Neumann is one of the most famous scientists in the computer field, who laid the architecture of modern computers. Von Neumann, who led the design of EDVAC (Electronic discrete variable automatic computer), described the concept of computer, which was called "the most influential paper in the history of computer science". Von Neumann called the computer an "automatic computing system" and pointed out that a "computer" is an electronic device that can accept input, process data, store data and produce output under the control of a program. Now, the electronic computer can not only be used as a calculation tool for numerical calculation, but also for information processing, and is often used in automatic control and other fields. With the development of computers and the expansion of application fields, computers are more and more used in information processing. Statistics show that more than 80% of today's computers will be mainly used for information processing. Because the computer in the early stage of its emergence is mainly for the sake of numerical calculation, so we continue the name "computer". Therefore, when we continue to use the term "computer", we should have a more comprehensive understanding of the meaning of computer. Nowadays, more and more people call it "computer", which mainly refers to the expansion and extension of the function of the human brain. The main reason why a computer is different from other computing devices is that it has the following three outstanding characteristics. 1. Basic devices are made up of electronic devices. Modern electronic computers are based on the working principle of digital circuits. Theoretically, the speed at which the computer processes data is only limited by the transmission speed of electricity, so the computer can achieve a very high running speed. two。 It has the ability to store information internally, and the internal information is expressed in binary. There are only "0" and "1" pulse signals in the digital circuit. In order to facilitate the hardware design, the internal information of the computer is expressed in binary. Because of its internal storage capacity, it is not necessary to obtain data from the outside every time, which minimizes the time it takes to process data and makes program control possible. This is an important difference between electronic computers and other types of computing devices. 3. The operation process is automatically controlled by the program because the computer has internal storage capacity, the computer can take instructions and data from the internal storage unit in turn to control the operation of the computer, this mode of work is called stored program control. It is one of the most important features of electronic computers. The application field of computer: now, the application of computer has been widely and deeply applied to all fields of human society. From scientific research, production, national defense, culture, education, health to family life, are inseparable from the services provided by computers. The computer has greatly improved the production efficiency and made the social productivity reach an unprecedented level. It is estimated that computers have more than 5000 uses and are increasing at a rate of 300 to 500 per year. For the convenience of discussion, we classify their application fields into the following categories. 1. Scientific computing, also known as numerical computing, refers to the use of computers to solve complex computational problems in scientific research and engineering technology. In the fields of natural science such as mathematics, physics, chemistry, astronomy and geography, as well as aerospace, automobile, shipbuilding, construction and other engineering and technical fields, the workload of calculation is very large, and these calculations are precisely the specialty of computers. At present, there are many numerical calculation packages used in various fields in the world, which greatly facilitates the majority of computing workers. The use of computer for numerical calculation can save a lot of time, manpower and material resources. two。 Information processing, also known as data processing, refers to the process in which people use computers to collect, store, sort, classify, count, process, utilize and spread all kinds of information, in order to obtain useful information as a basis for decision-making. At present, information processing is the most widely used field of computers. some data show that more than 80% of the computers in the world are mainly used for information processing. Modern society is an information society, with the high development of productive forces, resulting in a rapid expansion of information. At present, information, together with matter and energy, has been listed as the three pillars of human social activities. Therefore, in the various social activities carried out by human beings, we should not only consider the material conditions, but also seriously study the information. Computer information processing has been widely used in office automation (OA), computer-aided management and decision-making of enterprises, word processing, document management, information retrieval, laser phototypesetting, film and television animation design, computerized accounting, library management, medical diagnosis and other industries. Information has formed an independent industry, and multimedia technology has inserted wings for the take-off of the information industry. With multimedia, what is displayed in front of people is not only those boring numbers and words, but also the sound and image information that people like to hear and hear, voice and emotion. 3. Automatic control of industrial production process can effectively improve labor productivity. In the past, industrial control mainly used analog circuits, which had slow response speed and low precision, but now it has been gradually replaced by computer control. The computer control system sends the analog quantity, switch value and pulse quantity of the industrial field to the computer through the amplifying circuit and the A / D (A / D) and D / A (D / A) conversion circuit, which collects, displays and controls the data. Computer control system is not only used in industrial production, but also widely used in transportation, post and telecommunications, satellite communications and so on. Based on the characteristics of computer industrial control, this application of computer is often called real-time control or process control. 4. Computer-aided engineering computer can be used in computer-aided design, computer-aided manufacturing, assistant teaching, computer-aided testing and other aspects, collectively referred to as computer-aided engineering. Since the 1960s, many countries have begun the exploration of computer-aided design (CAD) and computer-aided manufacturing (CAM). With the application of computer graphics, the product structure, components and parts can be calculated, analyzed, compared and graphed. The convenience is that the parameters can be changed at any time, iterated and optimized until they are satisfied. On this basis, the designed products can be processed by further outputting the parts list, material list and paper tape or tape used in CNC machine tools, which is the concept of computer-aided manufacturing. Computer-assisted instruction (CAI) is an automatic system that uses computers to help students learn. It stores teaching contents, teaching methods and learning conditions in the computer, so that students can learn the knowledge they need easily. Computer aided testing (CAT) refers to the use of computers to carry out a large number of complex testing work. 5. Artificial intelligence (AI) refers to the use of computers to simulate human intelligent activities, such as perception, reasoning, learning, understanding and so on. Artificial intelligence is a new field of computer application, and the research in this field is still in its infancy. The research field of artificial intelligence mainly includes natural language understanding, intelligent robot, game, expert system, automatic theorem proving and so on. 6. The combination of computer network computer technology and communication technology can connect computers distributed in different locations together to form a computer network, in which people can share software, hardware and information resources. In particular, the emergence of Internet has broken the regional restrictions, shortened the time and distance for people to transmit information, and changed the human way of life. We will discuss this in more detail in later chapters. The main technical index and system configuration of computer system 1. The main performance index of the computer 1) word length: word length is the number of binary data bits that can be directly processed by CPU, which is directly related to the calculation accuracy, function and speed of the computer. The longer the word length, the stronger the processing power. The common word lengths of microcomputers are 8 bits, 16 bits and 32 bits. 2) Operation speed: operation speed refers to the number of instructions that the computer can execute per second, generally using MIPS as the unit. 3) dominant frequency: the dominant frequency refers to the clock frequency of the computer, expressed in units of MHz. 4) memory capacity: memory capacity refers to the total number of bytes in internal memory that can store information, generally in KB and MB units. 5) Peripheral configuration: peripheral refers to the input / output device of the computer. 6) Software configuration: including operating system, computer language, database language, database management system, network communication software, Chinese character support software and other application software. / 2. The main configuration of microcomputer system the basic configuration of microcomputer mainly includes host computer, keyboard, disk drive, hard disk, display and so on. The hardware system of microcomputer / 1. Microprocessor microprocessor consists of an arithmetic unit and a controller, which is the core of a microcomputer. Microprocessors are usually divided into 8-bit, 16-bit, 32-bit and 64-bit according to word length. / 2. Memory is divided into memory and external memory. Memory is the memory in which the CPU can be addressed directly by the address line. Memory is divided into two types of RAM,ROM. RAM is a readable and writable memory, which is used to store frequently changing programs and data. As soon as the power is off, the programs and data in RAM are lost. ROM is a read-only memory, and the programs and data in ROM will not be lost even if the power is off. / 3. Input device it is a device for the outside world to transmit information to the computer. In the microcomputer system, the most commonly used input device is the keyboard. A disk drive (i.e., a disk drive) is also an input device. / 4. The function of the output device is to transmit the data information from the computer to the external media. the most commonly used output devices are monitors and printers.

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