Basic introduction
Inventor of the computer John von Neumann. The computer is one of the most advanced scientific and technological inventions of the 20th
15
A variety of computer pictures show
Century, the human production activities and social activities have had an extremely important impact, and with a strong vitality of rapid development. Its field of application from the initial military scientific research applications to all areas of society, has formed a huge scale of the computer industry, led to the global scope of technological progress, which led to a profound social change, the computer has been spread throughout the general schools, enterprises and institutions, into the homes of ordinary people, becoming an essential tool in the information society. It is one of the important symbols of mankind entering the information age. With the proposed development of the Internet of things, computers and other technologies once again set off a revolution in information technology, according to the definition of the China Internet of things school-enterprise alliance, the Internet of things is the combination of almost all the current technology and computer, Internet technology, to achieve the real-time environment between the object and the object and the state of the information **** enjoyment as well as the collection of intelligent, transmission, processing.
The application of computers is becoming more and more common in China, after the reform and opening up, the number of computer users in China continues to climb, the level of application continues to improve,
Computers
especially in the field of the Internet, communications, multimedia and other areas of the application of the good results. 1996 to 2009, the number of computer users from the original 6.3 million grew to 67.1 million, and the number of networked computer units rose from 29,000 to 59.4 million. The number of Internet users has reached 316 million, and there are 670 million mobile users of wireless Internet, of which the number of cell phone Internet users has reached 117 million, which is the first in the world.
2 Main Classifications
Super Type
Supercomputers
Supercomputers are usually computers that consist of hundreds, thousands or even more processors (machines) and are capable of calculating large-scale and complex subjects that cannot be accomplished by ordinary PCs and servers. Supercomputer is the strongest computer, the fastest computing speed, the largest storage capacity of a class of computers, is the level of scientific and technological development of the country and an important symbol of the comprehensive national power. Supercomputer has the strongest parallel computing ability, mainly used for scientific computing. In the meteorological, military, energy, space, prospecting and other fields to undertake large-scale, high-speed computing tasks. In the structure, although supercomputers and servers may be multiprocessor systems, the two are not substantially different, but modern supercomputers are more cluster systems, more focused on the performance of floating-point operations, can be watched as a high-performance servers focusing on scientific computing, and very expensive.
Networked
1, servers
Specializing in certain high-performance computers, can be through the network, to provide services to the outside world. Relative to ordinary computers, stability, security, performance and other requirements are higher, so the CPU, chipset, memory, disk system, network and other hardware and ordinary computers are different. Servers are the nodes of the network, storing and processing 80% of the data and information on the network, playing a pivotal role in the network. They are high-performance computers that provide a variety of services for client computers, and their high performance is mainly characterized by high speed computing power, long and reliable operation, and powerful external data throughput capability. The composition of the server is similar to an ordinary computer, also has a processor, hard disk, memory, system bus, etc., but because it is specially formulated for specific network applications, and thus the server and the microcomputer in the processing power, stability, reliability, security, scalability, manageability and other aspects of the difference is very large. Servers are mainly network servers (DNS, DHCP), print servers, terminal servers, disk servers, mail servers, file servers and so on.
2, workstation
is a personal computer and distributed network computing as the basis, mainly for professional applications, with a strong data computing and graphics, image processing capabilities to meet the engineering design, animation, scientific research, software development, financial management, information services, simulation and other professional fields and the design and development of high-performance computers. The most prominent feature of the workstation is that it has strong graphic exchange capability, so it has been rapidly applied in the field of graphic image, especially in the field of computer-aided design. Typical products are the Sun series workstations of the U.S. Sun Corporation.
Diskless workstation is no floppy disk, no hard disk, no CD-ROM drive connected to the LAN computer. In the network system, the workstation end of the operating system and application software are all placed on the server, the system administrator as long as the completion of the server management and maintenance, software upgrades and installations only need to configure a time after the entire network of all computers can use the new software. Therefore, diskless workstations have the advantages of cost savings, high system security, easy management and easy maintenance, which has a great attraction for network administrators.
The working principle of diskless workstations is that the boot chip (Boot ROM) of the network card sends out the boot request number to the server in different forms, and the server receives it and sends the boot data to the workstation according to different mechanisms. After the workstation downloads the boot data, the control of the system is transferred from the Boot ROM to some specific areas in the memory and the operating system is guided.
Based on the different boot mechanisms, the more commonly used diskless workstations can be divided into RPL and PXE. RPL stands for Remote Initial Program Load, and this technology is commonly used in Windows 95. PXE is the upgraded product of RPL, which stands for Preboot Execution Environment. PXE is an upgrade of RPL, which stands for Preboot Execution Environment. The difference between the two is that RPL is static routing, while PXE is dynamic routing, and its communication protocol adopts TCP/IP, realizing efficient and reliable connection with the Internet, which is commonly used in Windows98, Windows NT, Windows2000, and Windows XP.
3, hub
Hub (HUB) is a kind of *** enjoy the medium of the network equipment, its role can be simply understood as a number of machines connected to form a LAN, HUB itself can not recognize the destination address. All ports on the hub contend for the broadband of a ****-enjoyed channel, so as the number of network nodes increases and the amount of data transmission increases, the available bandwidth per node will decrease. In addition, the hub transmits data in the form of a broadcast, i.e., to all ports. For example, when host A in the same LAN transmits data to host B, the data packet is transmitted in a broadcast mode on the network structured as a HUB, sending the same information to all nodes on the network at the same time, and then each terminal determines whether or not to receive it by verifying the address information in the header of the data packet. In fact, only one terminal node receives the data, and all nodes are sent, in this way, it is easy to cause network congestion, and most of the data traffic is invalid, which results in the entire network data transmission efficiency is quite low. On the other hand, since the sent packets can be listened to by every node, it is easy to bring some insecurity to the network.
4, switch
Switch (Switch) is in accordance with the need to transmit information between the two ends of communication, with manual or automatic equipment to transmit information to meet the requirements of the corresponding route of the technology collectively. Broadly speaking, the switch is a communication system to complete the information exchange function of the equipment, it is the hub of the upgraded products, the appearance and the hub is very similar to its role and the hub is largely the same. But there is a difference between the two in performance: hubs use the **** enjoy bandwidth work, while the switch uses the exclusive bandwidth mode. That is, all ports on the switch have an exclusive channel bandwidth to ensure fast and effective transmission of data on each port, the switch provides users with an exclusive, point-to-point connection, packets are only sent to the destination port, and will not be sent to all ports, other nodes are difficult to listen to the information sent, so that when there are a lot of machines or a large amount of data, it is not easy to cause network congestion, and also to ensure that the data transmission security, while greatly improving the transmission efficiency, the difference between the two is more obvious.
5, router
Router (Router) is a network device responsible for path-finding, it is in the interconnection of the Internet from a number of paths to find the least amount of communication in a network path to provide users with communication. Routers are used to connect multiple logically separated networks to provide users with the best communication paths, routers use routing tables to select paths for data transmission, routing tables contain lists of network addresses and distances between addresses, routers use routing tables to find the correct path for a packet to travel from its current location to the destination address, and routers use a least time algorithm or an optimal path algorithm to adjust the paths for the delivery of information. Routers are created after switches, just as switches are created after hubs, so routers are also somewhat related to switches and are not completely independent of the two devices. Routers mainly overcome the lack of switches that cannot forward packets to routes.
Switch, router is a special network computer, its hardware base CPU, memory and interfaces, the software base is the network interconnection operating system IOS.
Switch, router and the same as the PC, there is a central processing unit CPU, and different switches, routers, its CPU is generally not the same, the CPU is the processing of switches, router center.
Memory is where switches and routers store information and data. CISCO switches and routers have the following types of memory components:
ROM (Read Only Memory) stores the switch's and router's power-on self-test, bootstrap program, and part or all of the bootstrap program. ROM (Read Only Memory) stores the switch, router power-on self-test (POST: Power-On Self-Test), bootstrap program, and some or all of the IOS.The ROM in the switch and router is erasable, so the IOS can be upgraded.
RAM (Random Access Memory) is similar to the random memory on a PC and provides storage for temporary information, as well as holding the current routing table and configuration information.
NVRAM (Nonvolatile Random Access Memory) stores the startup configuration files of switches and routers.NVRAM is erasable, allowing the configuration information of switches and routers to be copied into NVRAM.
FLASH flash memory, which is erasable and programmable, is used to store other versions of CISCO IOS for upgrading the IOS of the switch and router.
Interfaces are used to connect switches and routers to the network and can be categorized into LAN interfaces and WAN interfaces. Due to the different models of switches and routers, the number and type of interfaces are not the same. Common interfaces include the following:
Synchronous high-speed serial interface, which can be connected to DDN, Frame Relay, X.25, and PSTN (analog telephone line).
Synchronous/asynchronous serial port, the port can be set to work synchronously by software.
AUI port, the thick cable port. Generally requires an external converter (AUI-RJ45) to connect to a 10/100Base-T Ethernet network.
ISDN port, which can be connected to ISDN network (2B+D), can be used for LAN access to the Internet.
AUX port, which is an asynchronous port, mainly used for remote configuration, can also be used for unplugging backup, and can be connected with MODEM. It supports Hardware Flow Control.
Console port, which is an asynchronous port, mainly connects to a terminal or a computer running a terminal emulation program to configure switches and routers locally. Hardware flow control is not supported.
Industrial control type
It is a general term for a computer system that uses a bus structure to detect and control the production process and its electromechanical equipment and process equipment. Abbreviated industrial control machine. It consists of a computer and process input and output (I/O) through two major components. Computer is composed of the host, input and output devices and external disk drives, tape drives and so on. In the computer outside and increase part of the process input / output channels, used to complete the industrial production process detection data sent to the computer for processing; on the other hand, the computer to exercise control of the production process commands, information converted into industrial control object control variable signals, and then sent to the controller of the industrial control object to go. By the controller to exercise control over the operation of production equipment. The main categories of industrial controllers are: IPC (PC bus industrial computer), PLC (programmable control system), DCS (decentralized control system), FCS (fieldbus system) and CNC (numerical control system) five.
1, IPC
that is, based on the PC bus industrial computer. According to 2000 IDC statistics PC has accounted for more than 95% of general-purpose computers, because of its low price, high quality, high production, software/hardware resources, has been familiar with the majority of technicians and recognized, which is the basis of the industrial electric annoyance heat. Its main components for the industrial chassis, passive base plate and can be inserted into the composition of its various boards and cards, such as CPU card, I / O card. And take all-steel chassis, machine card pressure strip filter, double positive pressure fan design and EMC (Electro Magnetic Compatibility) technology to solve the industrial site of electromagnetic interference, vibration, dust, high / low temperature and other issues.
IPC has the following characteristics:
Reliability: Industrial PC has in dust, smoke, high / low temperature, humidity, vibration, corrosion and rapid diagnosis and maintainability, its MTTR (Mean Time to Repair) is generally more than 100,000 hours.
Real-time, industrial PC real-time on-line detection and control of industrial production processes, changes in working conditions to give a rapid response, timely collection and output adjustment (watchdog function which is not common PC), distress reset to ensure the normal operation of the system.
Expansion, industrial PC due to the use of baseboard + CPU card structure, and thus has a strong input and output functions, up to 20 boards can be expanded, with a variety of peripherals, boards, such as the industrial site with the road controller, video surveillance systems, vehicle detector connected to complete a variety of tasks.
Compatibility, can simultaneously utilize ISA and PCI and PICMG resources, and support a variety of operating systems, multi-language assembly, multi-tasking operating system.
2, programmable logic controller (PLC)
PLC English full name ProgrammableLogicController, the Chinese full name Programmable Logic Controller, the definition is: a digital algorithmic operation of the electronic system, designed to be applied in industrial environments. It uses a class of programmable memory for its internal storage program, the implementation of logical operations, sequence control, timing, counting and arithmetic operations and other user-oriented instructions, and through digital or analog input/output control of various types of machinery or production processes. A programmable control system (ProgrammableLogicController) is a digital algorithmic electronic system designed specifically for use in industrial environments. It uses a programmable memory to store instructions to perform logical operations, sequential control, timing, counting and arithmetic operations, etc., to control various types of machinery or production processes through digital or analog inputs and outputs.
Programmable controllers are a new type of general-purpose automatic control device for industrial environments developed by combining computer technology and automation control technology, and they appear as replacements for traditional relays. With the rapid development of microelectronics and computer technology, programmable controllers have more computer functions, not only to realize the logic control, but also has a data processing, communications, networks and other functions. Because it can change the control process through software, and has a small size, easy to assemble and maintain, simple programming, high reliability, strong anti-interference ability, etc., has been widely used in various fields of industrial control, and greatly promote the process of mechatronics.
3, decentralized control system (DCS)
It is a high-performance, high-quality, low-cost, flexible configuration of the decentralized control system series products can constitute a variety of independent control systems, decentralized control systems, DCS, monitoring and data acquisition system (SCADA), to meet the needs of a variety of industrial areas of process control and information management. The modular design of the system, reasonable hardware and software function configuration and easy to expand the ability to be widely used in a variety of large, medium and small power stations, decentralized control, power plant automation system renovation as well as iron and steel, petrochemical, paper, cement and other industrial production process control.
4, fieldbus system (FCS)
is an all-digital serial, two-way communication system. Measuring and control devices within the system such as probes, exciters and controllers can be interconnected, monitored and controlled. In the hierarchy of plant networks, it serves as both a localized network for process control (e.g., PLC, LC, etc.) and application of smart meters (e.g., frequency converters, valves, barcode readers, etc.), and has embedded functionality for distributing control applications over the network. Because of its broad application prospects, many foreign manufacturers with the strength to compete to invest in strength, product development. Internationally known fieldbus types are more than forty kinds, more typical fieldbus are: FF, Profibus, LONworks, CAN, HART, CC-LINK, etc..
5, CNC system (CNC)
Modern CNC system is the use of microprocessors or special microcomputer CNC system, stored in memory by the system program (software) to realize the control logic, part or all of the numerical control functions, and through the interface with peripheral equipment, called computer numerical control, referred to as CNC system.
Numerical control machine tool is a numerical control system as the representative of the new technology of the traditional machinery manufacturing industry penetration of the formation of mechatronics products; its technical scope covers many areas: (1) machinery manufacturing technology; (2) information processing, processing, transmission technology; (3) automatic control technology; (4) servo drive technology; (5) sensor technology; (6) software technology and so on.
Embedded type
That is, embedded systems (Embedded Systems), is a kind of application-centered, microprocessor-based, hardware and software can be tailored to adapt to the application of the system on the functionality, reliability, cost, volume, power consumption, and other comprehensive and stringent requirements of the special computer system. It generally consists of embedded microprocessors, peripheral hardware devices, embedded operating systems and user applications and other four parts. It is the fastest growing field in the computer market, and also a wide variety of computer systems with many different forms. Embedded systems include almost all electrical devices in life, such as palm pda, calculators, TV set-top boxes, cell phones, digital TVs, multimedia players, automobiles, microwave ovens, digital cameras, home automation systems, elevators, air conditioners, security systems, vending machines, cellular telephones, consumer electronic devices, industrial automation instruments and medical instruments.
The core component of the embedded system is the embedded processor, which is divided into four categories, i.e., Embedded Micro Controller Unit (Micro Contrller Unit, MCU, commonly known as MCU), Embedded Microprocessor Unit (Micro Processor Unit, MPU), Embedded DSP Processor (Digital Signal Processor, DSP) and Embedded DSP Processor (DSP). Processor (DSP) and embedded System on Chip (SOC). Embedded microprocessors generally have four characteristics:
1, real-time and multi-tasking has a strong support capacity, can complete multi-tasking and have a shorter interrupt response time, so that the internal code and the real-time operating system execution time is reduced to a minimum;
2, has a very strong function of the storage area to protect the function, this is due to the software structure of the embedded system has been modularized, and in order to avoid the software between modules, and to avoid the software between modules, and to avoid the software between modules, and to avoid the software between modules, and to avoid the software between modules, and to avoid the software between modules. And in order to avoid the cross effect of errors between software modules, the need to design a strong storage area protection function, but also conducive to software diagnostics;
3, scalable processor structure, in order to be able to quickly expand to meet the application of high-performance embedded microprocessor;
4, embedded microprocessor power consumption must be very low, especially for portable wireless and Mobile computing and communications equipment in the battery-powered embedded systems is more so, power consumption can only be mw or even μw level.
Molecular
Molecular computers are small in size, consume little power, are fast, and have large storage capacity. Molecular computers operate by absorbing the information present in the form of charges on molecular crystals and organizing them in a more efficient way. The arithmetic process of a molecular computer is the interaction of the protein molecule with the surrounding physicochemical medium. The conversion switch is the enzyme, and the program is extremely visible in the enzyme synthesis system itself and in the structure of the protein. A computer composed of biomolecules has the ability to operate in a biochemical environment, even in a biological organism, and to exchange with the external environment in the form of other molecules. It will therefore play an irreplaceable role in medical diagnosis and treatment, genetic tracking and bionic engineering. Molecular chip size is greatly reduced, but the efficiency is greatly improved, molecular computer to complete an operation, the time required is only 10 microseconds, 1 million times faster than the speed of human thought. Molecular computers have amazing storage capacity, 1 cubic meter of DNA solution can store 1 trillion trillion of binary data. Molecular computers consume very little energy, only one billionth of an electronic computer. Because the raw material of the molecular chip is a protein molecule, the molecular computer has both the function of self-repair, but also can be directly linked to the molecular living body.
Quantum type
Quantum computer is a new concept of computer that utilizes the quantum properties possessed by atoms for information processing. Quantum theory suggests that non-interacting atoms are in two states, called quantum superstates, at any given moment. Atoms rotate, i.e., they spin in both up and down directions at the same time, which coincides exactly with the 0 and 1 of an electronic computer. If a group of atoms are brought together, they do not perform linear operations as in an electronic computer, but perform all possible operations at the same time, e.g., a quantum computer processes data not step by step, but at the same time. Just 40 atoms computing together would be equivalent to the performance of a supercomputer today. Quantum computer to be in a quantum state of atoms as the central processor and memory, its computing speed may be 1 billion times faster than the Pentium 4 chip, like an information rocket, in a split second to search the entire Internet, you can easily crack any security code, hacking tasks a breeze, no wonder the U.S. Central Intelligence Agency is particularly interested in it.
Photonic type
Early 1990, the United States Bell Labs made the world's first photonic computer.
Photonic computer is a kind of optical signals from the digital
Photonic computer
operations, logical operations, information storage and processing of new computers. The basic component of the photonic computer is an integrated optical circuit, to have a laser, lens and nuclear mirror. Because photons are faster than electrons, photonic computers can run as fast as one trillion times. It has tens of thousands of times the storage capacity of modern computers and can also recognize and synthesize language, graphics and gestures.
Many countries have invested heavily in photonic computer research. With the combination of modern optics with computer technology and microelectronics, photonic computers will become a universal tool for human beings in the near future.
Nano type
Nanometer computer is a new type of high-performance computer developed with nanotechnology. Nanotube components are in the range of a few to several tens of nanometers in size, have a strong texture, are extremely conductive, and can be used to make computers instead of silicon chips. "A nanometer is a unit of measurement equal to 10 (-9) times a meter, which is about 10 times the diameter of a hydrogen atom. Nanotechnology is a new cutting-edge field of scientific research that developed rapidly from the early 1980s, with the ultimate goal that humans can directly manipulate individual atoms according to their own will to create products with specific functions. Nanotechnology is starting with microelectromechanical systems, where sensors, motors and various processors are placed on a silicon chip to form a system. Computer memory chips developed by applying nanotechnology are only hundreds of atoms in size, equivalent to one-thousandth of the diameter of a human hair. Not only do nanocomputers require almost no energy, but their performance is many times more powerful than today's computers.
Biological
Since the 1980s, bioengineers have devoted a lot of energy to the study of the human brain, neurons and receptors, with a view to developing a sixth-generation computer that can mimic the human brain's thinking, with low consumption and high efficiency -- a biological computer. Computer chips made from proteins can store up to one billion times more than ordinary computers. The density of biological computer components is 1 million times higher than that of neurons in the brain, and the speed of transferring information is 1 million times faster than that of human brain thinking.
Neurotype
It is characterized by the ability to achieve distributed associative memory. And it can simulate the learning function of human and animals to a certain extent. It is a kind of knowledge, learning, reasoning computer, with the ability to understand natural language, sound, text and images, and has the ability to speak, so that man and machine can use natural language to talk directly, it can use the existing and constantly learn the knowledge, thinking, association, reasoning, and draw conclusions, and can solve complex problems, with the ability to pool, memorize, and retrieve relevant knowledge.