Supercomputers usually refer to computers composed of hundreds, thousands or even more processors (computers) that can calculate large and complex tasks that ordinary PCs and servers cannot complete. A supercomputer is a type of computer with the most powerful functions, the fastest computing speed, and the largest storage capacity. It is an important symbol of the country's scientific and technological development level and comprehensive national strength. Supercomputers have the strongest parallel computing capabilities and are mainly used for scientific computing. It undertakes large-scale, high-speed computing tasks in meteorology, military, energy, aerospace, mining and other fields. Structurally, although both supercomputers and servers may be multi-processor systems, there is no substantial difference between the two. However, modern supercomputers mostly use cluster systems and pay more attention to the performance of floating point operations. High-performance servers for scientific computing, and very expensive. 1. Server
Specifically refers to certain high-performance computers that can provide services to the outside world through the network. Compared with ordinary computers, the requirements for stability, security, performance, etc. are higher, so the CPU, chipset, memory, disk system, network and other hardware are different from ordinary computers. The server is the node of the network, storing and processing 80% of the data and information on the network, and plays a decisive role in the network. They are high-performance computers that provide various services to client computers. Their high performance mainly reflects high-speed computing capabilities, long-term reliable operation, and powerful external data throughput capabilities. The composition of a server is similar to that of an ordinary computer, including a processor, hard disk, memory, system bus, etc. However, because it is specially formulated for specific network applications, servers and microcomputers have differences in processing power, stability, reliability, security, There are huge differences in scalability, manageability, etc. Servers mainly include network servers (DNS, DHCP), print servers, terminal servers, disk servers, mail servers, file servers, etc.
2. Workstation
It is a kind of workstation based on personal computers and distributed network computing. It is mainly oriented to professional application fields and has powerful data computing and graphics and image processing capabilities. High-performance computers designed and developed to meet the needs of engineering design, animation production, scientific research, software development, financial management, information services, simulation and other professional fields. The most prominent feature of the workstation is its strong graphics exchange capability, so it has been rapidly used in the field of graphics and images, especially in the field of computer-aided design. Typical products include the Sun series workstations of the American Sun Company.
A diskless workstation refers to a computer connected to a local area network without a floppy disk, a hard disk, or an optical drive. In a network system, the operating system and application software used on the workstation are all placed on the server. The system administrator only needs to complete the management and maintenance of the server, and the software upgrade and installation only need to be configured once. All computers will be able to use the new software. Therefore, the diskless workstation has the advantages of cost saving, high system security, easy management and easy maintenance, which is very attractive to network administrators.
The working principle of a diskless workstation is that the boot chip (Boot ROM) of the network card sends a startup request number to the server in different forms. After the server receives it, it sends startup data to the workstation according to different mechanisms. After the workstation downloads the startup data, system control is transferred from the Boot ROM to certain specific areas in the memory and the operating system is booted.
According to different startup mechanisms, the more commonly used diskless workstations can be divided into RPL and PXE. RPL is the abbreviation of Remote Initial Program Load. This technology is commonly used in Windows95. PXE is an upgrade of RPL, which is the abbreviation of Preboot Execution Environment. The difference between the two is that RPL is a static routing, while PXE is a dynamic routing. Its communication protocol uses TCP/IP to achieve an efficient and reliable connection to the Internet. It is commonly used in Windows98, Windows NT, Windows2000, and Windows XP.
3. Hub
A hub (HUB) is a network device that shares media. Its function can be simply understood as connecting some machines to form a local area network. The HUB itself cannot identify the destination address. All ports on the hub compete for the bandwidth of a shared channel, so as the number of network nodes increases and the amount of data transmission increases, the available bandwidth of each node will decrease. In addition, the hub transmits data in the form of broadcast, that is, transmitting data to all ports. For example, when host A in the same LAN transmits data to host B, the data packets are transmitted in a broadcast manner on the network with a HUB architecture. The same information is sent to all nodes on the network at the same time, and then passed by each terminal. Verify the address information in the packet header to determine whether to receive it. In fact, generally speaking, there is only one terminal node that receives data, and data is sent to all nodes. 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 being quite high. Low. On the other hand, since every node can listen to the data packets sent, it is easy to bring some insecurity risks to the network.
4. Switch
Switch (Switch) is based on the needs of both ends of the communication to transmit information, and uses manual or automatic equipment to send the information to be transmitted to the corresponding device that meets the requirements. A collective name for routing technologies. In a broad sense, a switch is a device that completes the information exchange function in a communication system. It is an upgraded product of a hub. It looks very similar to a hub and its function is roughly the same as a hub. However, there are differences in performance between the two: the hub uses a shared bandwidth mode, while the switch uses an exclusive bandwidth mode. That is, all ports on the switch have 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. Data packets are only sent to the destination port, not to the destination port. It will be sent to all ports, and it is difficult for other nodes to listen to the information sent. This will not easily cause network congestion when there are many machines or a large amount of data. It also ensures the security of data transmission and greatly improves the transmission efficiency. The difference between the two is more obvious.
5. Router
A router is a network device responsible for path finding. It searches for a network path with the least traffic among multiple paths in the Internet to provide Communicate to users. Routers are used to connect multiple logically separate networks to provide users with the best communication path. Routers use routing tables to select paths for data transmission. Routing tables contain a list of network addresses and distances between addresses. Routers use routing tables to lookup The correct path of the data packet from the current location to the destination address. The router uses the least time algorithm or the optimal path algorithm to adjust the path of information delivery. Routers come after switches, just like switches come after hubs, so routers and switches are also related to each other and are not two completely independent devices. Routers mainly overcome the shortcomings of switches that cannot forward data packets to routes.
Switches and routers are special network computers. Its hardware foundation is CPU, memory and interfaces, and its software foundation is the network interconnection operating system IOS.
Switches and routers, like PCs, have a central processing unit (CPU), and different switches and routers generally have different CPUs. The CPU is the processing center of switches and routers.
Memory is where switches and routers store information and data. CISCO switches and routers have the following memory components:
ROM (Read Only Memory) stores the memory that switches and routers automatically store when they are powered on. Check (POST: Power-On Self-Test), startup program (Bootstrap Program) and part or all of IOS. The ROM in switches and routers is rewritable, so the IOS can be upgraded.
RAM (Random Access Memory) is similar to the random access memory on a PC, providing storage of temporary information and saving the current routing table and configuration information.
NVRAM (Nonvolatile Random Access Memory) stores the startup configuration files of switches and routers.
NVRAM is rewritable, and the configuration information of switches and routers can be copied to NVRAM.
FLASH flash memory is rewritable and programmable. It is used to store other versions of CISCO IOS and is used to upgrade the IOS of switches and routers.
Interfaces are used to connect switches and routers to the network, and can be divided into two types: LAN interfaces and WAN interfaces. Due to different models of switches and routers, the number and type of interfaces are also different. Common interfaces mainly include the following:
High-speed synchronous serial port, which can be connected to DDN, Frame Relay, X.25, and PSTN (analog telephone lines).
Synchronous/asynchronous serial port, software can be used to set the port to synchronous working mode.
AUI port, which is the thick cable port. Generally, an external converter (AUI-RJ45) is required to connect to the 10/100Base-T Ethernet network.
ISDN port can connect to ISDN network (2B+D) and can be used as a LAN to access the Internet.
AUX port, this port is an asynchronous port, mainly used for remote configuration, can also be used for dial-up backup, and can be connected with MODEM. Support hardware flow control (Hardware Flow Control).
Console port, this port is an asynchronous port, mainly connected to the terminal or the computer running the terminal emulation program, and configures the switch and router locally. Hardware flow control is not supported. It is a general term for a computer system that uses a bus structure to detect and control the production process, its electromechanical equipment, and process equipment. Referred to as industrial computer. It consists of two major parts: computer and process input and output (I/O). A computer is composed of a host, input and output devices, external disk drives, tape drives, etc. A part of the process input/output channel is added outside the computer to complete the detection data of the industrial production process and send it to the computer for processing; on the other hand, the commands and information that the computer needs to control the production process are converted into control variables of the industrial control object. The signal is then sent to the controller of the industrial control object. The controller exercises control over the operation of the production equipment. The main categories of industrial computers are: IPC (PC bus industrial computer), PLC (programmable control system), DCS (distributed control system), FCS (field bus system) and CNC (numerical control system).
1. IPC
It is an industrial computer based on PC bus. According to IDC statistics in 2000, PCs have accounted for more than 95% of general-purpose computers. Because of their low price, high quality, large output, and rich software/hardware resources, they have been familiar and recognized by the majority of technical personnel. This is why industrial computers The basis of irritation. Its main components are an industrial chassis, a passive backplane and various boards that can be inserted into it, such as CPU cards, I/O cards, etc. It also adopts all-steel casing, machine-pressed filter screen, dual positive pressure fans and EMC (Electro Magnetic Compatibility) technology to solve problems such as electromagnetic interference, vibration, dust, high/low temperature and other problems in industrial sites.
IPC has the following characteristics:
Reliability: Industrial PC has the ability to withstand dust, smoke, high/low temperatures, moisture, vibration, corrosion and rapid diagnosis and maintainability, and its MTTR ( Mean Time to Repair) is generally more than 100,000 hours.
Real-time, industrial PC performs real-time online detection and control of the industrial production process, responds quickly to changes in working conditions, and performs timely acquisition and output adjustment (watchdog function is not available in ordinary PCs) ), self-reset in distress to ensure normal operation of the system.
Expandability, industrial PC adopts baseboard + CPU card structure, so it has strong input and output functions, can be expanded to up to 20 boards, and can be connected with various peripherals and boards in industrial sites, such as Connected to road controllers, video surveillance systems, vehicle detectors, etc. to complete various tasks.
Compatibility, it can use ISA, PCI and PICMG resources at the same time, and supports various operating systems, multi-language assembly, and multi-task operating systems.
2. Programmable Logic Controller (PLC)
PLC’s full name in English is ProgrammableLogicController, and its full name in Chinese is programmable logic controller. The definition is: an electronic system for digital operation. Designed for use in industrial environments. It uses a type of programmable memory to store programs internally, perform user-oriented instructions such as logical operations, sequence control, timing, counting and arithmetic operations, and control various types of machinery through digital or analog input/output. or production process. The programmable control system (ProgrammableLogicController) is a digital computing operation electronic system specially designed for application in industrial environments. It uses a programmable memory to store instructions for performing operations such as logical operations, sequence control, timing, counting and arithmetic operations, and controls various types of mechanical equipment or production through digital or analog input and output. process.
The programmable controller is a new general-purpose automatic control device suitable for industrial environments developed by combining computer technology and automation control technology. It appears as a replacement for traditional relays. With the rapid development of microelectronics technology and computer technology, programmable controllers have more computer functions. They can not only realize logic control, but also have data processing, communication, network and other functions. Because it can change the control process through software, and has the characteristics of small size, easy assembly and maintenance, simple programming, high reliability, and strong anti-interference ability, it has been widely used in various fields of industrial control, greatly promoting the development of mechatronics. process.
3. Distributed control system (DCS)
It is a high-performance, high-quality, low-cost, flexible configuration of distributed control system series products, which can constitute various independent Control systems, decentralized control systems DCS, and supervisory control and data acquisition systems (SCADA) can meet the needs for process control and information management in various industrial fields. The system's modular design, reasonable software and hardware function configuration and easy expansion capabilities can be widely used in decentralized control of various large, medium and small power stations, transformation of power plant automation systems, steel, petrochemicals, papermaking, cement, etc. Industrial production process control.
4. Fieldbus System (FCS)
It is a fully digital serial, two-way communication system. Measurement and control equipment such as probes, actuators and controllers within the system can be interconnected, monitored and controlled. In the hierarchy of factory networks, it not only serves as a local network for process control (such as PLC, LC, etc.) and application intelligent instruments (such as frequency converters, valves, barcode readers, etc.), but also has embedded control applications distributed on the network. Function. Due to its broad application prospects, many powerful foreign manufacturers are competing to invest in product development. There are more than forty known fieldbus types in the world. Typical fieldbuses include: FF, Profibus, LONworks, CAN, HART, CC-LINK, etc.
5. CNC system (CNC)
Modern CNC system is a CNC system that uses a microprocessor or a dedicated microcomputer, and is controlled by system programs (software) stored in the memory in advance. Logic realizes part or all of the CNC functions and connects with peripheral devices through interfaces, which is called computer numerical control, or CNC system for short.
CNC machine tools are mechatronic products formed by the penetration of new technologies represented by CNC systems into the traditional machinery manufacturing industry; their technical scope covers many fields: (1) Machinery manufacturing technology; (2) Information Handling, processing, and transmission technology; (3) automatic control technology; (4) servo drive technology; (5) sensor technology; (6) software technology, etc. 1. Desktop
Also called desktop, it is an independent computer that has no connection with other components. It is larger than notebooks and netbooks, including the host computer, monitor, etc. The equipment is generally relatively independent and generally needs to be placed on a computer desk or a special workbench. Hence the name desktop. It is a very popular microcomputer, and most of the machines used in people's homes and businesses are desktop computers. The performance of desktop computers is relatively stronger than that of laptop computers. Desktop computers have the following characteristics:
Heat dissipation. Desktop computers have advantages that notebook computers cannot match. Desktop computer cases have been widely used because of their large space and good ventilation.
Extensibility. The desktop chassis is convenient for users to upgrade hardware, such as optical drives and hard drives. For example, a desktop case has 4-5 optical drive slots and 4-5 hard drive slots. It is very convenient for users to upgrade their hardware in the future.
Protective. Desktop computers fully protect hardware from dust. And the water resistance is good; this development is not very good in notebooks.
Clarity. The power on, key, reset button, USB, and audio interfaces of the desktop computer case are all on the front panel of the case, making it convenient for users to use.
However, desktop computers are less portable and are very convenient compared to laptops.
2. All-in-one computer
An all-in-one computer is a computer composed of a monitor, a computer keyboard and a mouse. Its chip, motherboard and monitor are integrated together, and the monitor is a computer, so as long as the keyboard and mouse are connected to the monitor, the machine can be used. With the development of wireless technology, the keyboard, mouse and monitor of an all-in-one computer can be connected wirelessly, and the machine only has one power cord. This solves the problem of many and complicated desktop cables that has been criticized by people. Some all-in-one computers also have TV reception and AV functions, and also integrate special software, which can be used as special machines for specific industries.
3. Notebook or Laptop
Also known as laptop or laptop, it is a small, portable personal computer, usually weighing 1-3 kg . In addition to the keyboard, the laptop also provides a touchpad (TouchPad) or a touch point (Pointing Stick), which provides better positioning and input functions.
Laptop computers can be roughly divided into 6 categories: business type, fashion type, multimedia application, Internet type, learning type, and special purpose. Business laptops can generally be summarized as having strong mobility, long battery life, and many business software; fashionable appearance is mainly aimed at fashionable women; multimedia application laptops have strong graphics, image processing capabilities and multimedia capabilities, especially It is the playback capability and it is an enjoyment product. Moreover, multimedia laptops mostly have relatively powerful independent graphics cards and sound cards (both support high-definition), and have larger screens. Netbooks are lightweight and low-configuration laptops that have functions such as surfing the Internet, sending and receiving emails, and instant messaging (IM), and can smoothly play streaming media and music. Netbooks emphasize portability and are mostly used for mobile Internet access on business trips, tourism, and even public transportation. The learning body is designed in the shape of a notebook, adopts standard computer operation, and fully integrates multiple machine functions such as learning machine, electronic dictionary, repeater, point reader, and student computer. Special-purpose laptops are models that serve professionals and can be used in harsh environments such as scorching heat, severe cold, low pressure, high altitude, strong radiation, war, etc. Some are relatively bulky, such as those used at the "ASUS Everest Base Camp" in the early stages of the Olympic Games. ASUS laptops used in the IT Service Area.
4. Handheld computer (PDA)
A handheld computer is a small, lightweight, portable and practical device that runs on an embedded operating system and embedded application software. , inexpensive handheld computing devices. It is simpler and lighter than a laptop in terms of size, functionality and hardware configuration. In addition to managing personal information (such as address books, plans, etc.), handheld computers can also browse the Internet, send and receive emails, and can even be used as a mobile phone. They also have: recorder function, English-Chinese-Chinese dictionary function, global Clock comparison function, reminder function, leisure and entertainment function, fax management function, etc. The power supply of handheld computers usually uses ordinary alkaline batteries or rechargeable lithium batteries. The core technology of handheld computers is the embedded operating system, and the competition between various products mainly lies here.
A smartphone is created by adding mobile phone functions to a handheld computer. In addition to the call function of a mobile phone, a smart phone also has PDA sub-functions, especially personal information management and browser and email functions based on wireless data communication. Smartphones provide users with sufficient screen size and bandwidth, making them easy to carry around and providing a broad stage for software operation and content services. Many value-added services can be launched here, such as stocks, news, weather, transportation, commodities, and applications. Program downloads, music picture downloads, etc.
5. Tablet computer
A tablet computer is a computer that does not require a flip cover, has no keyboard, comes in different sizes and shapes, but has complete functions. Its components are basically the same as those of a laptop, but it uses a stylus to write on the screen instead of using a keyboard and mouse for input, and breaks the J-shaped design pattern of laptop keyboards that are perpendicular to the screen. In addition to having all the functions of a laptop, it also supports handwriting input or voice input, making it even more mobile and portable. Tablet computers were proposed by Bill Gates, and should at least be based on the X86 architecture. Judging from the tablet computer concept product proposed by Microsoft, a tablet computer is a PC that does not require a flip, has no keyboard, is small enough to fit into a woman's handbag, but has complete functions. . That is, Embedded Systems are application-centered, microprocessor-based, with tailorable software and hardware, adapting to the comprehensive and strict requirements of application systems on function, reliability, cost, volume, power consumption, etc. dedicated computer system. It generally consists of four parts: embedded microprocessor, peripheral hardware devices, embedded operating system and user application program. It is the fastest growing field in the computer market and is home to a wide variety of computer systems in various forms. Embedded systems include almost all electrical equipment in life, such as handheld PDAs, calculators, TV set-top boxes, mobile phones, digital TVs, multimedia players, cars, microwave ovens, digital cameras, home automation systems, elevators, air conditioners, security systems, Vending machines, cellular phones, consumer electronics equipment, industrial automation instruments and medical instruments, etc.
The core component of the embedded system is the embedded processor, which is divided into 4 categories, namely, embedded microcontroller (Micro Controller Unit, MCU, commonly known as single-chip microcomputer), embedded microprocessor (Micro Processor Unit, MPU) , embedded DSP processor (Digital Signal Processor, DSP) and embedded system on chip (System on Chip, SOC). Embedded microprocessors generally have four characteristics:
1. It has strong support for real-time and multi-tasking, can complete multi-tasking and has a short interrupt response time, so that the internal code and The execution time of the real-time operating system is reduced to a minimum;
2. It has a very powerful storage area protection function. This is because the software structure of the embedded system has been modularized, and in order to avoid errors between software modules The cross interaction between errors requires the design of a powerful storage area protection function, which is also conducive to software diagnosis;
3. Scalable processor structure to quickly expand the high performance that meets the application Embedded microprocessors;
4. The power consumption of embedded microprocessors must be very low, especially for battery-powered embedded systems used in portable wireless and mobile computing and communication equipment. In this way, the power consumption can only be mw or even μw level.