Microcomputer is referred to as microcomputer, commonly known as computer, and its exact title should be microcomputer system.It can be simply defined as:Computer hardware systemConfigure necessaryperipheralandSoftware compositionEntity of[2]。
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Microcomputer systemThere are three levels from global to local: microcomputer system, microcomputermicroprocessor（CPU）。Neither a single microprocessor nor a single microcomputer can work independently. Only a microcomputer system is completeinformation processing system Is of practical significance[2]。
The software system can be divided into system software and application software.System software refers to software that manages, monitors and maintains computer resources (including hardware and software).It mainly includes: operating system, variousLanguage processor、Database management systemAnd various tools and software.The operating system is the core of the system software, and users can only complete various operations on the computer through the operating system.Application software is a computer programmed for a certain application purposeprogram, such asWord processing software、Graphics and image processing software, Networkcommunication software, financial management software, CAD software, variousPackageetc.[3]。
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Microcomputers are characterized by small size, great flexibility, low price and convenient use.Since 1981, the United StatesIBMThe company launched the first generationMicrocomputerSince IBM-PC, microcomputers have achieved accurate andprocessing speed Fast, cost-effective, lightweight, compact and other characteristics quickly enter all fields of society, and technology is constantly updated, products are rapidly updated, from simplecomputing equipmentIt has developed into a powerful multimedia tool capable of processing various information such as numbers, symbols, words, languages, graphics, images, audio, video, etc.Today's microcomputer productsMultimedia function, hardware and software support, ease of use, etc[4]。
Server refers to some high-performance computers, which can provide services through the network.Compared with ordinary computers, they have higher requirements for stability, security, performance, etcChipset, memory, disk system, network and other hardware are different from ordinary computers.The server is the node of the network, which stores and processes 80% of the data and information on the network and plays a pivotal role in the network.The server is a high-performance computer that provides various services for client computers. Its high performance is mainly in the high speedComputing power, long and reliable operation, powerfulExternal dataThroughput capacity, etc.The composition of the server is similar to that of ordinary computers, including processors, hard disks, memorysystem bus Wait, but because it is specificnetwork applicationIt is specially customized, so that the server and microcomputer have good processing ability, stability, reliability, securityScalability, manageability, etc.Servers mainly includeNetwork server(DNS、DHCP)、Print server、Terminal Server, disk serverMail server、File serveretc.[4]。
① Desktop computer: Desktop computer is a widely used microcomputer, also called desktop computer. It is a kind of independent computer with relatively large volume. The host computer, display and other devices are generally relatively independent and need to be placed in theThe computer tableOr a special workbench, so it is named desktop.The cabinet of desktop computer has large space, good ventilation and good heat dissipation;Independent chassis is convenient for users to upgrade hardware, such as optical drive and hard disk;On/off key, restart keyUSB、audio interfaceAll are in the front panel of the chassis, convenient for users[4]。
②All in one computer: The all-in-one computer consists of a monitor, akeyboardAnd a mouse.Its chip, motherboard and display are integrated together, and the display is a computer, so the machine can be used as long as the keyboard and mouse are connected to the display.along withWireless technologyThe keyboard, mouse and display of the all-in-one computer can realizeWireless connection, there is only one machinepower cordTo a large extent, it has solved the problem of many and miscellaneous desktop cables, which has always been criticized[4]。
③Notebook computer: Notebook computer is a small, portable personal computer, usually 1-3kg in weight.It is similar to the desktop architecture, but it has better portability.In addition to the keyboard, notebook computers also provideTouch control board(TouchPad) or Pointing Stick, providing better positioning and input functions[4]。
④Pocket PC(PDA): PDA (Personal Digital Assistant) means personal digital assistant.As its name implies, it is a digital tool to assist personal work, mainly providing notesmail list, business card exchange, itinerary and other functions.It can help people work, study and play on the move.Classified by use, divided intoIndustrial PDAAnd consumer goods PDAs.Industrial PDA is mainly used in the industrial field, and the common ones areBar code scanner、RFID reader writerPOS machine;There are many consumer goods PDAs, such asIntelligent mobile phone, hand-held game console, etc[4]。
⑤tablet PC: Tablet is also called TabletPersonal Computer, referred to as Tablet PcFlat Pc、Tablet、 Slates），It is a small, portable personal computer, with touch screen as the basicinput device。It has a touch screen (also known asDigital plateTechnology) allows users to accessStylus Or a digital pen instead of a traditional keyboard or mouse.Users can use the built-inHandwriting recognition, on the screensoft keyboard、speech recognitionOr a real keyboard (if equipped with this model) can realize input[4]。
1. 4-bit and 8-bit low-grade microprocessor era (1971-1973)
In January 1971, Hoff engineers from Intel Corporation successfully developed the first 4-bit word length microprocessor chip in the worldIntel 4004, marking the advent of the first generation microprocessor and the beginning of the era of microcomputer[5]。
This stage is the era of 4-bit and 8-bit low-grade microprocessors, usually called the first generation. Its typical products are Intel 4004 andIntel 8008Microprocessors and MCS-4 and MCS-8 microcomputers composed of them respectively.The basic feature of the product at this stage is to use PMOS technology,IntegrationLow,System structureAnd command system are relatively simple, mainly usingmachine languageOr simpleassembly languageThe number of instructions is small, and it is mainly used in household appliances and simple control occasions[5]。
2. The era of 8-bit middle and high-end microprocessors (1974-1978)
This stage is usually called the second generation, and typical products include Intel'sIntel 8080/8085, Motorola MC6800 and the United StatesZilogCorporateZ80And various 8 bitssinglechip, such as 8048 of Inte, MC6801 of Motorola, Z8 of Zilog, etc.The basic feature of the product at this stage is to adoptNMOSThe process, integration degree and operation speed are improved by about 4 times and 10~15 times respectively. The instruction system is relatively complete, with typicalComputer ArchitectureAnd interruptionsDMAAnd other control functions.In addition to assembly language, BASICFORTRANetc.high-level languageAnd correspondingInterpreterandCompilerIn the later stage, the operating system also appeared, such asCP/MThe popular operating system at that time[5]。
3. 16 bit microprocessor era (1978-1984)
This stage is usually called the 3rd generation.In June 1978, Intel Corporation launched a 16 bit word length microprocessor chip with a main frequency of 4.77MHzIntel 8086。8086 microprocessorThe birth of marked the advent of the third generation microprocessor.Typical products in this stage include Intel 8086/8088, 80286, Motorola M68000, Zilog Z8000 and other microprocessors.It is characterized by the adoption ofHMOSThe process, integration and operation speed of the second generation are all improved by oneOrder of magnitude。The instruction system is more abundant and perfect, and theMultilevel interrupt, variousAddressing mode, segmentstorage structure , hardware multiplication and division components, and software system[5]。
The famous microcomputer products of this period areIBMCorporatepersonal computerThe IBM PC introduced in 1981 uses 8088 CPU.Then in 1982, the extended personal computer IBM-PC/XT was launched, which expanded the memory and added aHard drive。In 1984, IBM launched a 16 bit enhanced personal computer with 80286 processor as the core IBM-PC/AT。Because IBM adopted the strategy of opening technology when developing PC, PC became popular all over the world[5]。
4. 32-bit microprocessor era (1985~1992)
This stage is usually called Generation 4.In October 1985, Intel Corporation launched the 80386DX microprocessor, marking the entry of the 32-bitdata busTimes.Typical products in this stage include Intel's 80386/80486, Motorola's M68030/68040, etc.It is characterized by HMOS orCMOS process, integration up to 1 milliontransistor/Slice, with 32 bitsAddress lineAnd 32-bit data bus.Six million instructions can be completed per second.The function of microcomputer has reached or even exceededSupercomputer, fully competentMultitasking、Multi userJob for.During the same period, other microprocessor manufacturers (such asAMD, TEXAS, etc.) also launched chips of 80386/80486 series[5]。
This stage is usually called the 5th generation.The typical product is IntelPentiumSeries chips and compatible AMD K6 series microprocessor chips.In this stage, the product adoptsSuperscalarinstructionsPipeline structureWith independent instructions and dataCache。along withMMXThe emergence of (Multi media eXtend) microprocessor has made the development of microcomputer reach a higher level in networking, multimedia and intelligence.In March 2000, AMD and Intel respectively launched theAthlonAnd Pentium III.In November 2000, Intel launched the Pentium Ⅳ microprocessor, with the integration of 42 million transistors per chip, 1.5GHz, 400MHzFront end bus, use brand newSSE2 Instruction Set。In November 2002, Intel launched the Pentium Ⅳ microprocessor with a clock frequency of 3.06GHz. The microprocessor is still developing and its performance is improving[5]。
In 2001, Intel released the first 64 bit productItanium（itanium ）Microprocessor.In April 2003,AMDThe company launched Opteron based on 64 bit operation（Opteron ）Microprocessor.In September 2003, Athlon of AMD（Velociraptor）The advent of microprocessors marks64-bit computing The arrival of the times[5]。
Word length refers to that the computer computing unit can process at the same timebinary dataThe number of digits of.The longer the word, if used asStore data, the higher the computing accuracy of the computer;If it is used as a storage instruction, the processing power of the computer will be stronger.Generally, the word length is always an integer multiple of 8, such as 8, 16, 32, 64 bits, etc.Intel 486 andPentium 4All computers belong to 32-bit computers[6]。
clock speed
The clock frequency refers to the CPU'sclock frequencyIt determines the speed of the computer to a certain extent.Main frequency in megahertz（MHz）In general, the higher the dominant frequency, the faster the speed.Due to the rapid development of microprocessors, the main frequency of microprocessors is also increasing[6]。
Operation speed
ComputerOperation speedIt usually refers to the ability of every secondExecute instructionsThe number of, usually millions of times/second（MIPS, MillionInstructions Per Second).This indicator can more intuitively reflect the speed of the machine[6]。
storage capacity
storage capacity UsuallyMemoryCapacity and external memory capacity, here mainly refers to the capacity of internal memory.obviously,Memory capacityThe larger the machine, the larger the program it can run and the stronger the processing power.In particular, the current multimedia PC applications are mostly involved in image information processing, which requires more and more storage capacity. Even without enough memory capacity, some software cannot run.The memory capacity of most microcomputers has reached 4GB[6]。
Access cycle
Internal storageAccess cycleIt also affects the whole computersystem performance One of the main indicators of.In brief, the access cycle is the time required for the CPU to access data from the internal memory.Memory access cycle is between 7-70ns[7]。
