计算机文化基础双语课件-Chapter2-computer-hardware

1、Chapter 2 Computer HardwareHardware SystemSystem unit CPU (program control unit + Arithmetic Logic unit) Memory & Storage (External Memory)InputOutputChapter 2 Computer Hardwar2.1: An Overview2.2 : Microprocessors 2.3 : Memory 2.4 : Storage Devices2.5 : Input and Output DevicesContents2.1: An Overvi

2、ewContentsKM chart of Chapter TwoKM chart of Chapter Two2.1 An Overview of the Computer Hardware键盘主机/System unit鼠标电源开关光盘驱动器显示器软盘驱动器Whats a personal computer system?What are the components of a typical PC?2.1 An Overview of the ComputSystem UnitKeyboardMouseHard disk driveCD and DVD driversOther stor

3、ageSound systemDisplay system: graphics card monitorNetwork and Internet accessprinterSystem Unit输入设备存储器输出设备运算器控制器数据流控制流 Hardware System输入设备存储器输出设备运算器控制器数据流控制流 HardwaInformation processing cycleInformation processing cycle 2.2: MicroprocessorsWhat is a microprocessor? is an integrated circuit design

4、ed to process instructions P27 of E 2.2: MicroprocessorsWhat is Circuits and chipsWhats a computer chip?the terms computer chip, microchip, and chip originated as technical jargon for integrated circuit. integrated circuit is an super-thin slice of semiconducting material packed with microscopic cir

5、cuit elements, such as wires, transistors, capacitors, logic gates, and resistors.(p28 )Circuits and chipsWhats a com Motherboard (circuit board) many chips are housed on motherboard. processor chip;computer memory; system bus; Motherboard (circuit board) pCPUs functions1)Executes instructions to pr

6、ocess data, for example, perform arithmetic, sort list, format document.2)Retrieves instructions and data from RAM, after processing instructions, places the results back into RAM.CPURAMInstructionsDataCPUs functionsCPURAMInstructiProcessor LogicPrograms and instruction sets:How do digital devices p

7、rocess data?The data is manipulated under the control of a computer program.The human-readable version of a program is called source code.Processor LogicPrograms and inHow does source code get converted?The procedure for translating source code into 0s and 1s can be accomplished by a compiler or an

8、interpreter.A compiler converts all the statements in a program in a single batch, and the resulting collection of instructions, called object code, is placed in a new file.(p30 f1-34)Digital processingHow does source code get conve“语言”是人机交流的工具程序是用“语言”写成的计算机可以识别的“文章”用于编写计算机可以执行的程序的语言称为程序设计语言机器语言机器指令

9、0 或 1 代码 与语言习惯差别很大难以学习和记忆依赖机器的类型汇编语言用助记符代替机器代码；用变量代替各类地址克服记忆的难点其他与假期语言类似高级语言类似数学语言、接近自然语言、具有通用性和可移植性、不依赖具体的计算机类型“语言”是人机交流的工具机器语言机器指令与语言习惯差别很大难高级程序的编译运行方式可执行程序编译程序高级语言程序目标程序连接程序编译连接Compiler高级程序的编译运行方式可执行程序编译程序高级语言程序目标程序An interpreter converts and executes one statement at a time while the program is

10、running.执行解释程序高级语言程序解释Interpreter高级程序的解释运行方式An interpreter converts and exWhat does the conversion process produce?Instruction set: collection of preprogrammed activitiesis designed to be general purpose so that programmers can use it in creative ways for the wide variety of tasks performed by all k

11、inds of digital devices.Instruction: each instruction has a corresponding sequence of 0s and 1s. E.g add-00000100Machine language: can be directly executed by the processors circuitryDigital processingWhat does the conversion proceA machine code instruction has two parts: the op code and the operand

12、.Eg: instruction: add 1 00000100 00000001Digital processingOp codeOperandP31 f1-36A machine code instruction has指令的概念指令：计算机能够识别并执行的“操作命令”指令一般由操作码和操作数组成操作码 目标操作数 源操作数操作码 操作数表示功能（操作）表示操作的对象指令的概念指令：计算机能够识别并执行的“操作命令”操作码 Components: Program ControlCentral Processing UnitArithmetic LogicUnit (ALU)Main mem

13、ory I/OEquip-mentregisterProcessor logicComponents: Program ControlCeProcessor logicWhat happens when a computer executes an instruction?(p30)Fetch instruction 4.Increment pointer to the next instruction3. Execute instruction2. Interpret instructionProcessor logicWhat happens whCPU ArchitectureALUCo

14、ntrol unitA CPU have two main partsALU performs: arithmetic operations addition, subtraction, multiplication, division; logical operations AND, OR, Exclusive-OR, NOT.CPU ArchitectureALUControl uniCPU Program control unit（程序控制单元） -Control the operation of CPU; Arithmetic and logic unit (ALU) （运算器） -P

15、erform data processing; Registers (寄存器组） -Internal storage; CPU interconnection （CPU内部总线） -Provides communication among them.CPU Program control unit（程The Control Units function ( p.32) -Retrieves an instruction from RAM and puts it in the instruction register. -The RAM address of the instruction is

16、 kept in the instruction pointer. -When the instruction has been executed, the address in the instruction pointer changes to the RAM address of the next instruction to be executed.Control UnitInstruction pointer Instruction RegisterM1ADD two numberRAMAddress M1Address M2Address M3M2MUL two numberThe

17、 Control Units function ( CPU Performance Factors- Moore law- “A chain is only as strong as its weakest link”. A high-performance processor with a slow hard disk, no disk cache, and a small amount of RAM is likely to be slow at tasks such as starting programs, loading large amount of data, printing

18、and scrolling through long document.CPU Performance Factors- CPU speed is influenced by clock speed, bus speed, word size, cache size, instruction set, number of cores, and processing techniques. Specifications for these factors allow you to compare different CPUs.CPU Performance Factors- CPU speed

19、is influenced by (Microprocessor Clock microprocessor clock- a timing device that sets the pace for executing instructionsMegahertz (MHz) - a million cycles per secondGigahertz (GHz) - a billion cycles per second-Instruction cycle (the time to complete an instruction cycle) is measured in megahertz

20、(million of cycles per second or MIPS)(CPU 的主频）;(Microprocessor Clock -If all other specifications are identical, higher MHz ratings faster processing -The original IBMPC is 4.77MHz, todays exceed GHz. -If all other specifications FSBFront Side Busrefers to the circuitry that transports data to and

21、from the microprocessor.A fast front side bus moves data quickly and allows the processor to work at full capacity.200MHz1250MHzFSBFront Side Busrefers to thWord Size（字长） The number of bits that the CPU can manipulate at one time.-Word size is based on the size of the register in CPU and the number

22、of data line in the bus; For example, a CPU with a 8-bit word size is referred to as an 8-bit processor.-Larger word size process more data in each instruction cycle increased performanceWord Size（字长）-The first microcomputers contained 8-bit microprocessor, but todays computers contain 32-bit or 64-

23、bit microprocessor.-The first microcomputers contCache (高速缓存) Sometimes called “RAM cache” or “cache memory”; -It is special high speed memory that speeds access to data from RAM. -As you begin a task, the computer loads the possible data into the cache area. The CPU first checks to see if the requi

24、red data is in the cache; -If all other factors are same, cache means faster processing. Cache (高速缓存)Instruction Set (P.31) -Instruction set is the complete collection of instructions which are used by a particular type of central processor. -Two of the main approaches to the design of microprocesso

25、rs are the Complex Instruction Set Computer(CISC) and the Reduced Instruction Set Computer(RISC).Instruction Set (P.31)Number of coresMore cores usually produce faster performance multiple cores can run multiple instructions at the same timeNumber of coresMore cores usua Pipelining processing -Compu

26、ters with a single processor execute instructions “serially”, that is, one instruction at a time. Instruction cycle fetch-decode-execute-output- Pipelining technology: the processor can began executing an instruction before it completes the previous instruction; - Pipelining speeds up processing. Pi

27、pelining processingControlUnitRegisters(Instruction2)Accumulator(Instruction1)RAMInstruction1Instruction2Instruction3The controlUnit decodesInstruction3The data for Instuction2 moves into a registerInstruction1 is completed1234ControlRegistersAccumulatorRAM Parallel Processing-A computer has more th

28、an one processor and can execute multiple instructions at the same time; This is called parallel processing;-A computer that is capable of parallel processing is called a parallel computer or “Non-von Neumann machine”;-It is the simultaneous use of several processors to perform a single job. A job m

29、ay be split into tasks each of which may be processed by any available processor. Parallel ProcessingProcessor1Processor2Processor3ControlUnit(4)Data (1)Instruction(2)(3)ResultProcessor1Processor2Processor31)Instructions are queued and waiting to enter the CPU.2)The control unit sends an instruction

30、 to the next available processor.3)Each processors completes its assigned instruction. Because the processors finish at different times, the results might not be in sequence.4)The result are places in the correct order out of the CPU.1)Instructions are queued and Data bus: electronic pathway or circ

31、uit on which data travel from one location to another within the computerAddress bus:Control bus:Data bus:4 major types of memory: random access memory (RAM)read-only memory (ROM)EEPROM cache memoryvirtual memory2.3 Memory4 major types of memory: 2.3 Mrandom access memory (RAM)Capacitors hold electr

32、onic signal for data RAM Address most RAM is volatile(易失性)random access memory (RAM)1) random access memoryCapacity Measured in megabyte 256M-2G Speed today 8 nanoseconds (one billionth of second)(毫微秒）.Configuration（构造） RAM is typically configured as small circuit boards called DIMMs (dual in-line m

33、emory modules).1) random access memory 2) Read-only Memory（ROM） -The instructions in ROM are permanent; -ROM contains a small set of instructions called the ROM BIOS(basic input/output system), tell the computer how to access the disk drives and other peripheral devices; -When the computer is just t

34、urned on, RAM is empty, the CPU executes the instructions in ROM BIOS that search the disk drive for the main operating system files, then load the files into RAM so that they can be used during the reminder of the computing session; 2) Read-only Memory（ROM）-Software in ROM is fixed during manufactu

35、re, but there are other ways of putting programs and data into ROM;-Including PROM, EPROM, etc. PROM(Programmable Read-only Memory) is a type of ROM which is manufactured as an empty storage array and is later permanently programmed by the user. -Software in ROM is fixed duri EPROM(Erasable PROM) is

36、 a type of PROM whose data can be erased by a special process so new data can be written as if it were a new PROM.EEPROM(Electrically Erasable PROM) - no power to hold data - replace CMOS technology(require a small battery) EPROM(Erasable PROM) is a ty3) Cache Memorycache is a used by the central pr

37、ocessing unit (CPU) to reduce the average time to access memorysmaller, faster first check in the cache When the processor needs to read from or write to a location in main memory3) Cache Memorycache is a4) Virtual Memory（虚拟内存） -A computers ability to use disk storage to simulate RAM is called virtu

38、al memory; -Allows computers without sufficient amounts of real memory to run large programs, data files; -Not as fast as RAM. Disk access time is 10 milliseconds; -Data becomes inaccessible if power fails, because the instructions that direct the computer to the location of virtual memory are store

39、d in RAM.4) Virtual Memory（虚拟内存）Memory HierarchyMemory HierarchyHow computers store mass data? Study storage technology: electronic, magnetic, optical -data storage life spanUse popular software utilities to locate, organize, change, search the data 2.4: Storage Devices (external storage)How compute

40、rs store mass data?1) Storage basicsphysical storage - storage medium (media) logical storage - files , folders the data for a single file can be scattered all over the surface of storage medium storage terminology 1) storage medium: substance that contains data 2) storage device: mechanical apparat

41、us that record and retrieve data from storage medium. 3) read, load, open write, save 2.4 : Storage Devices 1) Storage basics2.4 : Storage2.4.2 Magnetic Storage Technology magnetic storage (hard disk, floppy disk, tape storage) (P36 of E.) mechanism: store data by magnetizing microscopic particles o

42、n a disk or tape surface.2.4.2 Magnetic Storage Technolflexibility for editing data and reusing areas of storage medium.data maintenance : 1) place magnetic medium in a clean environment. 2) recopy the data every 2 years. 2.4.2 Magnetic Storage Technology2.4.2 Magnetic Storage TechnolWhy are hard di

43、sk drives so popular?1) lots of storage capacity2) fast access to files3) economical 2.4.2 Magnetic Storage Technology2.4.2 Magnetic Storage TechnolHard Disk Storage A hard disk platter is a flat, rigid disk made of aluminum or glass and coated with a magnetic oxide. A hard disk is one or more platt

44、er and their associated read-write heads, typically 3 inches in diameter. Several hundreds GB capacity (40 500GB); Random access; Continually in motion, so faster access to file than floppy (6 to 11 ms).Hard Disk Storage扇区读写磁头柱面磁道各盘片上同一位置的磁道构成一个柱面。cylinder扇区读写磁头柱面磁道各盘片上同一位置的磁道构成一个柱面。cyFloppy Disk St

45、orage p.68 - 3 inch, 5 inch, zip disk; -Disk may have data stored on one side or on both sides (DSD). - 3 high density 1.44MB ; Floppy Disk Storage p.68 - Takes about 0.5s (3 inch) to spin it to maximum speed and then find a specific sector that contains data; -A zip drive(100MB) is about 20 times f

46、aster; - Random access; - Newer technologies are decreasing the use of floppy disks, using CD-ROM or DVD-ROM instead. - Takes about 0.5s (3 inch) CD(compact disc) technology was originally designed to hold 74 minutes of recorded musicDVD(digital video disc or digital versatile disk) is a variation o

47、f CD technology, 4.7Goptical storage (CD and DVD) (P69 of E.) stores data as microscopic light and dark spots on the disk surface1) pits(凹) and lands(凸) of medium is interpreted as 1s and 0s. 2.4.3 Optical Storage technologyDark spots -pits - 1 CD(compact disc) technology wa optical technology (CD a

48、nd DVD) 2) use a low-power laser beam to read data 3) less susceptible than magnetic storage 易受影响2.4: Storage Devices 2.4.3 Optical Storage technology optical technology (CD and storage deviceThe criteria（标准） for comparing storage devices: Versatility (多面性） -Devices can access data from several diff

49、erent media.Durability（耐用性） -More durable technologies are less susceptible to damage that could cause data loss.Capacity -Higher capacity is almost always preferred.Speed -Measured by its access time and data transfer rate. Fast storage devices are preferred.storage device where the speed is determ

50、ined by: Access time average time it takes a computer to locate data on the storage medium and read it.(1)Random access (also called “direct access”) “Jump” directly to the track or sector that holds the requested data.(2)Sequential access Read through the data from the beginning of the tape. Data t

51、ransfer rate the amount of data that a storage device can move from the storage medium to the computer per second. where the speed is determin CD-ROM Technology-CD-ROM(Compact Disc Read-only Memory) contains data when it was manufactured. -Holds up to 680MB;-Read-only;-Not susceptible to humidity,fi

52、ngerprints,dust or magnets;-relatively inexpensive to manufacture, make it an ideal way for SW publishers to distribute large programs and data files.-The speed has increased. CD-ROM TechnologyCD-R (compact disc-recordable)-Uses a CD-R drive, recording data on CD-R disks;-Allow to record data in mul

53、tiple sessions;-Most of todays optical drives provide multi session support, but not that manufactured before 1998;-Slow, take from 20 to 60 minutes to record a full CD-R;-You cannot delete or change data once it has been recorded.-The disks produced on a CD-R device can be used on CD-ROM or DVD dri

54、ve.CD-R (compact disc-recordable)CD-RW (compact disc-rewritable)-Allows you to write data on a CD-RW disks, then change that data;-Most of todays optical drives now read CD-RW disk;-Process of accessing, saving and modifying data on CD-RW disk is relatively slow. It is not yet an acceptable substitu

55、te for a hard disk.CD-RW (compact disc-rewritable DVD (digital video disc) Being designed to provide enough storage capacity for a full-length movie; Like CD-ROM, DVD-ROM does not allow you to add or change the data on the disk, but DVD-R, DVD-RW do. 4.7GB storage; DVD drive can read data from CD-RO

56、M, CD-R and CD-RW disks, but DVD disk cannot be read by CD-ROM, CD-R or CD-RW drives; Prediction: eventually these devices will be replaced by a single DVD device. DVD (digital video disc) What is solid state storage? Stores data in erasable, rewritable circuitryFlash memoryWidely used in portable c

57、onsumer devicesdigital cameras, MP3, cell phonesPortable , fast access to dataideal for mobile devices and transporting data2.4: Storage Devices 2.4.4 Solid State Storage What is solid state storage? How does solid state storage work?gridwork or circuitryTransistors (晶体管) act as gatesgates open- “1”

58、bitvery litter power to open or close the gateideal for battery-operated devices (digital cameras)Non-volatile (chip retains the data)Fast access to dataDownside Capacity (less than), cost (higher than that for magnetic or optical storage)2.4: Storage Devices 2.4.4 Solid State StorageHow does solid

59、state storage wWhat is a USB flash drive?USB flash drives are often designed with different casesWhat is a USB flash drive?USB What is a USB flash drive?A USB flash drive is a portable storage device that plugs directly into a computers USB port using a built-in connector(Figure 2-16).USB flash driv

60、es have capacities ranging from 16MB to 8GB.Maximum data transfer speeds of about 100Mbps most commonly operate in the range of 18-28 Mbps2.4: Storage Devices 2.4.4 Solid State Storage What is a USB flash drive?2.4Advantages and disadvantagesFloppy diskCD-RWDVD+RWFlash driveHard drive(internal)Hard