1 copyright 2003 the mcgraw-hill companies, inc. 66 chapter the system unit （系统单元）...

11Copyright 2003 The McGraw-Hill CompCopyright 2003 The McGraw-Hill Companies, Inc.anies, Inc.

6666CH

AP

TE

R

The System Unit

（系统单元）

computing ESSENTIALS

Copyright 2003 The McGraw-Hill CompCopyright 2003 The McGraw-Hill Companies, Inc.anies, Inc.

22

CompetenciesCompetencies （（能力）能力）

System unit types 类型 Coding 编码

major system unit components 主要构成 system boards,microprocessors,memory 主板、处理器、内存System clock,expansion slots,boards,bus lines系统时钟、扩展

槽、插板、总线 Ports,cables and power supply 端口、电缆、电源



33

System Unit TypesSystem Unit Types （（系统单元类型）系统单元类型）

• System Unit– Houses electronic

components– Basic components

• System board• Microprocessor• Memory• Expansion cards• Expansion slots

• Types of System Units

– Desktop

– Notebook

– Tablet PC

– Personal Digital

Assistant



44

Desktop UnitsDesktop Units （（台式机）台式机）

• Non-portable 非移动式

• Input/Output devices

located outside the

system cabinet 输入输

出设备位于系统箱外



55

Notebook UnitNotebook Unit （（笔记本）笔记本）• Portable

• Monitor attached by

hinges 显示器可开合

• Keyboard and pointing

devices integral to the

system unit 键盘和指示设备集成于系统单元



66


Tablet PC system unit （平板电脑）

Similar to notebook 与笔记本相似

Highly portable 高移动性

Support the use of a stylus or pen

支持记录笔


77

PDA UnitsPDA Units （（掌上电脑）掌上电脑）

• Smallest system unit

• All input/output and

secondary storage

devices integral to the

system unit



88

Electronic Data & InstructionsElectronic Data & Instructions（（电子数据和指令）电子数据和指令）

• Binary System

– 0s and 1s

– Each 0 or 1 is a bit

– 8 bits = 1 byte



99

Binary Coding SchemeBinary Coding Scheme （（二进制编码方案）二进制编码方案）

• American Standard Code for Information

Interchange (ASCII)

• Extended Binary Coded Decimal Interchange

Code (EBCDIC)

• Unicode



1010

ASCIIASCII （（美国信息交换标准码）美国信息交换标准码）• Widely used in

microcomputers • 1 byte = 1 character• Examples

– Letter R is represented by 0101 0010

– Number 3 is represented by 0011 0011

– Character % is represented by 0010 0101



1111

EBCDICEBCDIC （（扩充二进制编码的十进制交换码）扩充二进制编码的十进制交换码）

• Developed by IBM

• Used in mainframe computers

• 1 byte = 1 character

• Examples

– Letter R is represented by 1101 1001

– Number 3 is represented by 1111 0011

– Character % is represented by 0110 1100



1212

UnicodeUnicode （（统一字符编码标准）统一字符编码标准）

• Developed by Unicode, Inc. with support from

Apple, IBM, and Microsoft

• Used to support international languages such

as Japanese and Chinese

• 2 bytes = 1 character



1313

System BoardSystem Board （（系统板）系统板）

• Connects all components

连接所有部件

• Data path between

devices 设备间的数据通道

• Also called the main board

or motherboard 也叫主板



1414

System Board ComponentsSystem Board Components（（组成）组成）

• Sockets 插孔Connection points for small specialized electronic parts小电子部件的连接点

• Chips 芯片Tiny circuit boards etched into silicon wafer 蚀刻成电路板后的硅晶片

• Carrier Package芯片封装后的集成电路块

• Slot connection point for specialized cards or circuit boards



1515

MicroprocessorMicroprocessor （（微处理器）微处理器）

• The “brains” of the computer system• Location of the Central Processing Unit

(CPU) • Chip capacity expressed in word size

–16 bit, 32 bit, 64 bit–Larger the word size

faster the computer



1616

CPUCPU （（中央处理器）中央处理器）• Control unit

– Directs the movement of electronic signals between memory and the ALU

• Arithmetic-logic unit (ALU)

– Arithmetic operations• Fundamental math operations

– Logical operations• Compares data



1717

Microprocessors chipMicroprocessors chip （（微处理器芯微处理器芯片）片）

• CISC chip– Complex Instruction Set Computer

– Intel’s Pentium, Itanium chips, AMD Athlon, Hammer chips

• RISC chip– Reduced Instruction Set Computer

– Simpler, cheaper then RISC chips

– Motorola PowerPC chip, DEC Alpha chip



1818

Other MicroprocessorsOther Microprocessors （（其他微处理其他微处理器）器）

• Graphics coprocessors

handle 2-D and 3-D graphics images

• Parallel processors

work with one or more other parallel processor chips and

process their respective parts simultaneously

• Smart Cards

– Plastic card that contains a specialized processor chip

– Stores more than 80 times data of conventional magnetic

strip

– Used in credit cards, identification cards, phone cards



1919

MemoryMemory （（内存）内存）• Holding area for data and

instructions

• Three types– Random-access memory

(RAM)

– Read-only memory (ROM)

– Complementary metal-oxide semiconductor (CMOS)



2020

Random-access MemoryRandom-access Memory （（随机存储随机存储器）器）

• Holds currently running programs and data being processed by the CPU

• Volatile storage

– Contained data is lost when computer is turned off

• Virtual memory

– RAM pages saved to secondary storage until needed by CPU



2121

Special RAM TypesSpecial RAM Types （（特殊特殊 RAMRAM 类型）类型）

• RAM cache– Frequently accessed data– Acts as high-speed, temporary holding area

between CPU and RAM– Faster processing results

• Flash RAM– Data is retained even if power disrupted– Commonly used in cell phone, digital cameras



2222

Read-Only MemoryRead-Only Memory （（只读存储器）只读存储器）

• Programs and data are permanently encoded

• CPU can only retrieve data

• Nonvolatile, cannot be changed by the user

• Used for storing special instructions, such as

computer startup



2323

Complementary Metal-Oxide Complementary Metal-Oxide SemiconductorSemiconductor （（互补金属氧化物半导互补金属氧化物半导

体）体）• Provides the flexibility and expandability for a

computer system

• Saves data even when computer power is shut off

• Contents can be changed by the user

• Stores information such as amount of memory, type of keyboard, mouse



2424

Memory MeasureMemory Measure （（内存度量标准）内存度量标准）

UnitUnit CapacityCapacity

Kilobyte (KB) 1,000 bytes

Megabyte (MB) one million bytes

Gigabyte (GB) one billion bytes

Terabyte (TB) one trillion bytes



2525

System ClockSystem Clock （（系统时钟）系统时钟）

• Special chip that produces precise

electrical impulses

• Used to coordinate and synchronize

computer operations

• Expressed in megahertz or gigahertz

• Faster clock speed, faster computer



2626

Expansion SlotsExpansion Slots （（扩展槽）扩展槽）

• Slots provided to add expansion cards to the

system unit

• Used on open architecture system boards



2727

Expansion CardsExpansion Cards （（扩展卡）扩展卡）

• Expansion cards used to connect to

devices outside the system unit

• Controller cards, Adapter cards, Interface

cards, plug-in boards

• Usually have ports to connect the card to a

device outside the system unit



2828

Types of Expansion CardsTypes of Expansion Cards （（扩展扩展卡类型）卡类型）

• Network interface cards (NIC)

• Modem cards• Sound cards• Video cards• SCSI adapter• TV tuner cards• PCMCIA cards



2929

““Plug and Play”Plug and Play” （（即插即用）即插即用）

• Hardware and software standards

– Makes system expansion easy for the

user

• Automatically installs drivers and system

configuration

– System unit recognizes the new device



3030

Bus LinesBus Lines （（总线）总线）• More lines, the faster

data can travel– 64 bit data bus is

faster than a 32 bit

• Data pathways that link parts of the CPU together and components to the CPU



3131

Principal Bus ArchitecturesPrincipal Bus Architectures （（主要总主要总线结构）线结构）

• Industry Standard Architecture (ISA)

• Peripheral Component Interconnect (PCI)

• Advanced Graphic Port (AGP)

• Universal Serial Bus (USB)

• High performance Serial Bus (HPSB)



3232

ISA BusISA Bus （（工业标准结构总线）工业标准结构总线）

• Developed by IBM for personal computers

• Slow

– Originally 8 bit, later expanded to 16 bit

– Still used by some expansion cards

• Replaced by PCI bus in the near future



3333

PCI BusPCI Bus （（周边元件扩展接口总线）周边元件扩展接口总线）

• Originally developed to meet demands of

graphical user interfaces

• High speed

– 32 bit or 64 bit

• Widely used to connect CPU, memory, and

expansion cards



3434

AGP BusAGP Bus （（加速图形接口总线）加速图形接口总线）

• Dedicated bus for acceleration of graphics

performance

• Replacing the PCI bus for transfer of video

data



3535

Other Bus TypesOther Bus Types （（其他总线类型）其他总线类型）

• USB（通用串行总线）– Connects directly to the PCI bus on the

motherboard– Supports external devices without

inserting expansion cards for each device• HPSB（高性能串行总线）

– FireWire– Similar to USB but faster



3636

PortsPorts （（接口）接口）

• Four common port types– Serial

– Parallel

– USB

– FireWire


• Sockets that connect external devices to the system unit


3737

Serial & Parallel PortsSerial & Parallel Ports （（串行和并行接串行和并行接口）口）

• Serial Port

– Data sent one bit at a time

– Good long distance transmission of data

• Parallel Port

– Data sent 8 bits simultaneously

– Used for short distances



3838

USB and HPSB PortsUSB and HPSB Ports （（ USBUSB 和和HPSB HPSB 接口）接口）

• USB Port– Replacing serial and parallel ports – Faster– Each port can support

more than one device• HPSB Port

– FireWire ports– Faster then USB ports



3939

CablesCables （（接线）接线）

• Connect Input/Output devices

– Mouse

– Keyboard

– Printer

– Monitor

• Newer cables– AGP

• graphics monitor

– USB• joy stick; scanner

– HPSB• video camera



4040

Look to the FutureLook to the Future （（前景）前景）

• Wireless Technology and PDAs

• Personal wearable computer

– POMA®

• Wireless pointing device, head mounted display

• Developed by Xybernaut Corporation

• Currently being evaluated for use in airport security


1 copyright 2003 the mcgraw-hill companies, inc. 66 chapter the system unit （系统单元）...

Documents