Chapter 6
The System Unit
College of Computer and Information Science
Key Words & Terms
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AC adapter:交流适配器
accelerated graphics port (AGP):加速图形端口
analog:模拟信号
Arithmetic Logic Unit (ALU):算术逻辑单元
arithmetic operation:算术运算
ASCII:一种八位键盘符号编码
binary coding scheme:二进制编码方案
binary system:二进制系统
bit:二进制位
bus:总线
bus line:总线
bus width:总线宽度
byte:字节
cable:电缆
cache memory:高速缓冲存储器
carrier package:载体
Central Processing Unit(CPU):中央处理器
chip:芯片
clock speed:时钟速度
complementary metal-oxide semiconductor (CMOS):互补金属氧化半导体
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Key Words & Terms
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computer technician：计算机技术人员
control unit:控制单元
coprocessor: 协处理器
desktop system unit:台式机系统单元
digital:数字式
dial-core chip：双核芯片
EBCDIC:一种八位键盘符号编码
expansion bus:扩展总线
expansion card:扩展卡
expansion slot：扩展槽
FireWire bus:火线总线
FireWire port:火线端口
flash memory:闪存
graphics card:图形卡
graphics coprocessor:图形协处理器
handheld computer system unit:掌上型计算机系统单元
industry standard architecture(ISA):工业标准体系结构
Infrared Data Association (IrDA)：红外线传输器标准组织
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Key Words & Terms
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integrated circuit:集成电路
laptop:膝上型计算机
logical operation:逻辑运算
memory：内存
microprocessor：微处理器
modem card: modem卡
motherboard:主板
Musical Interface Digital Interface （Music Instrument Data
Interface, MIDI）:乐器数字界面
network adapter card:网络适配卡
network interface card (NIC):网络接口卡
notebook system unit:笔记本电脑系统单元
parallel port:并行端口
parallel processing:并行处理
PC card: PC卡
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Key Words & Terms
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PCI Express : 快速PCI
peripheral component interconnect (PCI) :外围设备连接端口
Personal digital assistant (PDA):个人数字化助理
Plug and Play:即插即用
port:端口
power supply unit:供电单元
processor:处理器
random-access memory (RAM):可读写内存
read-only memory (ROM):只读内存
RFID tag：RFID 标签
semiconductor:半导体
serial port:串行端口
silicon chip:硅芯片
slot:插槽
smart card:智能卡
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Key Words & Terms
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socket:插口
sound card：声卡
system board:系统板
system bus:系统总线
system cabinet:机箱
system clock:系统时钟
system unit:系统单元
tablet PC system unit: tablet PC 系统单元
TV tuner card:电视调协卡
unicode:十六位字符编码
universal serial bus (USB):通用串行总线
universal serial bus (USB) port:通用串行总线端口
virtual memory:虚拟内存
word:字
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Competencies (1 of 2)
• Describe the four basic types of system units
• Discuss how a computer uses binary codes
to represent data in electronic form
• Describe each of the major system unit
components
• Discuss microprocessors, including
specialty processors
• Describe the different types of memory
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Competencies (2 of 2)
• Discuss expansion slots and boards
• Describe the five principal types of
expansion buses
• Discuss the four standard ports
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Introduction
Speed, capacity, and flexibility determine the
power of microcomputers. Knowledge of a
computer’s power allows you to make good
buying decisions and to determine if your
current system will run new applications.
Competent end users need to understand the
basic principles of how microcomputers are
put together. These principles will be
covered in this chapter.
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System Unit
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System Unit Types
• Desktop System Units
• Notebook System Units
• Tablet PC System Units
• Handheld Computer
System Units
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Electronic Data and Instructions
• Data and instructions are represented
electronically
• Two-state system or Binary System
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Off/on electrical states
Characters represented by 0s (off) and 1s (on)
Bits
Bytes
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Binary Coding Schemes
• Three types of binary coding schemes
– ASCII - American Standard Code for Information
Exchange
– EBCDIC - Extended Binary Coded Decimal
Interchange Code
– Unicode – handles languages with large numbers
of characters
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System Board
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Connects all components
Allows communication between devices
Main board or motherboard
Circuit board
electronic components
– Sockets
– Slots
– Bus lines
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Microprocessor
• Central Processing Unit (CPU)
• Two Basic Components
– Control unit
– Arithmetic-logic unit (ALU)
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Microprocessor Chips
• Chip capacities are expressed in word sizes
• Two Recent Significant Developments
– 64-bit processors
• Becoming more commonplace
• Windows XP Professional X64 Edition
– Dual-Core Chips
• Can provide two separate and independent CPUs
• Parallel processing
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Specialty Processors
• Coprocessors
– Designed to improve specific computing operations
– Graphics coprocessors
• Smart cards
– Credit card sized with an embedded chip
– Used by many universities
• RFID tags
– Information chips
– Used for tracking purposes
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Memory
• Holding area for data, instructions, and
information
• Memory is contained on chips connected to
the system board
• Types of memory chips
– RAM
– ROM
– CMOS
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RAM
• Random Access Memory (RAM) chips hold
the program and data
– Cache memory or RAM cache
– Flash RAM or flash memory
• Other types of RAM
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DRAM
SDRAM
DDR
Direct RDRAM
Return
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ROM
• Read-only memory (ROM) chips are not
volatile and cannot be changed by the user
• CPU can read, or retrieve data and programs
but the computer cannot write
• Contain special instructions
– Needed to start a computer
– Give keyboard keys their special capabilities
– Put characters on screen
Return
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CMOS
• Complementary metal-oxides semiconductor
(CMOS) chips provide flexibility for a
computer system
• Contains essential information every time the
computer is turned on
– Date and time
– Amount of RAM
– Type of keyboard
• Content can be changed to reflect changes in
the computer system
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System Clock
• Important measurement indicating speed
– Located on a small chip
– Produces electrical beats
• Synchronizes operations
• Expressed in gigahertz (GHz)
(billions of beats per second)
• Faster clock speed, faster computer
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Expansion Slots and Cards
• Allow for new devices to be added
– Open architecture
– Slots provide for expansion
• Expansion cards are also called …
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Plug-in boards
Controller cards
Adapter cards
Interface cards
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Commonly Used Expansion
Cards
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Graphics cards
Sound cards
Modem cards
Network interface cards (NIC)
PC cards (PCMCIA cards)
TV tuner cards
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TV Tuner Cards And
Video Clips
• Allows you to view your favorite TV shows
while running other applications such as
Excel
• Video can be captured to a file, added to a
Web page, attached to an email, or added to
a class presentation
• Relatively inexpensive and
easy to install
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Plug and Play
• Set of hardware and software standards
developed by Intel, Microsoft, and others
• Creating devices that are able to configure
themselves when installed
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Bus Lines
• Connect parts of the CPU to each other
• Data roadway for traveling bits
– Measured as bus width
– More lanes, faster traffic
• Two basic categories
– System buses
– Expansion buses
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Expansion Buses
• Connects the CPU to other components on
the system board, including expansion slots
• Principal types
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Industry Standard Architecture (ISA)
Peripheral Component Interconnect (PCI)
Accelerated Graphics Port (AGP)
Universal serial bus (USB)
FireWire buses (HPSB)
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Ports
• Socket for connecting external
devices
• Ports can connect directly to
the system board or they can
connect to cards that are
inserted into slots on the
system board
• Two Types
– Standard Ports
– Specialized Ports
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Ports
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Cables
• Used to connect exterior devices to the
system unit via the ports
• One end of the cable is attached to the
device and the other end has a connector
that is attached to a matching connector on
the port
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Power Supply
• Computers require direct current (DC)
• DC power provided by converting alternating
current (AC) from wall outlets or batteries
• Desktop computers use power supply units
• Notebooks and handhelds use AC adapters
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A Look to the Future
Xybernaut Corporation
• Wearable computers
• Send and receive
email
• Maintain your
personal schedule
book
• Play interactive
games and surf the
Web from anywhere
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Discussion Questions
• Describe the four basic types of system units.
• Describe the two basic components of the
CPU.
• What are the differences and similarities
between the three types of memory?
• Identify five expansion cards and describe
the function of each.
• Identify and describe four standard ports and
two specialized ports.
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End of Chapter 6
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