Transcript Document

6
THE SYSTEM
UNIT
6-2
Competencies
Describe the four basic types of system units
Discuss how a computer uses binary codes
Describe the major system unit components
Describe system boards, microprocessors, and
memory
Describe the function of the system clock,
expansion slots, boards, and bus lines
Discuss ports, cables, and power supply
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6-3
System Units
Microcomputers
Desktop
Notebook
Tablet PC
Handheld
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6-4
Electronic Data and Instructions
Data and instructions are represented
electronically
Computers recognize digital signals
Binary system
Bit
Byte
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6-5
Binary Coding Scheme
Two state system
Off/on electrical states
Characters represented by 0s and 1s
Three types of schemes
ASCII - American Standard Code for Information
Exchange
EBCDIC - Extended Binary Coded Decimal
Interchange Code
Unicode
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6-6
Binary Code
Code
Uses
ASCII
Microcomputers
EBCDIC
Large Computers
Unicode
International Languages
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6-7
System Board
Connects all components
Allows communication between devices
Main board or motherboard
Circuit board
electronic components
Sockets
Slots
Bus lines
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6-8
Microprocessor
Central Processing Unit (CPU )
Two basic components
Control unit
Arithmetic and logic unit
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6-9
Microprocessor Chips
Chip capacities are expressed in word sizes
Types of microprocessor chips
CISC chips: Complex instruction chips
Most widely used design
Used by Intel
RISC chips: Reduced instruction set computer chips
Uses fewer instructions
Design is simpler and less costly
Used by the PowerPC
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6-10
Specialty Processors
Graphics coprocessors
Parallel processors
Smart cards
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6-11
Memory
Holding area for data, instructions, and
information
Types of memory chips
RAM – holds programs and data
ROM – fixed start-up instructions
CMOS – flexible start-up instructions
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6-12
Memory Capacity
Unit
Capacity
Megabyte (MB)
1 billion bytes
Gigabyte (GB)
1 million bytes
Terabyte (TB)
1 trillion bytes
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6-13
System Clock
Important measurement indicating speed
Located on a small chip
Produces electrical beats
Synchronizes operations
Expressed in gigahertz
Faster clock speed, faster computer
What is a gigahertz?
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6-14
Expansion Slots and Cards
Allow for new devices to be added
Open architecture
Slots provide for expansion
Expansion cards are also called …
Plug-in boards
Controller cards
Adapter cards
Interface cards
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6-15
Commonly Used Expansion Cards
Video cards
Modem cards
Network interface cards (NIC)
TV tuner cards
PC cards
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6-16
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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6-17
Types of Expansion Buses
Industry Standard Architecture (ISA)
Peripheral Component Interconnect (PCI)
Advanced Graphic Port (AGP)
Universal serial bus (USB)
FireWire buses
HPSB – high performance serial bus
Used with digital
camcorders & video editing software
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6-18
Ports
Socket for connecting external devices
Four common ports
Serial
Parallel
USB
FireWire
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6-19
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
Power Supply
Unit
AC adapter
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6-20
A Look to the Future
Xybernaut Corporation
Wearable computers
Called POMA
Includes…
Windows CE
Wireless pointing
device
Head-mounted display
MP3 player
Abridged Windows
Office programs
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6-21
Key Terms
AC adapter (164)
accelerated graphics port
(AGP) (163)
adapter card (159)
alternating current (AC)
(164)
analog (151)
arithmetic operation
(155)
Arithmetic logic unit (AL
ASII (152)
binary coding scheme
(152)
binary system (151)
bit (151)
bus (162)
bus line (154)
bus width (162)
byte (151)
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6-22
Key Terms
video card (159)
video capture card (159)
video recorder card (159)
volatile storage (157)
virtual memory (157)
word (155)
workstation (155)
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6-23
FAQs
What are the four basic types of system units?
What is analog? What is digital?
What is a microprocessor and what does it do?
What is RAM? What is ROM?
I hear a lot about flash memory. What is it?
I need a USB port to install a wireless mouse.
What are ports?
What is a network card?
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6-24
Discussion Questions
Explain how a computer understands
instructions.
Define memory and describe three types of
memory chips.
Explain the purpose of expansion cards and
slots. Give examples of some commonly used
expansion cards.
Describe how bus lines work.
© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved.