Professor Michael J. Losacco CIS 1110 Using Computers System
Unit Chapter 4
Slide 2
Chapter4 2/28 Overview Describe System Unit Components Identify
Motherboard Components Describe Processor Functions Explain
Computer Data Representation Differentiate Memory Types
Differentiate Ports & Connectors
Slide 3
Chapter4 3/28 System Unit Case Containing Electronic
Components
Slide 4
Chapter4 4/28 Common Components Processor Memory Adapter Cards
Video Sound Modem Network Ports Drive Bays Power Supply
Slide 5
Chapter4 5/28 Motherboard Main Circuit Board in System Unit
Contains Processor Memory Adapter Cards Chips Integrated
Circuits
Slide 6
Chapter4 6/28 Processor Central Processing Unit (CPU)
Interprets & Executes Basic Instructions Components Control
Unit Directs & Coordinates Operations Arithmetic Logic Unit
(ALU) Arithmetic (+-*/) Comparison (=) Logical (and or not)
Slide 7
Chapter4 7/28 Processor System Clock Controls Timing of All
Operations Generates Ticks Regular Electronic Pulses Smallest Unit
of Time Recognized by a Device
Slide 8
Chapter4 8/28 Processor System Clock Processor Speed Measured
by Ticks/Second MHz One Million Ticks/Second Type 100 Words/Minute
= 8 Characters/Second 8088 Processor @ 4.77 MHz Character 50,000
Other Tasks Character GHz One Billion Ticks per Second
Slide 9
Chapter4 9/28 Processor Machine Cycle Fetch Obtain Instruction
From Memory Decode Translate Instruction to Commands Execute Carry
Out Command Store Write Result to Memory CPU Executes 1-3+ Cycles
per Tick
Slide 10
Chapter4 10/28 Processor Machine Cycle Example 1) Fetch
instruction: Get number at address 123456 2) Decode instruction 3)
Execute: ALU finds the number (which is 5) 4) Store: The number 5
is stored in a register 5 8) Repeat steps for another number (which
is 6) 9) Fetch instruction: Add number in Reg1 to Reg2 10) Decode
instruction 11) Execute: ALU adds the numbers 12) Store: The answer
is stored in a register 13) Fetch instruction: Display answer on
screen 14) Decode instruction 15) Execute: Display answer on
screen
Slide 11
Chapter4 11/28 Processor Cooling Systems Heat Sink Component
that Cools Processor Heat Pipe Used in Notebooks Liquid Cooling
Continuous Fluid Flow Transfers Heat Away
Slide 12
Chapter4 12/28 Data Representation Binary Most Computers are
Digital Recognize Two Discrete States On / Off Equivalent Numbering
System Bits (Binary Digit) Two Unique Digits 0 / 1
Slide 13
Chapter4 13/28 Data Representation Byte Eight Bits Grouped
Together Represent Numbers Uppercase & Lowercase Letters
Punctuation Special Characters 35D35D
Slide 14
Chapter4 14/28 Data Representation Coding Systems ASCII PC
EBCDIC Mainframe Unicode Other Languages
Slide 15
Chapter4 15/28 Memory One or More Chips on Motherboard Each
Byte Stored in Unique Location Address Stores Three Basic
Categories of Items OS & Other System Software Application
Program Instructions Data Being Processed & Resulting Info
Slide 16
Chapter4 16/28 Memory Sizes
Slide 17
Chapter4 17/28 Memory RAM (Random Access Memory) Read From /
Written To by Processor Volatile Content Lost When Power is Absent
More = Faster Operation DRAM (Dynamic) Standard SRAM (Static) MRAM
(Magnetoresistive)
Slide 18
Chapter4 18/28 Memory Location Memory Resides on Small Circuit
Board Memory Module Memory Slots Hold Memory Modules On
Motherboard
Slide 19
Chapter4 19/28 Memory System Requirements Based on Types of
Applications Used Cache Speeds Computer Processes Stores Frequently
Used Instructions & Data
Slide 20
Chapter4 20/28 Memory ROM (Read Only Memory) Stores Permanent
Data & Instructions Non-volatile Types Firmware Permanently
Written Data BIOS (Basic Input / Output System) Sequence of
Instructions to Start Computer PROM Blank EEPROM Electrically
Erasable PROM
Slide 21
Chapter4 21/28 Memory Flash Non-volatile Can be Erased &
Reprogrammed Used in Cell Phone Digital Camera MP3 Player USB
Storage
Slide 22
Chapter4 22/28 Additional Functionality Expansion Slots &
Adapter Cards Expansion Slot Socket on Motherboard Holds Adapter
Card Adapter Card Enhances System Unit Provides Connections to
Peripherals Plug n Play Automatically Configured When
Installed
Slide 23
Chapter4 23/28 Additional Functionality Port Connects
Peripheral to System Unit Connector Joins Cable to Peripheral Male
or Female
Chapter4 25/28 Additional Functionality USB (Universal Serial
Bus) Printer, Digital Camera, Phone, Flash, etc. Bluetooth Wireless
Firewire Data Transfer IrDA Wireless Data Transfer
Slide 26
Chapter4 26/28 Bus Pathway Used to Communicate On Motherboard
Allows Devices to Communicate with Each Other Data Bus Address Bus
Bus Width Word Number of Bits Processor can Use at Once
Slide 27
Chapter4 27/28 Other Components Bay Opening Inside System Unit
Used to Install Additional Equipment Typically Holds Disk Drives
Power Supply Converts AC Power into DC Power Fan Keeps System Unit
Components Cool
Slide 28
Chapter4 28/28 Maintenance Clean Device Once or Twice a Year
Turn Off & Unplug Device Compressed Air to Blow Out Dust Clean
Case Exterior Antistatic Wipe Clean Monitor Cleaning Solution &
Soft Cloth