Transcript Book Title - California State University, Dominguez Hills

Computers in a
Changing
Society
By John Preston, Robert Ferrett,
and Sally Preston
© 2005 Prentice-Hall, Inc.
1
Computers in a
Changing Society
Chapter 3
Understanding Hardware
and Its Function
© 2005 Prentice-Hall, Inc.
2
Computers in a Changing Society
Chapter 3
Learning Objectives
I.
Categories of Computers
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II.
Identify characteristics of personal computers
(desktop, laptop or notebook, and Personal Digital Assistant)
Identify computer categories by capacity and function
Identify super computer characteristics and uses
Develop understanding of distributed processing and distributed databases
Working with Numbers, Text, Pictures, and Sound
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Develop understanding of numbering systems
Develop familiarity with pictures and associated characteristics
Gain an understanding of analog and digital transmission methods
© 2005 Prentice-Hall, Inc.
3
Computers in a Changing Society
Chapter 3
Learning Objectives
III.
Hardware and Basic Computer Functions
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IV.
Identify power control symbols with associated meanings
Identify input and output devices, characteristics, and functionality
Develop an understanding of memory, storage, and processing types and
characteristics
Develop an understanding of monitors and projectors
Examine types of printers, printer technology, and ink delivery
Examine casing indicator light functionality
Examine speaker functions
Connecting Parts of a Desktop
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Develop understanding of ports and plugs
Identify characteristics of surge protectors
Identify characteristics of uninterruptible power supplies (UPS)
© 2005 Prentice-Hall, Inc.
4
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Personal Computers
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Characteristics
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Also known as microcomputers
Similar to large computers
Intended for use by one person
Include input, processing,
storage, and output
Types
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Desktop
Laptop and Notebook
Personal Digital Assistant, Appliances, and Mobile Communication
© 2005 Prentice-Hall, Inc.
5
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Personal Computers
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Desktop
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Personal Computer, large in size
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Intended for use by one person
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Laptop and Notebook
Referred to as laptop computers or notebooks
Portable personal computer with battery
LCD (liquid crystal display) screen
Mouse, touch pad track ball, or pointing stick
Tablet PC
© 2005 Prentice-Hall, Inc.
6
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Personal Computers
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Personal Digital Assistant (PDA),
Appliances, and Mobile Communication
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PDA
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Hand-held or pocket size
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Used for managing daily tasks
(appointments, tasks, contact information, and e-mail)
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Palm Pilot popularized PDA
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Appliances
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Computers dedicated to a single task
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Task Examples: Internet connection, word processing, TV shows, playing games
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Mobile Communication Devices
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PDA and cell phone technology manufacturers
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Examples: E-mail, Web browsing, instant messaging, contact management software
© 2005 Prentice-Hall, Inc.
7
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Computers for Organizations
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Characteristics
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Used for communication and storage of mission critical information
Used for conducting Web-based business via Internet
Similar to personal computers, but high-powered
Intended for use by many people
Include input, processing, storage, and output
Physical environmental issues
Types
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Workstations
Network Servers
Midi, Midrange, and Mainframe File Servers
Supercomputers
© 2005 Prentice-Hall, Inc.
8
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Computers for Organizations
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Workstations
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Similar to home computer
Connected to local area network (LAN)
High-performance desktop computers
Physical environmental factors (wiring and temperature control)
Wireless connections using radio signals
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Security challenges such as eavesdropping
Network Servers
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Used for sharing information and resources via LAN
Coordinates computer and printer traffic and LAN communication
Provides Web page and e-mail functions on Internet or company intranet
Size of file cabinets stored in telecommunications closets
Physical security and associated value
© 2005 Prentice-Hall, Inc.
9
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Computers for Organizations
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Midi, Midrange, and Mainframe File Servers
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Computer names describe capability level
Storage of mission critical data within databases
Vary in capability depending on size of organization and files
User communication with file servers often facilitated by:
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Dumb terminals
Point of Sale (POS) terminal
Midrange—Used in mid-sized companies with thousands of customers
Mainframe—Used in large companies with millions of customers
Physical Environment
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Dedicated space with climate control
Wiring incorporating plenum flooring (elevated)
Security measures
Emergency backup and disaster recovery plan
© 2005 Prentice-Hall, Inc.
10
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Computers for Organizations
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Supercomputers
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Ability to quickly evaluate complex interactions
Example: Modeling using finite element analysis (airplane design)
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finite elements—small pieces of airplane design detail
formulas—determine reaction to air flow and stress
Enormous processing capability
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simulations
Most expensive of all computers
Locations
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National research laboratories
Large research universities
Government facilities
Military research facilities
© 2005 Prentice-Hall, Inc.
11
Computers in a Changing Society
Chapter 3
I.
Categories of Computers
Distributed Processing and Distributed Databases
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Provide alternatives to large, expensive,
centralized computing
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Distributed Processing
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Process of breaking large computer
problems into manageable tasks
May be computers connected to the Internet
Example: Search for Extraterrestrial
Intelligence (SETI) Project
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Distributed Database
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Storage of large database on several smaller computers
Internet may be used to manage distributed databases
Sharing files using centralized storage location
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Server or Peer-to-Peer
Example: digital audio or video recordings
© 2005 Prentice-Hall, Inc.
12
Computers in a Changing Society
Chapter 3
II.
Working With Numbers, Text, and Pictures
Numbers and Text
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Decimal Numbering System
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Ten digits (0–9)
Binary Numbering System
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Two digits (0s and 1s)
Represent on and off
Used for mechanical devices
Binary number called binary digit or bit
Transistors
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Electronic switches
Replaced electrical devices
Use binary numbering system
© 2005 Prentice-Hall, Inc.
13
Computers in a Changing Society
Chapter 3
II.
Working With Numbers, Text, and Pictures
Numbers and Text
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Digital Computers
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Use binary digits to interact with users
Coding schemes
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American Standard Code for Information Interchange (ASCII)
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Standard for computer communication
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Uses binary assignments for letters in alphabet
(upper and lower-case), 10 decimal digits,
and special function keys
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Early ASCII—7 binary numbers/128 characters
Extended Binary Coded Decimal Interchange Code (EBCDIC)
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Expanded ASCII—8 digit binary numbers/256 characters
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Still in use today—IBM S/390 Mainframe
Unicode
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Newer code using 32 digit binary numbers
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Includes codes for characters in many languages
© 2005 Prentice-Hall, Inc.
14
Computers in a Changing Society
Chapter 3
II.
Working With Numbers, Text, and Pictures
Numbers and Text
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Digital Computers
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Bits and Bytes
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Bit—Each digit in a binary number
Bit is smallest unit of information computer can work with
Byte—8 digit binary number
Data transmission rates often given in bits per second (bps)
Additional Resource
http://www.howstuffworks.com
© 2005 Prentice-Hall, Inc.
15
Computers in a Changing Society
Chapter 3
II.
Working With Numbers, Text, and Pictures
Pictures
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Forms of Output
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Paper
Computer Screen
Pixels
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Binary numbers to letters using patterns of dots
On—Bright vs. Off—Dark
Greater resolution with more pixels
1024 x 768 (higher resolution) vs. 800 x 600 (less resolution)
Three elements to produce color
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red, green, blue
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
II.
Working With Numbers, Text, and Pictures
Sounds
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Sounds Waves
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Dynamic—volume and pitch
Signal Transmission
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Analog
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Digital
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Used prior to digital computers
Varied in fashion analogous to volume and pitch
Conversion process uses specialized equipment—A to D converter (analog to digital)
Faster than analog
Smoothes out signals—static-free
Conversion Process uses specialized equipment—D to A converter (digital to analog)
Digital Computers
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Manipulate numbers and communicate via mechanical devices, sound, and images.
Unable to interpret user senses (touch, smell, taste)
© 2005 Prentice-Hall, Inc.
17
Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Hardware—Physical components of computer
Software—Instructions that direct computer activity
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Power Control Buttons
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Symbols indicate what the button can do
Symbol on left is 0 or 1—Turns power off or on
Next Symbol—1 overlapping 0
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Standby or Sleep Mode—Partially powered state
Input Devices
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Keyboard
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Most commonly used piece of input hardware
Programmable function keys
Laptop users
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions

Input Devices
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Keyboard
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions

Input Devices
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Keyboard
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Special Function Keys
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Function Keys (Fn)
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Numeric Key Pad
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Numlock
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Combination Keys
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Control (Ctrl)
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Alternate (Alt)
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Shift
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Ctrl-Alt-Delete
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Special Characters (plus + sign)
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Keyboard Recognition
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Apple Computer Users
© 2005 Prentice-Hall, Inc.
20
Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions

Input Devices
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Mouse, Trackball, Touchpad, and Joystick
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Pointer control and variations
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Convert physical motion into motion of screen pointer
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Mouse
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Common input device
Positioning
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X axis (left-to-right position)
Y axis (up-and-down position)
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Mouse pad
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Components and motion conversion—A-D converter
Optical mouse—Use reflected light beams
Trackball
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Upside down mouse
Use fingers to move, not arm
© 2005 Prentice-Hall, Inc.
21
Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions

Input Devices
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Mouse, Trackball, Touchpad, and Joystick
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Joystick
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Uses same technology as mouse or trackball
Rotating ball is inside case with a rod attached for control
Game controllers
Pointing Stick
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Small knob in some laptop keyboards
Responds to sideways pressure
Touchpad
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Commonly found on laptops
Small rectangle of glass below spacebar
Interprets finger touch
Sensitive to touch
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Input Devices
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Scanners
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Convert input one row at a time
Used for pictures or printed documents
Friendly and affordable
Flatbed scanners
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Physical components and scanning process
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Pane of glass and fluorescent lamp
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A-D Conversion with pixel assignment
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Dots Per Inch (dpi)—Used for rating scanners
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Image storage requirements
Multi-Function Devices
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All-in-one machines
Print, fax, copy, scan
Optical Character Recognition (OCI) Programs
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Convert printed documents to text (ASCII or Unicode)
Software bundles
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Input Devices—Digital and Video Cameras
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Digital Cameras
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Input Process
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Lens focuses an image on an array of light-sensitive
detectors and converts image into electrical signals
A-D converter produces number representing
detected image brightness
Digital numbers recorded on flash memory removable storage
Image transfer options
Wires and docking station
Flash memory on compact, removable Flash cards
Video Cameras
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Like digital cameras, but can take several pictures per second
Frames per second—Number of pictures taken each second
Video conferencing or situation monitoring
Internet transmission and web cams
Hand-held digital video cameras
© 2005 Prentice-Hall, Inc.
24
Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Input Devices
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Microphones
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Sound conversion to analog signals
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A-D converter changes sound to binary numbers
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Voice recognition programs
Types of microphones
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Recordings
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E-mail attachments
Conference calls
Correct placement
© 2005 Prentice-Hall, Inc.
25
Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Processing
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Definition: Performing mathematical or logical operations on data
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Transistors
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Invented in 1950s
Replaced vacuum tubes and mechanical switches
Integrated Circuits (IC)
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Replaced individual transistors in mid 1970s
Also called chips
Contain millions of transistors
Perform specific or many tasks
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Processing
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Microprocessor
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Also known as Central Processing Unit (CPU)
Purpose: Accept instruction, retrieve data, perform data operations, output results
Early CPUs—Worked with 8 digit binary numbers (8-bit processor)
Modern CPUs—Work with 32 or 64 digit binary numbers
Clock—Special purpose IC for activity coordination
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Megahertz (millions of pulses per second) and gigahertz (billions of pulses per second)
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Clock Speed—Indicator of processor performance
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Applications require high-speed processors
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CPU communicates via data bus
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Pathways for transmission of binary digits
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32-bit data bus has 32 separate pathways
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Part of motherboard
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Connects integrated circuits to each other
and slots for connection of other devices
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Memory
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CPU processes data in form of memory
Optimum—Low cost, fast, reliable
Non-existent optimum
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Random Access Memory (RAM)
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Uses special purpose integrated circuit
Also called physical memory
Mounted on small circuit boards that plug into sockets on motherboard
RAM memory ICs require continuous power
Virtual memory
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Backup for low RAM
Slower than RAM
RAM measured in megabytes
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One byte approximately one character
Simultaneous applications
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Storage
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Low-cost methods
Slower than RAM
Measurements
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Kilobytes (1 thousand bytes)
Megabytes (1 million bytes)
Gigabytes (1 billion bytes)
Hard Disk
Portable Data Storage
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Disks and Drives
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Zip
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Floppy
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CD-ROM, CD-R, and CD-RW
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DVD
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USB
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Storage precautions
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Storage
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Hard Drive
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Stores data using magnetism
Hard disk
Stack of thin, rigid metal disks
Usually referred to as C: drive
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Disks—Devices that store information using magnetic methods
Discs—Devices that store information using optical methods
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Storage
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Portable Data Storage
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Floppy Disks
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Plastic disk with magnetic material
Data recorded as binary numbers
Generally referred to as Drive A:
(other than Macintosh) and/or B:
Hold 1.44 Megabytes
Keep away from magnets (stereo speakers)
Zip Disk
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Similar to floppy disks
Require proprietary drive
Less common than floppy disks
Hold 250 Megabytes
Being replaced by forms of compact disc (CD)
Keep away from magnets (stereo speakers)
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Storage
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Portable Data Storage
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CD-ROM, CD-R, and CD-RW discs
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Store information as binary numbers
Make small pits that absorb light
with laser beam and reflection
CD-ROM
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Read-Only Memory
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Oldest and most common
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CD-ROM drive only reads
CD-R
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Read many, write once
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Holds more than floppy
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Cost approximates floppy
CD-RW
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Re-writeable like floppy
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Holds more data than floppy
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Costs more than floppy or CD-R
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Storage
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Portable Data Storage
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Disc Writing—Two Patterns
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Continuous Spiral
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Data written in concentric circles
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Intended for use in continuous stream (music or video)
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File Allocation Table (FAT) —Data location
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FAT used by floppy and hard disks
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Digital Versatile Disc (DVD)
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Spiral tracks recorded on two different layers and on both sides of the disc
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Hold approx. 4.7 gigabytes or 4700 megabytes
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Holds about 133 minutes of 30 frames per second full screen video
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DVD disc drives—Data backup drives or writing DVDs
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Work on reflected light
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Hazards—Dirt, heat, scratching
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Cleaning and labeling procedure
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions

Storage
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Portable Data Storage
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USB—Universal Serial Bus
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Hardware interface for low-speed peripheral devices
Small rectangular hole in front of computer
Port for flash memory devices (key-chain size)
Devices can store data without power source
Disk-on-key USB drives or thumb drives
Convenient alternative to floppy or CD
Storage capability varies (64 MB–1 GB)
Emulates hard drive
Cost effective storage solution
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Output
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Monitors and Projectors
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Monitors
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CRT—Cathode Ray Tube
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Similar to television
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Used by monitor
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Consists of glass picture tube
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Shape—convex or flat screen
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Measured diagonally across face of tube
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Viewable area—smaller than size of tube
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LCD—Liquid Crystal Display
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Used in portable computers
Backlight—Florescent light (backlight) behind flat panel
Lighting process
Flat panel monitors
LCD Monitors—Measured diagonally, same viewable area
Cost compared to CRT
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Output
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Monitors and Projectors
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Projectors
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Used for group viewing when coupled with computer
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Monitors designed for large-scale image projection
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Lumens—Brightness of light from projector
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Common projectors—use three LCD screens (one for each color)
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Texas Instruments—Mirror technology alternative to LCD
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Accept inputs from VCR
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May project video or television signals
Printers
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Impact
Dot-Matrix
Laser Printer
Inkjet
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
III.
Hardware and Basic Computer Functions
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Output
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Indicator Lights
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Activity alerts—Located near front of case
Colors—Indicate unique activities
Speakers
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Use—Music, sound effects, games, speaking documents, alerts
Sub-woofer—Large speaker plays low-bass notes
External speakers
Small speaker—Inside case
Hardware alert—Beeps in technical code
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
IV.
Connecting Parts of a Desktop Computer
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Peripherals and Ports
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Peripherals—Devices connected to computer
Ports
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Location for connecting peripheral devices
Vary in size, but unique to particular peripheral
Key—Corresponding plastic projection in plug
USB Port
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Universal Serial Bus (USB)
Accepts variety of devices
(keyboard, mouse, printer, scanner,
video camera, speakers, docking
cradles, flash memory, etc.)
USB 2.0 and 1.1
Type A USB and Type B USB
Hubs—Multiple USB Connections
Hot-Swappable
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
IV.
Connecting Parts of a Desktop Computer
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Peripherals and Ports
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Serial Port
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Originally designed to work with telephone modems
Older connection—Labeled with zeros and ones
Like USB, data transmitted sequentially, but 100x slower
Connect mouse or keyboard, but being discontinued
Parallel-Printer Port
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8 wire pairs used for data transmission
Older connection—Faster than serial port
New printers—Use USB or parallel connector
PS/2 Port
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Round, serial connection with single direction key
Used for keyboards and mice
Confusion—keyboard and mouse port
Being replaced by USB, but adapter available
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
IV.
Connecting Parts of a Desktop Computer
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Peripherals and Ports
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Wireless Mouse or Keyboard

No wires—Use radio waves for transmission
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Require batteries
Receiver plugged into computer using PS/2 or USB plug
FireWire and SCSI

FireWire—Apple’s version of IEEE standard 1394 serial bus

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Advantages over USB

Higher data transfer rate than USB 1.1, but comparable to 2.0

Even higher data rates planned for future
SCSI – Small Computer System Interface

Scuzzy

Since 1986—older connection method for scanners, external hard drives, etc.

Several variations

Terminator—required at end of SCSI bus to prevent signal bounce
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
IV.
Connecting Parts of a Desktop Computer

Peripherals and Ports
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RJ-11
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
Registered Jack 11—Telephone connector with six wires
Jack—Refers to receptacle and plug
U.S. Federal Communications Commission (FCC)


Sets standards for telephone connection services
RJ-11 Jacks



Wall—The RJ-11 jack that connects modem to telephone service
Phone—The RJ-11 jack that connects to a normal phone plug
RJ-45




Similar to RJ-11 with 8 wires
Used for network connections
Network Interface Card (NIC)—Housing for RJ-45 jack
VGA Connector


Video Graphics Adapter (VGA) port
Same shape and size as serial port—causes confusion
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Computers in a Changing Society
Chapter 3
IV.
Connecting Parts of a Desktop Computer

Peripherals and Ports

Speaker and Microphone



Connect using 2.5-millimeter stereo plugs
Color coding or icon label identifies sockets
Power Cords




Detachable from computer, standardized,
interchangeable, plugs into wall
Three-prong male plug at one end and
three hole female plug at the other end
Common voltages—115 volt power in U.S. and 220 volt in Europe
Surge Protectors and Uninterruptible Power Supplies




Plug strip
Circuit breaker
Surge suppressors
Uninterruptible power supplies (UPS)
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Computers in a Changing Society
Chapter 3
Chapter Summary
 Outline
Objectives
(Achievement of objectives from the text portion of the chapter may be evaluated using T/F, matching,
completion, multiple choice, and other testing methods)
Personal Computers
Identify the difference between a desktop, laptop or notebook, and a Personal Digital Assistant: a desktop computer is designed for
individual use but isn't portable, laptop and notebook are synonyms for portable computers that have the same functions as a desktop,
and a PDA is dedicated to performing certain functions like managing calendar and contact lists.
Computers for
Organizations
Identify the difference between categories of computers by their relative capacity and by their function:
a) Super computers are the most powerful; they model systems using finite element analysis; b) Mainframes are larger than midrange but both are used to manage databases as well as provide Web server functions; c) They are often called file servers because
their main function is to look up database files; d) Servers or LAN servers provide coordination of other servers on a local area
network; e) Personal computers or workstations are used by one person at a time.
Supercomputers
Identify the types of problems that require a supercomputer: modeling complex systems in which the parts require interaction and
complex calculations.
Distributed Processing
and Databases
Identify the types of problems that are suitable for distributed processing: sections of the problem may be solved without interaction
with other parts of the problem.
Identify examples of distributed databases: a) Customer records; b) Music and video files.
Numbering Systems
Identify the relationship between characters and bytes: a byte of binary numbers represents each character.
Identify the role of ASCII and Unicode standards: ASCII standard uses 8-bit numbers for 256 possible characters; Unicode uses 32
bit binary numbers and has codes for characters in many different languages.
Pictures
Identify relationship between pixels and visible details: more pixels per screen means finer details may be seen.
Analog and
Digital
Match the types of information that changes smoothly with time and which representation method is most suitable: sounds, water
pressure, automobile speed, etc. : analog.
Identify the function of A-D and D-A converters and how they are used: A-D converters change analog signals to digital by
sampling and assigning numbers; D-A converters reverse the process.
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
Chapter Summary
Power Control
Symbols
Match power control symbols with their associated meanings: a) Single vertical line, a one, represents on; b) Single circle, a zero,
represents off; c) A vertical line inside a circle indicates a button that can turn the power on or completely off; d) A broken circle
with a vertical line indicates a button that can turn power on but only partially off, sometimes called a standby position.
Keyboards
Identify examples of function keys: Ctrl, Alt, Shift, Fn, (Apple-Command, Option)
Pointing Devices
Identify features and maintenance issues for mice and trackballs: lint can get wrapped around the rollers inside the device, which
must be removed periodically.
Scanners
Identify types of scanners and how they convert paper documents and pictures into digital files: Flatbed scanners shine a bright light
at the document one line at a time and convert the reflection into digital data. Some scanners are built into printers and the paper
moves past the lamp.
Digital Cameras
and Video
Identify how digital cameras connect to computers: a) USB connection may be used or a flash memory card may be removed from
the camera and placed in a device that is attached to the computer through a USB or serial port; b) Firewire or SCSI connections may
be used to transfer digital video files.
Microphones
Identify uses for microphones: recording voices, entering commands, dictating text
Identify appropriate placement for microphones when using voice recognition software and for conferencing: Voice recognition
programs require the microphone to be within an inch or so of the speaker's mouth.
Central Processing Unit
Identify measurements used to rate CPU performance: clock speed in megahertz and size of numbers in bits that may be processed
Memory and Storage
Identify the difference between memory and virtual memory: memory is RAM, which resides on integrated circuits, while virtual
memory uses space on a storage device like a hard disk.
Compare storage methods by speed and typical capacities: the hard disk is the largest and fastest with sizes from 20 gigabytes to over
100 gigabytes, DVDs store approximately 1.2 gigabytes, CDs store around 600 megabytes, Zip disks store up to 250 megabytes,
floppy disks store 1.44 megabytes.
Distinguish between disks and discs: magnetic media use disks and optical media use discs.
Identify the different types of optical storage methods: DVD had multiple layers and is two-sided, CD-ROM is read only, CD-R is
recordable, CD-RW is recordable and re-writable.
© 2005 Prentice-Hall, Inc.
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Computers in a Changing Society
Chapter 3
Chapter Summary
Monitors and
Projectors
Identify the difference between CRT and LCD monitors: CRTs use a large glass tube in which an electron beam starts at the small end and
strikes the phosphors at the wide end; LCDs use a backlight and small elements of liquid that are transparent or opaque depending on an
applied electric current.
Identify the different methods of measuring size of monitors: both are measured diagonally, but LCDs measure viewable screen space where
CRTs measure to the edge of the tube, which is hidden behind the edge of the case.
Identify the difference between flat screen and flat panel monitors: flat screen is a CRT with a flat front on the tube, flat panel is a thin
monitor.
Compare brightness of projectors: projectors with higher lumen ratings are brighter and may be used with larger screens in brighter rooms.
Printers
Identify types of printers and their ink delivery systems: impact uses devices that hit an inked ribbon to transfer ink to paper, laser printers use
toner like a copier, inkjets use a spray of ink droplets.
Indicator Lights
Identify the function of indicator lights on the case: show when a device is in use, such as a floppy disk drive or the hard disk
Speakers
Identify functions of speakers: music, audio cues, and trouble codes
Ports and Plugs
Identify types of USB plugs: Type A is rectangular, type B is smaller with two angled corner
Compare speeds of USB 1.1 and USB 2.0 connections: USB 2.0 is 40 times faster at 480 megabits per second
Identify common uses of Firewire connections: connection to digital video cameras
Distinguish between an RJ-11 and RJ-45 connector and their functions: RJ-11 is a typical telephone jack and RJ-45 is a typical ethernet jack
Identify the most likely problems when connecting the parts of a computer to the case: PS/2 plugs for keyboard and mouse can fit in the
wrong port, the VGA and serial ports are the same size and shape but have a different number of pins
Surge Protectors
and UPS
Identify the functions of a surge protector and how they differ from a circuit breaker: a surge protector protects from fluctuations in power
such as surges in voltage due to operating large motors on the same circuits or from pulses caused by lightning
Describe the function of an uninterruptible power supply: provide backup power for a short time to allow orderly shutdown
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