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Teachers Discovering Computers
Integrating Technology in a Changing World
8th Edition
Chapter Four
Hardware for Educators
Chapter Objectives
• Describe the system unit
• Define the term bit and describe how a series of
bits are used to represent data
• Identify the major components of the system unit
and explain their functions
• Explain how the CPU uses the four steps of a
machine cycle to process data
• Describe the four types of input as well as input
devices and pointing devices
• List the characteristics of a keyboard and identify
various types of keyboards
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Chapter Objectives
• Differentiate among the four types of output
• Identify different types of output devices
• Explain differences among various types of
printers
• Differentiate between storage and memory
• Identify types of storage media and devices
• Differentiate between CDs, DVDs, and BDs
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The System Unit
• System unit
– Boxlike case that houses
the electronic components
a computer uses to process
data
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Data Representation
• Analog vs. Digital
• Digital
– Two states
• (1) on
• (0) off
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Data Representation
• Binary number system
• Combination of ones and zeroes represent
characters
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Data Representation
• ASCII
– American Standard Code for Information Interchange
– Converting a keyboard stroke into a byte
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The Components of the System Unit
• The Motherboard
– Contains many of the electronic components
– Chip
• A small piece of semiconducting material usually no bigger
than one-half-inch square and is made up of many layers of
circuits and microscopic components that carry electronic
signals
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The Components of the System Unit
• CPU
– Interprets and carries out the basic instructions that
operate a computer
– Microprocessor manages most of a computer’s
operations
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The Components of the System Unit
• The Control Unit
– A component of the CPU that directs and coordinates most of the
operations in the computer
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Fetch - get the next instruction from memory
Decode - translate the instruction
Execute - carry out the command
Store the result - write the result to memory
Machine cycle
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The Components of the System Unit
• The Arithmetic/Logic Unit
– Performs the execution part of the machine cycle
– Arithmetic (addition, subtraction, multiplication,
division)
– Comparison (greater than, equal to, less than)
– Logical (AND, OR, NOT)
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The Components of the System Unit
• The System Clock
– Synchronizes all computer operations
– Each tick is called a clock cycle
– Faster clock means more instructions the CPU can
execute each second
– Speed measured in gigahertz (GHz)
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The Components of the System Unit
• Memory
– Used to store data and instructions
• The operating system and other system software
• Application software
• Data being processed by application programs
– Bytes are stored at specific locations or addresses
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The Components of the System Unit
• Memory
– Size of memory is measured by the number of bytes
available
– Volatile memory – contents are lost when the
computer is turned off
– Nonvolatile memory – contents are not lost when the
computer is turned off
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The Components of the System Unit
• Random Access Memory (RAM)
– The memory chips in the system unit
– When the computer starts, certain operating system
files are loaded from a storage device into RAM
– Synchronous Dynamic RAM (SDRAM)
– Dual Inline Memory Module (DIMM)
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The Components of the System Unit
• Random Access Memory
(RAM)
– RAM Chips
• Smaller in size than
processor chips
• Commonly hold up to 4
gigabytes of memory
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The Components of the System Unit
• Random Access Memory (RAM)
– Configuring RAM
• The more RAM, the more programs and files a computer can
work on at once
• Software usually tells you how much RAM is required
• For an application to perform optimally, you usually need
more than the minimum specifications
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The Components of the System Unit
• Read-Only Memory
(ROM)
– Cannot be modified
– Contents not lost when
the computer is turned
off
• Flash Memory
– Type of nonvolatile
memory that can be
erased electronically and
rewritten on
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The Components of the System Unit
• Expansion Slots and Expansion Cards
– Expansion slot
• A socket on the motherboard that can hold an expansion card
• Add new devices or capabilities to the computer
– Expansion card
• Circuit board that enhances functions of a system component
and/or provides connections to peripherals
– Plug and Play
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The Components of the System Unit
• Removable Memory
Devices
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Flash memory cards
USB flash drives
PC Cards
ExpressCard modules
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The Components of the System Unit
• Ports and Connectors
– Port
• Point of attachment to the system unit
• Usually on the back and front of the system unit
– Connectors
• Used to plug into ports
– Male connectors
– Female connectors
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The Components of the System Unit
• Ports and Connectors
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USB
USB 2.0
USB 3.0
FireWire
Bluetooth
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What is Input?
• Any data or instructions you enter into
the memory of a computer
– Data – unprocessed items
– Programs - series of instructions that tells the computer
how to perform a task
– Commands - an instruction given to a computer program
– User responses - responses to questions or messages
from the software
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What are Input Devices?
• Any hardware component that allows you to enter
data, programs, commands, and user responses
into a computer
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What are Input Devices?
• The Keyboard
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Typing area
Numeric keypad
Toggle keys
Status lights
Arrow keys - arrow control keys
Function keys
Specialized buttons
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What are Input Devices?
• Pointing Devices
– An input device that allows you to control a pointer on
the screen
• Block arrow
• I-beam
• Pointing hand
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What are Input Devices?
• Pointing Devices
– Mouse
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One or two button mouse
Scroll wheel
Moving the mouse pointer
Clicking
Dragging
Double-clicking
Optical mouse
Wireless mouse
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What are Input Devices?
• Touchpad and Pointing Stick
– Touchpad – small, flat,
rectangular pointing device
that is sensitive to pressure
and motion
– Pointing Stick – pressuresensitive pointing device
shaped like a pencil eraser
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What are Input Devices?
• Pointing Devices
– Trackball
• Like a mouse, but the ball
mechanism is on top
• Requires frequent
cleaning
• Good when you have
limited desk space
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What are Input Devices?
• Pointing Devices
– Joystick
• Uses the movement of a vertical lever
• Often used with games
– Wheel
• Steering-wheel type input device
• Used to simulate driving a car or other vehicle
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What are Input Devices?
• Pointing Devices
– Touch and multi-touch
screens
• Monitor has a touch
sensitive panel
• Used to issue simple
commands or choose from
a list of options
• Some models of desktop
and notebook computers,
all tablet computers, and
many mobile devices have
touch screens
• Kiosks
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What are Input Devices?
• Optical Scanners
– Captures an entire page of text or images such as
photographs or artwork electronically
– Converts the text or image on the original document
into digital data that can be stored on a storage
medium and processed by the computer
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What are Input Devices?
• Pen Input
– Users write, draw, and
tap on a flat surface to
enter input
– Stylus – small metal or
plastic device that
looks like a tiny ink pen
but uses pressure
instead of ink
– Digital pen – slightly
larger than a stylus and
provides more
functionality
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What are Input Devices?
• Digital Cameras
– Allows you to take pictures and store the photographed images
digitally
– Download, or transfer, pictures to your computer
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What are Input Devices?
• Audio and Video Input
– Audio input
• Entering speech, music, or sound effects
• Sound card
• Speech Recognition
– Computer’s capability of distinguishing spoken words
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What are Input Devices?
• Audio and Video Input
– Video input
• Capturing a full-motion recording onto a computer and
storing the video on a computer’s storage medium
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What are Input Devices?
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What is Output?
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Text
Graphics
Audio
Video
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What are Output Devices?
• Any computer component capable of conveying
information to the user
• Commonly used output devices
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Display devices
Printers
Data projectors
Facsimile machines
Multifunction devices
Interactive whiteboards
Speakers, headphones, and earphones
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What are Output Devices?
• Display Devices
– Screen housed in a plastic or metal case
– Variety of sizes
– Cathode ray tube (CRT)
– Pixels
– Flat-panel displays
• LCD (liquid crystal display) monitors
• LCD screens
• Plasma monitors
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What are Output Devices?
• Plasma Monitors
– Some can measure more than
150 inches wide
– Uses gas plasma technology,
which sandwiches a layer of gas
between two glass plates
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What are Output Devices?
• Monitor Quality
– Resolution (sharpness and clarity)
• Expressed as number of columns and rows
– 1600 x 1200
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What are Output Devices?
• Televisions
– iPad users can stream their
music, photos, and videos
wirelessly to a display device
using AppleTV and AirPlay
– With game consoles, such as
Microsoft’s Xbox 360,
Nintendo’s Wii, and Sony’s
PlayStation 3, the output
device often is a television
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What are Output Devices?
• Printers
– An output device that produces text and graphics on a
physical medium such as paper or transparency film
– Hard copy (printout)
– Portrait orientation vs. landscape orientation
– Printing requirements vary
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What are Output Devices?
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What are Output Devices?
• Nonimpact Printers
– Do not strike paper
– Much quieter
– Ink-jet printers
• Spray tiny drops of ink
onto the paper
• Both black-and-white and
color
– Photo printers
• Produce photo lab quality
pictures
• Many use ink-jet
technology
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What are Output Devices?
• Nonimpact Printers
– Laser printers
• High-speed, high-quality
nonimpact printer
• Very high quality
resolution
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What are Output Devices?
• Data Projectors
– Allows an audience to view output
– LCD projectors
– Digital light processing (DLP) projector
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What are Output Devices?
• Facsimile (Fax) Machine
– Used to transmit and
receive an image of a
document over a telephone
line
– Stand-alone
– Fax modem
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What are Output Devices?
• Multifunction Devices
– Can print, scan, copy and
fax
– Less space
– Lower cost than separate
units
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What are Output Devices?
• Interactive whiteboards
– Touch-sensitive device,
resembling a dry-erase board
– A presenter controls the
computer program used to
display the image by:
• Clicking a remote control
• Touching the whiteboard
• Drawing on or erasing the
whiteboard
• Writing on a special tablet
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What are Output Devices?
• Speakers, Headphones, and
Earphones
– Voice output
– Audio output device
– Internal speaker
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What is Storage?
• The media on which data,
instructions, and information
are kept
• The devices that record and
retrieve data, instructions, and
information
• Similar to a filing cabinet
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Storage Media and Devices
• Storage medium
– Also called secondary storage
– Physical material
• Storage device
– Mechanism used to record and retrieve these items to
and from a storage medium
– Capacity measured in megabytes or gigabytes
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Storage Media and Devices
• Magnetic Disk
– Uses magnetic patterns to
store data, instructions, and
information on the disk’s
surface
– Formatting is the process of
preparing a disk for reading
and writing by organizing the
disk into storage locations
called tracks and sectors
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Storage Media and Devices
• Hard Disks
– Provide large storage
capacity
– Sizes range from 320 GB to
1.5 TB
– Consists of several
inflexible, circular disks,
called platters
– Magnetic storage device
– Formatting
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Storage Media and Devices
• Miniature and Portable Hard Disks
– Miniature hard disks are found in consumer
electronics and have greater storage capacities than
flash memory
– External hard disks connect to a
USB or FireWire port by a cable
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Storage Media and Devices
• Solid State Drives
– A storage device that typically uses flash memory to
store data, instructions, and information and contains
no moving parts
– Range in size
– Used in all types of computers
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Storage Media and Devices
• Optical discs
– Type of storage medium that consists of a flat, round,
portable disc made of metal, plastic, and lacquer that
is written to and read from using a laser
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Storage Media and Devices
• CDs and DVDs
– Optical storage media
– Used to distribute software
– Laser reads pits on the surface
– Used on multimedia computers
– Several types
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Storage Media and Devices
• Care of Optical Discs
– Can last up to 100 years if properly cared for
– Never bend a disc
– Avoid extreme temperatures and humidity
– Keep away from contaminants
– Do not stack or touch discs
– Use a protective case (jewel box or disc storage case)
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Storage Media and Devices
• CD-ROM
– Compact disc read-only
memory
– Can contain text, graphics,
video, as well as sound
– Can hold up to 1 GB
– Used to distribute software
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Storage Media and Devices
• CD-R and CD-RW
– Compact disc-recordable
• Can write on each part of the disc only one time
• Cannot be erased
– Compact disc-rewriteable
• Can write on multiple times
• Erasable disc
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Storage Media and Devices
• DVD and BD
– Digital video disc read-only memory (DVD-ROM)
• Can store from 4.7 GB to 17 GB
• High quality
• DVD-ROM drives
– BD (Blu-ray Disc) has storage capacities of 100GB, with
expectations of exceeding 200 GB
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Storage Media and Devices
• Miniature Mobile Storage Media
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Storage Media and Devices
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Storage Media and Devices
• USB Flash Drive
– Storage device that plugs into a USB port on a computer or
mobile device
• Smart Card
– Similar in size to a credit card
– Stores data on a thin microprocessor embedded in the
card
• Cloud Storage
– Rapidly growing Internet service that provides storage to
computer users
– Apple’s iCloud
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Storage Media and Devices
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Chapter Summary
• Describe the system unit
• Define the term bit and describe how a series of bits
are used to represent data
• Identify the major components of the system unit
and explain their functions
• Explain how the CPU uses the four steps of a machine
cycle to process data
• Describe the four types of input as well as input
devices and pointing devices
• List the characteristics of a keyboard and identify
various types of keyboards
78
Chapter Summary
• Differentiate among the four types of output
• Identify different types of output devices
• Explain differences among various types of
printers
• Differentiate between storage and memory
• Identify types of storage media and devices
• Differentiate between CDs, DVDs, and BDs
79
Teachers Discovering Computers
Integrating Technology in a Changing World
Chapter Four Complete
Hardware for Educators