chapter 04: hardware for educators

Teachers Discovering Computers

Integrating Technology in a Changing World

8th Edition

Chapter Four

Hardware for Educators

http://www.scseries.com/


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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• 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 Control Unit– A component of the CPU that directs and coordinates most of the

operations in the computer

• 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 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 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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• 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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• 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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• 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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– RAM Chips

• Smaller in size than processor chips

• Commonly hold up to 4 gigabytes of memory

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– 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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• 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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• 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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• Removable Memory Devices– Flash memory cards

– USB flash drives

– PC Cards

– ExpressCard modules

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• 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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• Ports and Connectors

– 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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• The Keyboard– Typing area

– Numeric keypad

– Toggle keys

– Status lights

– Arrow keys - arrow control keys

– Function keys

– Specialized buttons

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• 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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– Mouse

• One or two button mouse

• Scroll wheel

• Moving the mouse pointer

• Clicking

• Dragging

• Double-clicking

• Optical mouse

• Wireless mouse

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• Touchpad and Pointing Stick

– Touchpad – small, flat, rectangular pointing device that is sensitive to pressure and motion

– Pointing Stick – pressure-sensitive pointing device shaped like a pencil eraser

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– 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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– 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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– 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

• Kiosks39




• 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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• 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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• Digital Cameras

– Allows you to take pictures and store the photographed images digitally

– Download, or transfer, pictures to your computer

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• 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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• 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 is Output?

• 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– Display devices

– Printers

– Data projectors

– Facsimile machines

– Multifunction devices

– Interactive whiteboards

– Speakers, headphones, and earphones

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• 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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• 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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• Monitor Quality

– Resolution (sharpness and clarity)

• Expressed as number of columns and rows– 1600 x 1200

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• 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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• 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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• 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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• Nonimpact Printers

– Laser printers

• High-speed, high-quality nonimpact printer

• Very high quality resolution

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• Data Projectors

– Allows an audience to view output

– LCD projectors

– Digital light processing (DLP) projector

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• 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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• Multifunction Devices

– Can print, scan, copy and fax

– Less space

– Lower cost than separate units

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• 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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• 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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• 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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• 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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• 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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• 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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• 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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• 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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• 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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• 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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• 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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• 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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• Miniature Mobile Storage Media

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• 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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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



chapter 04: hardware for educators

Education