1. 2 Te chnology in Action Chapter 2 Looking at Computers: Understanding the Parts

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TeTechnology in Actionchnology in Action

Chapter 2Chapter 2Looking at Computers: Looking at Computers:

Understanding the PartsUnderstanding the Parts

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Chapter TopicsChapter Topics

• Functions of a computerFunctions of a computer

• Data versus informationData versus information

• Bits and bytesBits and bytes

• Input devicesInput devices

• Output devicesOutput devices

• System unitSystem unit

• ErgonomicsErgonomics

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Computers Are Data Computers Are Data Processing DevicesProcessing Devices

• Computer’s four major functions:Computer’s four major functions:– Gathers data (users input data)Gathers data (users input data)– Processes data into informationProcesses data into information– Outputs data or informationOutputs data or information– Stores data and informationStores data and information

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Data vs. InformationData vs. Information

• Data: Representation of a fact or idea Data: Representation of a fact or idea

• Information: Organized, meaningful dataInformation: Organized, meaningful data

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Bits and Bytes: Bits and Bytes: The Language of ComputersThe Language of Computers

• Bit– Binary digit– 0 or 1

• Byte– Eight bits

• Each letter, number, and character = a string of eight 0s and 1s

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How Much Is a Byte?How Much Is a Byte?

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Computer SoftwareComputer Software

• Software: Programs that enable Software: Programs that enable hardware to perform different taskshardware to perform different tasks– Application softwareApplication software– System softwareSystem software

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Computer HardwareComputer Hardware

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Input DevicesInput Devices• Devices used to enter information or Devices used to enter information or

instructions into the computerinstructions into the computer– KeyboardKeyboard– Mouse/Mouse/

pointing devicepointing device– Microphone Microphone – ScannerScanner– Digital cameraDigital camera– StylusStylus

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KeyboardsKeyboards

• The QWERTY layout The QWERTY layout is standard on most is standard on most PCsPCs

• Enhanced keyboard Enhanced keyboard features include features include number, function, and number, function, and navigation keys.navigation keys.

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Dvorak KeyboardsDvorak Keyboards

• Puts the most commonly used keys on “home keys”Puts the most commonly used keys on “home keys”• Reduces distance of finger stretchesReduces distance of finger stretches

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Specialty KeyboardsSpecialty Keyboards• Notebook keyboardNotebook keyboard• PDA stylusPDA stylus• Tablet PCsTablet PCs• Wireless keyboardWireless keyboard

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MiceMice• Optical mouseOptical mouse

– Needs no mouse padNeeds no mouse pad– Doesn’t need cleaningDoesn’t need cleaning– Is more expensiveIs more expensive

• TrackballTrackball– Easier on wristsEasier on wrists– Stays stationary on deskStays stationary on desk

• Wireless Wireless – Use radio or light wavesUse radio or light waves

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New Mouse FeaturesNew Mouse Features• Instant viewerInstant viewer

• MagnifierMagnifier

• Customizable Customizable buttonsbuttons

• Web searchWeb search

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Other Input DevicesOther Input Devices• ScannersScanners

– TextText– Images Images

• Digital camerasDigital cameras– Images Images – Video Video

Flatbed scanner

Handheld scanner

Digital camera

Camcorder

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Other Input DevicesOther Input Devices• EPOS Digital PenEPOS Digital Pen

• Web CamWeb Cam– Live videoLive video

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Inputting SoundInputting Sound• Microphones Microphones

used for:used for:– PodcastsPodcasts– Video-Video-

conferencingconferencing– Internet phone Internet phone

callscalls– Speech Speech

recognition recognition

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Input Devices for the Input Devices for the Physically ChallengedPhysically Challenged

• Visual impairmentsVisual impairments– Voice recognitionVoice recognition– Keyboards with large keysKeyboards with large keys– On-screen keyboardsOn-screen keyboards

• Motor control issuesMotor control issues– Special trackballsSpecial trackballs– Head-mounted devicesHead-mounted devices

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Output DevicesOutput Devices

• Send processed data out of the computerSend processed data out of the computer– MonitorsMonitors– PrintersPrinters

• Output devices make:Output devices make:– Soft copies (video, sounds, control signals)Soft copies (video, sounds, control signals)– Hard copies (print)Hard copies (print)

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Monitor TypesMonitor Types• CRT CRT Cathode Ray TubeCathode Ray Tube

– Less expensiveLess expensive– Use much more spaceUse much more space– Use more energyUse more energy– Offer better viewing anglesOffer better viewing angles– Legacy technologyLegacy technology

• LCD LCD Liquid Crystal DisplayLiquid Crystal Display– More expensiveMore expensive– Use far less spaceUse far less space– More energy efficientMore energy efficient– Less viewable from an angleLess viewable from an angle

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Key Monitor FeaturesKey Monitor Features

• Screens are grids made up of millions of pixelsScreens are grids made up of millions of pixels ..

• LCDs: Liquid crystal is sandwiched between two LCDs: Liquid crystal is sandwiched between two transparent layers to form imagestransparent layers to form images

• CRTs: Pixels illuminated by electron beam that CRTs: Pixels illuminated by electron beam that passes back and forth across screenpasses back and forth across screen

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LCD Quality FactorsLCD Quality Factors

• ResolutionResolution

• Passive vs. active matrix displayPassive vs. active matrix display

• Viewing angleViewing angle

• Contrast ratioContrast ratio

• BrightnessBrightness

• Response timeResponse time

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LCD versus CRTLCD versus CRT

• LCD monitors: LCD monitors: – take up less spacetake up less space– are generally brighterare generally brighter– cause less eyestraincause less eyestrain– use less energyuse less energy– weigh less weigh less

• CRT monitors: CRT monitors: – used to offer more resolutionsused to offer more resolutions– used to produce better color and clarityused to produce better color and clarity

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Other Video OutputOther Video Output

• Touch-screen monitorsTouch-screen monitors– Double as both input and output devicesDouble as both input and output devices

• Data projectors Data projectors – Project a computer image to a large screen Project a computer image to a large screen

for sharing with large groupsfor sharing with large groups

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Printers Printers

• Impact printersImpact printers– Dot-matrixDot-matrix

• Nonimpact printersNonimpact printers– InkjetInkjet– Laser Laser

• Specialty printersSpecialty printers– MultifunctionMultifunction– PlottersPlotters– Thermal printersThermal printers

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Nonimpact PrintersNonimpact Printers

• InkjetInkjet– Less expensive deviceLess expensive device– Print high-quality color

images cost effectively • LaserLaser– More expensive deviceMore expensive device– Faster printing speedFaster printing speed– Less expensive per page Less expensive per page

in B&Win B&W– Color lasers are Color lasers are

becoming less expensivebecoming less expensive

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Choosing a PrinterChoosing a Printer

• Speed (ppm)Speed (ppm)

• Resolution (dpi)Resolution (dpi)

• Color outputColor output

• MemoryMemory

• Use and costUse and cost

• Cost of consumablesCost of consumables

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Outputting SoundOutputting Sound

• Speakers and headphonesSpeakers and headphones

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The System UnitThe System Unit

• Box that contains the central electronic components of the computer::– CPU/RAM/CPU/RAM/

motherboardmotherboard– Expansion cardsExpansion cards– Power supplyPower supply– Storage devicesStorage devices

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The Front PanelThe Front Panel

• Power controlPower control• Drive baysDrive bays• Memory card Memory card

readerreader• Productivity Productivity

portsports

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Power ControlsPower Controls

• Power-on button: Turns on system, should not be used to turn it off

• Other options: – Sleep modeSleep mode– HibernationHibernation– Warm bootWarm boot

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Drive BaysDrive Bays

• Internal drive bays:Internal drive bays:– Cannot be access from outside the systemCannot be access from outside the system– Reserved for internal hard drivesReserved for internal hard drives

• External drive bays:External drive bays:– Can be accessed from outside the systemCan be accessed from outside the system– CD or DVD drivesCD or DVD drives– Floppy and Zip drivesFloppy and Zip drives

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Hard Disk DriveHard Disk Drive

• Permanent (nonvolatile) storagePermanent (nonvolatile) storage

• Internal or external versionsInternal or external versions

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Flash Drives/Flash MemoryFlash Drives/Flash Memory

• Flash drives Flash drives (jump drives)(jump drives)– Newer storage Newer storage

alternativealternative– Plug into USB Plug into USB

portsports

• Flash memory Flash memory cardscards– Slide into slots in Slide into slots in

the systemthe system

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Storage Media CapabilitiesStorage Media Capabilities

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On the BackOn the Back

• Ports for peripheralsPorts for peripherals• Types of ports:Types of ports:

– Serial and parallelSerial and parallel– Audio and videoAudio and video– USBUSB– FireWireFireWire– ConnectivityConnectivity

• EthernetEthernet• ModemModem

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Inside the System UnitInside the System Unit

• Essential Essential electronic electronic components used components used to process datato process data

• Types of Types of components:components:– Power supplyPower supply– Hard disk driveHard disk drive– MotherboardMotherboard– CPUCPU– Expansion cardsExpansion cards

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The MotherboardThe Motherboard

• CPUCPU

• RAMRAM

• Expansion Expansion cards and cards and slotsslots

• Built-in Built-in componentscomponents

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Central Processing Unit (CPU)Central Processing Unit (CPU)• Referred to as the “brains” of the computerReferred to as the “brains” of the computer• Controls all functions of the computerControls all functions of the computer• Processes all commands and instructionsProcesses all commands and instructions• Can perform billions of tasks per second Can perform billions of tasks per second

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Memory ModuleMemory Module

• Random access memory (RAM)Random access memory (RAM)

• Stores instructions and dataStores instructions and data

• Temporary (volatile) storageTemporary (volatile) storage

• Operates in nanosecondsOperates in nanoseconds

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Expansion CardsExpansion Cards

• Add functionsAdd functions

• Provide new connections for peripheral Provide new connections for peripheral devicesdevices

• Common types:Common types:– SoundSound– ModemModem– Video (VGA)Video (VGA)– Network (NIC)Network (NIC)

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Setting It All Up: ErgonomicsSetting It All Up: Ergonomics

• Ergonomics: minimizing injury or Ergonomics: minimizing injury or discomfort while using the computerdiscomfort while using the computer

• Steps to follow:Steps to follow:– Position monitor correctlyPosition monitor correctly– Use adjustable chairUse adjustable chair– Assume proper position while typingAssume proper position while typing– Take breaksTake breaks– Ensure adequate lightingEnsure adequate lighting

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Chapter 2 Summary QuestionsChapter 2 Summary Questions

• What exactly is a computer, and what are What exactly is a computer, and what are its four main functions? its four main functions?

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• What is the difference between data and What is the difference between data and information?information?

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• What are bits and bytes, and how are they What are bits and bytes, and how are they measured? measured?

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• What devices do you use to get data into What devices do you use to get data into the computer?the computer?

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• What devices do you use to get What devices do you use to get information out of the computer?information out of the computer?

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• What’s on the front of your system unit?What’s on the front of your system unit?

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• What’s on the back of your system unit?What’s on the back of your system unit?

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• What’s inside your system unit?What’s inside your system unit?

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• How do you set up your computer to avoid How do you set up your computer to avoid strain and injury?strain and injury?

Documents

1. 2 Te chnology in Action Chapter 2 Looking at Computers: Understanding the Parts