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

3 Chapter 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

4 Computers Are Data Processing Devices Computer’s four major functions:Computer’s four major functions: –Gathers data (users input data) –Processes data into information –Outputs data or information –Stores data and information

5 Data vs. Information Data: Representation of a fact or ideaData: Representation of a fact or idea Information: Organized, meaningful dataInformation: Organized, meaningful data

6 Bits and Bytes: The Language of Computers Bit – –Binary digit – –0 or 1 Byte – –Eight bits Each letter, number, and character = a string of eight 0s and 1s

7 How Much Is a Byte?

8 Computer Software Software: Programs that enable hardware to perform different tasksSoftware: Programs that enable hardware to perform different tasks –Application software –System software

9 Computer Hardware

10 Input Devices Devices used to enter information or instructions into the computerDevices used to enter information or instructions into the computer –Keyboard –Mouse/ pointing device –Microphone –Scanner –Digital camera –Stylus

11 Keyboards The QWERTY layout is standard on most PCsThe QWERTY layout is standard on most PCs Enhanced keyboard features include number, function, and navigation keys.Enhanced keyboard features include number, function, and navigation keys.

12 Dvorak 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

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

14 Mice Optical mouseOptical mouse –Needs no mouse pad –Doesn’t need cleaning –Is more expensive TrackballTrackball –Easier on wrists –Stays stationary on desk WirelessWireless –Use radio or light waves

15 New Mouse Features Instant viewerInstant viewer MagnifierMagnifier Customizable buttonsCustomizable buttons Web searchWeb search

16 Other Input Devices ScannersScanners –Text –Images Digital camerasDigital cameras –Images –Video Flatbed scanner Handheld scanner Digital camera Camcorder

17 Other Input Devices EPOS Digital PenEPOS Digital Pen Web CamWeb Cam –Live video

18 Inputting Sound Microphones used for:Microphones used for: –Podcasts –Video- conferencing –Internet phone calls –Speech recognition

19 Input Devices for the Physically Challenged Visual impairmentsVisual impairments –Voice recognition –Keyboards with large keys –On-screen keyboards Motor control issuesMotor control issues –Special trackballs –Head-mounted devices

20 Output Devices Send processed data out of the computerSend processed data out of the computer –Monitors –Printers Output devices make:Output devices make: –Soft copies (video, sounds, control signals) –Hard copies (print)

21 Monitor Types CRT Cathode Ray TubeCRT Cathode Ray Tube –Less expensive –Use much more space –Use more energy –Offer better viewing angles –Legacy technology LCD Liquid Crystal Display –More expensive –Use far less space –More energy efficient –Less viewable from an angle

22 Key Monitor Features Screens are grids made up of millions of pixels.Screens are grids made up of millions of pixels. LCDs: Liquid crystal is sandwiched between two transparent layers to form imagesLCDs: Liquid crystal is sandwiched between two transparent layers to form images CRTs: Pixels illuminated by electron beam that passes back and forth across screenCRTs: Pixels illuminated by electron beam that passes back and forth across screen

23 LCD Quality Factors ResolutionResolution Passive vs. active matrix displayPassive vs. active matrix display Viewing angleViewing angle Contrast ratioContrast ratio BrightnessBrightness Response timeResponse time

24 LCD versus CRT LCD monitors:LCD monitors: –take up less space –are generally brighter –cause less eyestrain –use less energy –weigh less CRT monitors:CRT monitors: –used to offer more resolutions –used to produce better color and clarity

25 Other Video Output Touch-screen monitorsTouch-screen monitors –Double as both input and output devices Data projectorsData projectors –Project a computer image to a large screen for sharing with large groups

26 Printers Impact printersImpact printers –Dot-matrix Nonimpact printersNonimpact printers –Inkjet –Laser Specialty printersSpecialty printers –Multifunction –Plotters –Thermal printers

27 Nonimpact Printers InkjetInkjet –Less expensive device – –Print high-quality color images cost effectively Laser –More expensive device –Faster printing speed –Less expensive per page in B&W –Color lasers are becoming less expensive

28 Choosing a Printer Speed (ppm)Speed (ppm) Resolution (dpi)Resolution (dpi) Color outputColor output MemoryMemory Use and costUse and cost Cost of consumablesCost of consumables

29 Outputting Sound Speakers and headphonesSpeakers and headphones

30 The System Unit :Box that contains the central electronic components of the computer: –CPU/RAM/ motherboard –Expansion cards –Power supply –Storage devices

31 The Front Panel Power controlPower control Drive baysDrive bays Memory card readerMemory card reader Productivity portsProductivity ports

32 Power Controls Power-on button: Turns on system, should not be used to turn it off Other options: –Sleep mode –Hibernation –Warm boot

33 Drive Bays Internal drive bays:Internal drive bays: –Cannot be access from outside the system –Reserved for internal hard drives External drive bays:External drive bays: –Can be accessed from outside the system –CD or DVD drives –Floppy and Zip drives

34 Hard Disk Drive Permanent (nonvolatile) storagePermanent (nonvolatile) storage Internal or external versionsInternal or external versions

35 Flash Drives/Flash Memory Flash drives (jump drives)Flash drives (jump drives) –Newer storage alternative –Plug into USB ports Flash memory cardsFlash memory cards –Slide into slots in the system

36 Storage Media Capabilities

37 On the Back Ports for peripheralsPorts for peripherals Types of ports:Types of ports: –Serial and parallel –Audio and video –USB –FireWire –Connectivity EthernetEthernet ModemModem

38 Inside the System Unit Essential electronic components used to process dataEssential electronic components used to process data Types of components:Types of components: –Power supply –Hard disk drive –Motherboard –CPU –Expansion cards

39 The Motherboard CPUCPU RAMRAM Expansion cards and slotsExpansion cards and slots Built-in componentsBuilt-in components

40 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 secondCan perform billions of tasks per second

41 Memory 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

42 Expansion Cards Add functionsAdd functions Provide new connections for peripheral devicesProvide new connections for peripheral devices Common types:Common types: –Sound –Modem –Video (VGA) –Network (NIC)

43 Setting It All Up: Ergonomics Ergonomics: minimizing injury or discomfort while using the computerErgonomics: minimizing injury or discomfort while using the computer Steps to follow:Steps to follow: –Position monitor correctly –Use adjustable chair –Assume proper position while typing –Take breaks –Ensure adequate lighting

44 Chapter 2 Summary Questions What exactly is a computer, and what are its four main functions?What exactly is a computer, and what are its four main functions?

45 Chapter 2 Summary Questions What is the difference between data and information?What is the difference between data and information?

46 Chapter 2 Summary Questions What are bits and bytes, and how are they measured?What are bits and bytes, and how are they measured?

47 Chapter 2 Summary Questions What devices do you use to get data into the computer?What devices do you use to get data into the computer?

48 Chapter 2 Summary Questions What devices do you use to get information out of the computer?What devices do you use to get information out of the computer?

49 Chapter 2 Summary Questions What’s on the front of your system unit?What’s on the front of your system unit?

50 Chapter 2 Summary Questions What’s on the back of your system unit?What’s on the back of your system unit?

51 Chapter 2 Summary Questions What’s inside your system unit?What’s inside your system unit?

52 Chapter 2 Summary Questions How do you set up your computer to avoid strain and injury?How do you set up your computer to avoid strain and injury?