© 2007 Prentice-Hall, Inc.1 Technology In Action

© 2007 Prentice-Hall, Inc.2 Chapter 2 Looking at Computers: Understanding the Parts

© 2007 Prentice-Hall, Inc.3 Topics Hardware componentsHardware components Input devicesInput devices Output devicesOutput devices System unitSystem unit ErgonomicsErgonomics

© 2007 Prentice-Hall, Inc.4 Hardware System UnitSystem Unit Peripheral DevicesPeripheral Devices System Unit Peripheral Devices

© 2007 Prentice-Hall, Inc.5 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

© 2007 Prentice-Hall, Inc.6 Keyboard The QWERTY keyboard with enhanced features is standard with most modern personal computersThe QWERTY keyboard with enhanced features is standard with most modern personal computers

© 2007 Prentice-Hall, Inc.7 Dvorak Keyboard Puts the most commonly used keys at “home keys”Puts the most commonly used keys at “home keys” Reduces distance of finger stretchesReduces distance of finger stretches

© 2007 Prentice-Hall, Inc.8 Specialty Keyboards LaptopsLaptops PDAsPDAs WirelessWireless ErgonomicErgonomic Laptop Ergonomic PDA

© 2007 Prentice-Hall, Inc.9 Mouse Roller ball mouseRoller ball mouse –Less expensive –Harder to keep clean TrackballTrackball –Harder to control –Stationary on desk Optical mouseOptical mouse –Needs no mouse pad –Doesn’t need cleaning –More expensive Wireless Optical Trackball Standard

© 2007 Prentice-Hall, Inc.10 Other Input Devices ScannersScanners –Text –Images Digital camerasDigital cameras –Images –Video Flatbed Handheld Camera Camcorder

© 2007 Prentice-Hall, Inc.11 Inputting Sound Microphone InputMicrophone Input –Teleconferencing –Voice over Internet –Voice Recognition Microsoft Voice Recognition

© 2007 Prentice-Hall, Inc.12 Output Devices Retrieving information from the computerRetrieving information from the computer Output devicesOutput devices –Softcopy (video, sounds, control signals) –Hardcopy (print)

© 2007 Prentice-Hall, Inc.13 Monitor Types CRT Cathode Ray TubeCRT Cathode Ray Tube –Less Expensive –Use much more space –Uses more energy –Better viewing angles LCD Liquid Crystal Display –More expensive –Uses far less space –More energy efficient –Less viewable from an angle

© 2007 Prentice-Hall, Inc.14 CRT Monitors Uses picture tube technologyUses picture tube technology Screen size – Diagonal measurement of the screen (15, 17, 19, 21)Screen size – Diagonal measurement of the screen (15, 17, 19, 21) Resolution – Sharpness of the image determined by the number pixels that the screen can display (800 x 600, 1024 x 768, 1600 x 1200)Resolution – Sharpness of the image determined by the number pixels that the screen can display (800 x 600, 1024 x 768, 1600 x 1200) Refresh rate – Speed at which the screen is refreshed (60Hz, 75Hz) Faster rate equals less flicker.Refresh rate – Speed at which the screen is refreshed (60Hz, 75Hz) Faster rate equals less flicker. Dot pitch – diagonal distance between pixelsDot pitch – diagonal distance between pixels

© 2007 Prentice-Hall, Inc.15 Liquid Crystal Display Liquid crystal sandwiched between two transparent layers form imagesLiquid crystal sandwiched between two transparent layers form images Used for notebook computers, PDAs, cellular phones, and personal computersUsed for notebook computers, PDAs, cellular phones, and personal computers Polarizer Color filter Color filter glass Glass polarizer Backlight Liquid Crystal

© 2007 Prentice-Hall, Inc.16 Dot-matrix Printers Inkjet Multifunction Laser Plotter Thermal printer Impact printersImpact printers –Dot-matrix Non-impact printersNon-impact printers –Inkjet –Laser –Multifunction Specialty printersSpecialty printers –Plotters –Thermal printers

© 2007 Prentice-Hall, Inc.17 Non-impact Printers Ink JetInk Jet –Less expensive device –Full color printing –Slower in pages per minute (PPM) –More expensive per page in B&W Laser –More expensive device –Black and White (Color lasers are very expensive) –Faster in PPM –Less expensive in B&W

© 2007 Prentice-Hall, Inc.18 Choose Printers ResolutionResolution –dpi: dots per inches –300 dpi for general purpose; 600x600 –1200 dpi or above for images Color outputColor output –Ink-jet: 4 or more colors MemoryMemory Use and costUse and cost

© 2007 Prentice-Hall, Inc.19 Outputting Sound Speakers and HeadphonesSpeakers and Headphones

© 2007 Prentice-Hall, Inc.20 The System Unit : Box that contains the central electronic components of the computer: –CPU/RAM/ motherboard –Expansion cards –Power supply –Storage devices

© 2007 Prentice-Hall, Inc.21 The Front Panel Drive BaysDrive Bays Memory card readerMemory card reader Floppy DriveFloppy Drive Productivity PortsProductivity Ports Power ButtonPower Button –Reset, standby –Warm/cold boot

© 2007 Prentice-Hall, Inc.22 The Back Ports for peripheral devicesPorts for peripheral devices Types of ports:Types of ports: –Serial –Parallel –VGA –USB, firewire –Connectivity (modem, network)

© 2007 Prentice-Hall, Inc.23 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

© 2007 Prentice-Hall, Inc.24 The Motherboard CPUCPU RAMRAM Expansion CardsExpansion Cards Chip SetChip Set Built-in componentsBuilt-in components

© 2007 Prentice-Hall, Inc.25 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

© 2007 Prentice-Hall, Inc.26 Memory Module Random access memory (RAM)Random access memory (RAM) Primary storagePrimary storage Stores instructions and dataStores instructions and data Temporary (volatile) storageTemporary (volatile) storage Operates in nanosecondsOperates in nanoseconds Read only memory (ROM) – startup, time, BIOSRead only memory (ROM) – startup, time, BIOS

© 2007 Prentice-Hall, Inc.27 Expansion Cards Adds functionsAdds functions Provides new connections for peripheral devicesProvides new connections for peripheral devices Common types:Common types: –Sound –Modem –Video (VGA) –Network (NIC)

© 2007 Prentice-Hall, Inc.28 Hard Disk Drive Stores data and program instructionsStores data and program instructions Permanent (nonvolatile) storagePermanent (nonvolatile) storage Storage capacities up to 250 GB and higherStorage capacities up to 250 GB and higher Transfers data in millisecondsTransfers data in milliseconds

© 2007 Prentice-Hall, Inc.29 Setting it all up: Ergonomics Ergonomics refers to minimizing injury or discomfort while using the computerErgonomics refers to 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

© 2007 Prentice-Hall, Inc.30 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?

© 2007 Prentice-Hall, Inc.31 Chapter 2 Summary Questions What devices enable us to see or hear the processed information?What devices enable us to see or hear the processed information?

© 2007 Prentice-Hall, Inc.32 Chapter 2 Summary Questions What’s on the front of your system unit?What’s on the front of your system unit?

© 2007 Prentice-Hall, Inc.33 Chapter 2 Summary Questions What’s on the back of your system unit?What’s on the back of your system unit?

© 2007 Prentice-Hall, Inc.34 Chapter 2 Summary Questions What’s inside your system unit?What’s inside your system unit?

© 2007 Prentice-Hall, Inc.35 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?