7-1 IS 2101 Fall 2010 Chapter 2 Looking at Computers: Understanding the Parts

2 Chapter Topics Functions of a computer Data versus information Bits and bytes Input devices Output devices System unit Ergonomics

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

4 Data vs. Information Data: Representation of a fact or idea Information: Organized, meaningful data

Bits and Bytes: The Language of Computers Bit  Binary digit  0 or 1 Byte  8 bits Each letter, number, and character = a string of eight 0s and 1s 5

6 How Much Is a Byte?

7 Computer Software Software: Programs that enable hardware to perform different tasks  Application software  System software

8 Computer Hardware

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

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

11 Dvorak Keyboards Puts the most commonly used keys on “home keys” Reduces distance of finger stretches

12 Specialty Keyboards Notebook keyboard PDA stylus Tablet PCs Wireless keyboard

13 Mice Optical mouse  Needs no mouse pad  Doesn’t need cleaning  Is more expensive Trackball  Easier on wrists  Stays stationary on desk Wireless  Use radio or light waves

14 New Mouse Features Instant viewer Magnifier Customizable buttons Web search

15 Other Input Devices Scanners  Text  Images Digital cameras  Images  Video Flatbed scanner Handheld scanner Digital camera Camcorder

16 Other Input Devices EPOS Digital Pen Web Cam  Live video

17 Inputting Sound Microphones used for:  Podcasts  Video-conferencing  Internet phone calls  Speech recognition

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

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

20 Monitor Types CRT 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

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

22 LCD Quality Factors Resolution Passive vs. active matrix display Viewing angle Contrast ratio Brightness Response time

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

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

25 Printers Impact printers  Dot-matrix Nonimpact printers  Inkjet  Laser Specialty printers  Multifunction  Plotters  Thermal printers

26 Nonimpact Printers Inkjet  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

27 Choosing a Printer Speed (ppm) Resolution (dpi) Color output Memory Use and cost Cost of consumables

28 Outputting Sound Speakers and headphones

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

30 The Front Panel Power control Drive bays Memory card reader Productivity ports

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

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

33 Hard Disk Drive Permanent (nonvolatile) storage Internal or external versions

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

35 Storage Media Capabilities

36 On the Back Ports for peripherals Types of ports:  Serial and parallel  Audio and video  USB  FireWire  Connectivity Ethernet Modem

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

38 The Motherboard CPU RAM Expansion cards and slots Built-in components

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

40 Memory Module Random access memory (RAM) Stores instructions and data Temporary (volatile) storage Operates in nanoseconds

41 Expansion Cards Add functions Provide new connections for peripheral devices Common types:  Sound  Modem  Video (VGA)  Network (NIC)

Specialty Computers Mainframes Supercomputers Embedded computers 42

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

Ergonomics and Mobile Devices Mobile devices present ergonomic challenges Ergonomic “Disease”Cause Blackberry thumbThumb typing without breaks or stretching can cause DeQuervains’ tendinitis in the thumbs. iPod deafnessListening through ear buds for prolonged periods at a volume of 80 decibels or more can cause deafness. Cellular blindnessExtended viewing on tiny screens can cause eye strain and/or dry eyes. Laptop thighsResting a laptop directly on your lap for extended periods of time can result in 1 st and 2 nd degree burns. Laptop shoulderLarge, heavy, one-strap laptop bags can result in neck, shoulder, and back pain and/or strain. 44

45 Chapter 3 Summary Questions What exactly is a computer, and what are its four main functions?

46 Chapter 3 Summary Questions What is the difference between data and information?

47 Chapter 3 Summary Questions What are bits and bytes, and how are they measured?

48 Chapter 3 Summary Questions What devices do you use to get data into the computer?

49 Chapter 3 Summary Questions What devices do you use to get information out of the computer?

50 Chapter 3 Summary Questions What’s on the front of your system unit?

51 Chapter 3 Summary Questions What’s on the back of your system unit?

52 Chapter 3 Summary Questions What’s inside your system unit?

53 Chapter 3 Summary Questions How do you set up your computer to avoid strain and injury?