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Chapter Topics

Chapter Topics. Chapter 2 Looking at Computers: Understanding the Parts Functions of a computer Data versus information Bits and bytes Input devices Output devices System unit Ergonomics. Computers Are Data Processing Devices. Computer’s four major functions:

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Chapter Topics

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  1. Chapter Topics Chapter 2 Looking at Computers: Understanding the Parts • Functions of a computer • Data versus information • Bits and bytes • Input devices • Output devices • System unit • Ergonomics

  2. Computers Are Data Processing Devices • Computer’s four major functions: • Inputs (user inputs data) • Processes data into information • Outputs data or information • Stores data and information

  3. Data vs. Information • Data: Representation of a fact, figure, or idea • Information: Organized, meaningful data

  4. 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

  5. How Much Is a Byte?

  6. Metric prefixes

  7. Computer Hardware Hardware: Any part of the computer you can touch.

  8. Computer Software • Software: Programs that enable hardware to perform different tasks • Application software • System software

  9. Types of Computers • Notebook: Portable computer • Desktop: Used at a single location • Mainframe: Supports hundreds of users simultaneously • Supercomputer: Performs complex calculations rapidly • Embedded: Self-contained computer performing dedicated functions

  10. Input Devices • Devices 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 PCs • Enhanced keyboard features include number, function, and navigation keys.

  12. Notebook Keyboard • trackpoint • touchpad • number pad • Notebook keys – fn key in conjunction with function key does special function such as volume trackpoint Fn key Touchpad

  13. Dvorak Keyboards • Puts the most commonly used keys on “home keys” • Reduces distance of finger stretches • Not enough interest to change from QWERTY though

  14. Virtual laser, Tablet and stylus • Virtual laser keyboard • Configurable keyboard

  15. Digital pen • Stores what you “write”, later transfer to computer

  16. Wireless RF keyboard • With the RF (radio frequency) wireless technology, the keyboard contains a transmitter that transmits the radio waves to a receiver that sits next to the keyboard and is attached to the tower. (upto 100 ft) • Bluetooth wireless keyboard is a shorter range wireless RF keyboard

  17. Mice • Optical mouse • Doesn’t need as dirty • no mouse pad necessary • Trackball • Easier on wrists • Stays stationary on desk • Wireless • Use radio or light waves • Integrated pointing device • Touchpad • Trackpoint

  18. Other Input Devices • Scanners • Text • Images • Digital cameras • Images • Video Flatbed scanner Handheldscanner Digital camera Camcorder

  19. Other Input Devices • Game controllers • Touchscreens • DS game • Tablet PC (see pic) • Digital pens

  20. Image Input • Digital cameras, camcorders, and cell phones • Pictures • Video • Webcams • Live video

  21. Inputting Sound • Microphones used for: • Podcasts • Video-conferencing • Internet phone calls • Speech recognition

  22. 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

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

  24. CRT Cathode Ray Tube Legacy (as in “old”) LCD Liquid Crystal Display Uses far less space More energy efficient More environmentally friendly Less eye strain A 17’’ monitor IS 17” brighter Monitor Types and advantages

  25. LCD Monitor Features • Screens are grids made up of millions of pixels. • (pixel = picture elements, dots on screen) • Each pixel is composed of red, blue, and green subpixels • LCDs: Liquid crystal, light waves, etc result in variations of red, green blue colors of images formed n scrn (CRTs: Pixels illuminated by electron beam that passes back/forth across screen.)

  26. LCD Quality Factors (recommended measures in parentheses) : • Resolution - depends on # of pixels on screen; (native resolution is the maximum resolution) • Viewing angle - poorer angles than the CRT (degrades after 150 degrees) • Contrastratio - Diff between brightest white & darkest black (400:1 or 1000:1) • Brightness - amt of light when showing pure white(300 cd/m2) • Response time – time for pixel to change color (smaller # better; for movies, games)

  27. Screen Size • 21” monitor: 1680x1050 pixels (typical resolution) • 19” monitor: Some resolutions: 1440x900, 1280x1024 • Need 1920x1080 for hi-def movies • Wide screen vs. standard 4:3 ratio; wide good for 2 documents viewed at once... • Large resolution fits more on screen (images are smaller); Small res fits less (images are larger)

  28. Other Video Output • Touch-screen monitors • Double as both input and output devices • Monitors w/ built-in cam, mic, card reader, USB hub • Data projectors • Project a computer image to wall for sharing with group

  29. Printers • Impact printers • Dot-matrix • Nonimpact printers • Inkjet • Laser • Specialty printers • All-in-one • Plotters • Thermal printers

  30. Inkjet (spray tiny drops of ink. ) Entry level model is less expensive Full color printing – excellent choice for photo printing Laser (uses toner) There are B & W laser printers and color laser printers (Color lasers very expensive) Excellent quality, quiet Nonimpact PrintersInkjet and Laser • When purchasing a printer consider price of consumables (ex: cartridges and toner), speed (ppm, pages per minute), resolution (dpi, dots per inch) , memory, color

  31. The Motherboard • CPU • RAM (S+T) • Expansion cards and slots • Built-in components

  32. Expansion Cards • Add functions • Provide new connections for peripheral devices • Common types: • Sound • Modem (telephone) • Video (VGA or graphics) • Network (NIC=network interface card)

  33. RAM vs. ROM • Random access memory (RAM): • Stores instructions and data • Temporary (volatile) storage • Consists of several memory cards or modules • Read-only memory (ROM): • Stores start-up instructions • Permanent storage

  34. Memory Module • Random access memory (RAM) • Copy of program instructions/data in RAM when program running • Temporary (volatile) storage • Operates in nanosec. • Common size: • (see chap 6: 4GB at least; high end computer may have 24GB)

  35. 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 • Common speeds: 2-4 GHz (Gigahertz) (discussed also in chapter 6) • 3 GHz = ~ 3 billion machine cycles per sec

  36. CPU Performance Measures • Speed - common 2-3 ghz • 3 GHz ~ 3 billion machine cycles per sec • Megahertz (MHz) • Gigahertz (GHz); • Cores (simultaneous paths executing instruct’s; see picture on right) • Single • Dual • Quad

  37. Drive Bays • Internal drive bays: • Cannot be accessed from outside the system • Are reserved for internal hard drives • External drive bays: • Can be accessed from outside the system • CD or DVD drives • Floppy and Zip drives (legacy technology)

  38. The Front Panel • Power control • Drive bays • Memory card reader • Productivity ports

  39. Hard Drive • Permanent storage • Internal or external versions • Stores data, program instructions as they are running • (Completes tasks in millisecsvs RAM’s nanosecs.) • (Spin rate: 5400, 7200 rpm) • Common: 500 GB, 640 GB, 1TB, 2TB • (T=Tera, trillion)

  40. Optical Storage • Compact discs (CDs) • Digital video discs (DVDs) • Blu-ray discs (BDs)

  41. StorageMediaCapabilities See p71 (8e), teacher notes Typo: DVD DL is 8.5 GB not 88.5

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

  43. Types of Ports • USB • Serial and parallel • Audio and video • FireWire • Connectivity • Ethernet • Modem

  44. Ports for peripheral devices • Types of ports w/ speeds (= transfer rates): • Serial 115K bps, • Parallel 500K bps • USB 480Mbps (2.0) • USB 4800M bps (3.0) • Ethernet 100M,1000M bps • Tele. modem 56K bps • FireWire (or 1394) • 400M bps, 800M bps, and • 3.2G bps (= 3200M bps) • Audio ports • VGA (monitor), DVI, s-video • HDMI

  45. Adding Ports • Expansion cards: • New port standards • Expansion hubs: • Enable several devices to be connected to a port

  46. Power Controls Power-on button: Turns onsystem; Use Shut Down procedure or may use Power button to turn off. • Called a cold boot when turned on for the first time that day (Warm boot is restart) • Keep computer on but use conservation of energy:Sleep mode, Hibernate • Only turn off computer if use it very little • Change power settings: Control Panel (icon view) > Power Options

  47. Ergonomics (1) • Ergonomics – procedures, equipment for minimizing injury or discomfort while using the computer (minimize RSI - repetitive stress injury) • Steps to follow: • Position monitor correctly (eyse at top of monitor) • Use adjustable chair (back of knees not pressed against chair that is too high, feet on floor) • Wrists flat over keyboard, not presses on edge of table • Take breaks • Ensure adequate lighting

  48. Ergonomics (2) • Play PMPs (personal media players) at 60 decibels or less • Small screens – blink often, take a break to focus at 8ft • Backpack – place over both shoulders not one

  49. Chapter 2 Summary Questions • What are the 4 main functions of a computer? • What is the difference between data and information? • What are bits and bytes, and how are they measured? • What devices do you use to get data into the computer? • What devices do you use to get information out of the computer? • What’s on the motherboard? • Where are programs and information stored? • How are devices connected to the computer? • How do you set up your computer to avoid strain and injury?

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