1. 1 Chapter Topics Chapter 2 Looking at Computers: Understanding the Parts 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

2. 2 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

3. 3 Data vs. Information Data: Representation of a fact, figure, or idea Information: Organized, meaningful data Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

4. 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. 5 How Much Is a Byte? Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall NameAbbreviationNumber of BytesRelative Size ByteB1 byteCan hold one character of data. KilobyteKB1,024 bytes (2 10 bytes)Can hold 1,024 characters or about half of a double-spaced typewritten page. MegabyteMB1,048,576 bytes (2 20 bytes)Can hold approximately 768 pages of typed text. GigabyteGB1,073,741,824 bytes (2 30 bytes)Approximately 786,432 pages of text; 500 sheets of paper is approximately 2 inches, so this represents a stack of paper 262 feet high. TerabyteTB1,099,511,627,776 bytes (2 40 bytes)This represents a stack of typewritten pages almost 51 miles high. PetabytePB1,125,899,906,842,62 bytes (2 50 bytes) The stack of pages is now 52,000 miles high, or approximately one- fourth the distance from the Earth to the moon. ExabyteEB1,152,921,504,606,846,976 bytes (2 60 bytes) The stack of pages is now 52 million miles high, or just about twice the distance between the Earth and Venus. ZettabyteZB1,180,591,620,717,411,303,424 bytes (2 70 bytes) The stack of pages is now 52 billion miles high, some 20 times the distance between the Earth and Pluto.

6. Metric prefixes prefixabbrev#word -- B1 byte kiloKB1,000 bytesthousand megaMB1,000,000 bytesmillion gigaGB1,000,000,000 bytesbillion teraTB1,000,000,000,000 bytesTrillion petaPB1,000,000,000,000,000 bytesquadrillion 6

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

8. 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. 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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

10. 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. 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. 12 Notebook Keyboard trackpointtrackpoint touchpadtouchpad number padnumber pad Notebook keys – fn key in conjunction with function key does special function such as volumeNotebook keys – fn key in conjunction with function key does special function such as volume trackpoint Touchpad Fn key

13. 13 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 Not enough interest to change from QWERTY thoughNot enough interest to change from QWERTY though

14. Virtual laser, Tablet and stylus Virtual laser keyboard Configurable keyboard Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 14

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

16. © 2008 Prentice-Hall, Inc. 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)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 wirelessBluetooth wireless keyboard is a shorter range wireless RF keyboard

17. 17 Mice Optical mouseOptical mouse –Doesn’t need as dirty –no mouse pad necessary TrackballTrackball –Easier on wrists –Stays stationary on desk WirelessWireless –Use radio or light waves Integrated pointing deviceIntegrated pointing device –Touchpad –Trackpoint

18. 18 Other Input Devices ScannersScanners –Text –Images Digital camerasDigital cameras –Images –Video Flatbed scanner Handheld scanner Digital camera Camcorder

19. 19 Other Input Devices Game controllers Touchscreens – –DS game – –Tablet PC (see pic) Digital pens Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

20. 20 Image Input Digital cameras, camcorders, and cell phones – –Pictures – –Video Webcams – –Live video Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

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

22. 22 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

23. 23 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)

24. © 2008 Prentice-Hall, Inc. 24 Monitor Types and advantages CRT Cathode Ray Tube –Less expensive –Better viewing angles –More adjusting allowed of of the resolution settings –Better color accuracy –Preferred for gaming –A 17” monitor IS less than17” –legacy LCD Liquid Crystal Display –Price is dropping –Uses far less space –More energy efficient –More environmentally friendly –Less eye strain –A 17’’ monitor IS 17” –brighter

25. Screens are grids made up of millions of pixels.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 scrnLCDs: 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.) 25 LCD Monitor Features

26. 26 LCD Quality Factors (recommended measures in parentheses) : Resolution - depends on # of pixels on screen; (native resolution is the maximum resolution)Resolution - depends on # of pixels on screen; (native resolution is the maximum resolution) Viewing angle - poorer angles than the CRT (degrades after 150 degrees)Viewing angle - poorer angles than the CRT (degrades after 150 degrees) Contrast ratio - Diff between brightest white & darkest black (400:1 or 1000:1)Contrast ratio - Diff between brightest white & darkest black (400:1 or 1000:1) Brightness - amt of light when showing pure white (300 cd/m 2 )Brightness - amt of light when showing pure white (300 cd/m 2 ) Response time – time for pixel to change color (smaller # better; for movies, games)Response time – time for pixel to change color (smaller # better; for movies, games)

27. 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) Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

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

29. 29 Printers Impact printersImpact printers –Dot-matrix Nonimpact printersNonimpact printers –Inkjet –Laser Specialty printersSpecialty printers –All-in-one –Plotters –Thermal printers

30. 30 Nonimpact Printers Inkjet – –Less expensive device – –Print high-quality color images cost effectively Laser –More expensive device –Faster printing speed –Color lasers are becoming less expensive Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

31. © 2008 Prentice-Hall, Inc. 31 Nonimpact Printers Inkjet and Laser Inkjet (spray tiny drops of ink. )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 When purchasing a printer consider price of consumables (ex: cartridges and toner), speed (ppm, pages per minute), resolution (dpi, dots per inch), memory, color

32. 32 The Motherboard CPUCPU RAM (S+T)RAM (S+T) Expansion cards and slotsExpansion cards and slots Built-in componentsBuilt-in components

33. 33 Expansion Cards Add functionsAdd functions Provide new connections for peripheral devicesProvide new connections for peripheral devices Common types:Common types: –Sound –Modem (telephone) –Video (VGA or graphics) –Network (NIC=network interface card)

34. 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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 34

35. 35 Memory Module Random access memory (RAM)Random access memory (RAM) Stores instructions and data temporarilyStores instructions and data temporarily –(copy of program instructions and current files goes into RAM) Temporary (volatile) storageTemporary (volatile) storage Operates in nanosecondsOperates in nanoseconds Common size: 2-8GBCommon size: 2-8GB

36. 36 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 Common speed: 2-3 ghz (gigahertz)Common speed: 2-3 ghz (gigahertz) 3 ghz = ~ 3 billion machine cycles per sec3 ghz = ~ 3 billion machine cycles per sec

37. 37 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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

38. 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) Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 38

39. 39 The Front Panel Power controlPower control Drive baysDrive bays Memory card readerMemory card reader Productivity portsProductivity ports

40. 40 Hard Drive Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall Permanent storagePermanent storage Internal or external versionsInternal or external versions Stores data, program instructions as they are runningStores data, program instructions as they are running (Completes tasks in millisecs vs RAM’s nanosecs.)(Completes tasks in millisecs vs RAM’s nanosecs.) (Spin rate: 5400, 7200 rpm)(Spin rate: 5400, 7200 rpm) Common: 500 GB, 640 GB, 1TB, 2TBCommon: 500 GB, 640 GB, 1TB, 2TB –(T=Tera, trillion)

41. Optical Storage Compact discs (CDs) Digital video discs (DVDs) Blu-ray discs (BDs) Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 41

42. Storage Media Capabilities See p71 (8e), teacher notes 42 Typo: DVD DL is 8.5 GB not 88.5

43. 43 Flash Drives/Flash Memory Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall Flash drives (jump drives) – –Newer storage alternative – –Plug into USB ports Flash memory cards – –Slide into slots in the system

44. 44 Types of Ports USB Serial and parallel Audio and video FireWire Connectivity – –Ethernet – –Modem Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

45. © 2008 Prentice-Hall, Inc. 45 Ports for peripheral devices Types of ports w/ speeds (= transfer rates): –Serial 115K bps, –Parallel 500K bps –USB 480M bps (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

46. Adding Ports Expansion cards: – –New port standards Expansion hubs: – –Enable several devices to be connected to a port Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 46

47. 47 Power Controls Power-on button: Turns on system; 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 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

48. © 2008 Prentice-Hall, Inc. 48 Ergonomics (1) Ergonomics – procedures, equipment for minimizing injury or discomfort while using the computer (minimize RSI - repetitive stress injury)Ergonomics – procedures, equipment for minimizing injury or discomfort while using the computer (minimize RSI - repetitive stress injury) Steps to follow: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

49. © 2008 Prentice-Hall, Inc. 49 Ergonomics (2) Play PMPs (personal media players) at 60 decibels or lessPlay PMPs (personal media players) at 60 decibels or less Small screens – blink often, take a break to focus at 8ftSmall screens – blink often, take a break to focus at 8ft Backpack – place over both shoulders not oneBackpack – place over both shoulders not one

50. 50 Chapter 2 Summary Questions What are the 4 main functions of a computer?What are the 4 main functions of a computer? What is the difference between data and information?What is the difference between data and information? What are bits and bytes, and how are they measured?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 data into the computer? What devices do you use to get information out of the computer?What devices do you use to get information out of the computer? What’s on the motherboard?What’s on the motherboard? Where are programs and information stored?Where are programs and information stored? How are devices connected to the computer?How are devices connected to the computer? How do you set up your computer to avoid strain and injury?How do you set up your computer to avoid strain and injury?