1. 1 Inside “The Box”

2. 2 CRT Display Keyboard Mouse “The Box” CD-ROM Drive Floppy Disk Drive Computing Devices – Old and New

3. 3 Motherboard

4. 4 CPU (Central Processing Unit)

5. 5 SIMM (Single Inline Memory Module)

6. 6 HDD (Hard Disk Drive)

7. 7 Power Supply

8. 8 Schematic Diagram of a Personal Computer...

9. 9 Ports CPU RAM Disk controller Graphics card Sound card Network card Printer Mouse Keyboard Modem Monitor Speakers bus Computer Schematic Diagram of a Personal Computer...

10. 10 Data Formats Textbook: Chapter 4

11. 11 Figure 3.1 Data conversion and representation Data input

12. 12 Introduction Examples (discreet, continuous) Real World Data Computer Data Input device Dear Mom: Keyboard 10110010… Digital camera 10110010…

13. 13 Format must be Appropriate The internal representation must be appropriate for the type of processing to take place (e.g., text, images, sound) Problem: Since computers store everything in binary code, how does it know what a particular stored item is?

14. 14 Rules/Conventions Proprietary formats –Unique to a product or company –E.g., Microsoft Word, Corel Word Perfect, IBM Lotus Notes Standards –Evolve two ways: Proprietary formats become de facto standards (e.g., Adobe PostScript, Apple Quick Time) Committee is struck to solve a problem (Motion Pictures Experts Group, MPEG) Text : pg 63-64

15. 15 Standards Organizations ISO – International Standards Organization CSA – Canadian Standards Association ANSI – American National Standards Institute IEEE – Institute for Electrical and Electronics Engineers Rv.kc

16. 16 Examples of Standards Type of DataStandards AlphanumericASCII, EBCDIC, Unicode ImageJPEG, GIF, PCX, TIFF Motion pictureMPEG-2, Quick Time,MP4 SoundSound Blaster, WAV, AU,MP3 Outline graphics/fonts PostScript, TrueType, PDF Hint - Learn What kind is which!

17. 17 Why Standards? Standards are “arbitrary” They exist because they are: – Convenient – Efficient – Flexible – Appropriate Plus, they provide some consistency and predictability for applications. Rv.kc

18. 18 Alphanumeric Data Problem: Distinguishing between the number 123 (one hundred twenty-three) and the characters “123” (one, two, three) In software: data is given a type Four Main standards for representing letters (alpha) and numbers –BCD – Binary-coded decimal –ASCII – American standard code for information interchange –EBCDIC – Extended binary-coded decimal interchange code –Unicode

19. 19 Standard Alphanumeric Formats BCD (Binary Coded Decimal) ASCII EBCDIC Unicode

20. 20 Next slides Standard Alphanumeric Formats BCD ASCII EBCDIC Unicode

21. 21 The Problem Representing text strings, such as “ Hello, world”, in a computer After all, computers store binary digits, not letters!

22. 22 Codes and Characters Each character is coded as a byte Most common coding system is ASCII (Pronounced ass-key) ASCII = American National Standard Code for Information Interchange Defined in ANSI document X3.4-1977

23. 23 ASCII Features 7-bit code 8 th bit is unused (or used for a parity bit or to indicate “extended” character set) 2 7 = 128 codes Two general types of codes: –95 are “Graphic” codes (displayable on a console) –33 are “Control” codes (control features of the console or communications channel) R/kc

24. 24 +/Kc Memorize codes for: blank space, period, digit zero (0), capital A, small a, carriage return (CR) Hint

25. 25 ASCII chart

26. 26 e.g., ‘a’ = 1100001 Example: character ‘a’

27. 27 Code types: 95 graphic codes

28. 28 See text page 69 / 71 for details Code types: 33 control codes

29. 29 Code types: alphabetic codes

30. 30 Code types: numeric codes

31. 31 Code types: punctuation codes, etc.

32. 32 “Hello, world” Example ======================== Hexadecimal 48 65 6C 6F 2C 20 77 67 72 6C 64 Decimal 72 101 108 111 44 32 119 103 114 108 100 Hello, worldHello, world ========================

33. 33 Common Control Codes CR0Dcarriage return LF0Aline feed HT09horizontal tab DEL7Fdelete NULL00null Hexadecimal code

34. 34 Common control codes in the table

35. 35 Terminology Names of special symbols [ ] brackets { }braces ( )parentheses @commercial ‘at’ sign & ampersand ~tilde

36. 36 Special symbols in the table

37. 37 Escape Sequences Extend the capability of the ASCII code set For controlling terminals and formatting output Defined by ANSI in documents X3.41-1974 and X3.64-1977 The escape code is ESC = 1B 16 An escape sequence begins with two codes: ESC [ 1B 16 5B 16

38. 38 Examples Erase display:ESC [ 2 J Erase line:ESC [ K

39. 39 Next slides Standard Alphanumeric Formats BCD ASCII EBCDIC Unicode

40. 40 Unicode 16-bit standard Developed by a consortia Intended to supercede older 7- and 8-bit codes

41. 41 Unicode Version 2.1 1998 Improves on version 2.0 Includes the Euro sign (20AC 16 = ) From the standard: …contains 38,887 distinct coded characters derived from the supported scripts. These characters cover the principal written languages of the Americas, Europe, the Middle East, Africa, India, Asia, and Pacifica. http://www.unicode.org

42. 42 Keyboard Input Key (“scan”) codes are converted to ASCII ASCII code sent to host computer Received by the host as a “stream” of data Stored in buffer Processed Etc.

43. 43 Figure 3.7 Keyboard operation Keyboard to binary

44. 44 Shift Key inhibits bit 5 in the ASCII code Key(s) ASCII code 6 5 4 3 2 1 0 Characte r 1 1 0 0 0 0 1 1 0 0 0 0 0 1 aAaA a aShift

45. 45 Control Key inhibits bits 5 & 6 in the ASCII code Key(s) ASCII code 6 5 4 3 2 1 0 Characte r 1 1 0 0 0 1 1 0 0 0 0 0 1 1 c ETX c cCtrl Control code

46. 46 Data Input Devices OCR – optical character recognition Bar code readers Voice/audio input Punched cards Images / objects Pointing devices pp. Old: 69-86 Rev: 72-89

47. 47 OCR Hello, world Page of text Optical scan 10110110… Computer file

48. 48 Data Input Devices OCR – optical character recognition Bar code readers Voice/audio input Punched cards Images / objects Pointing devices pp. 69-86

49. 49 Bar Codes An automatic identification (Auto ID) technology that streamlines identification and data collection See: http://www.digital.net/barcoder/barcode.html

50. 50 Data Input Devices OCR – optical character recognition Bar code readers Pointing devices Punched cards Voice/audio input Images / objects pp. 69-86

51. 51 Pointing Devices Originally used for specifying coordinates (x, y) for graphical input Today used as general purpose device for “graphical user interfaces” (GUIs)

52. 52 Data Input Devices OCR – optical character recognition Bar code readers Pointing devices Punched cards Voice/audio input Images / objects pp. 69-86

53. 53 Punched Cards Invented by Herman Hollerith (founder of IBM) Each card holds 80 characters

54. 54 Image data Typically images are pictures that are optically scanned and saved as a “bit map” or in some other format Many formats –gif, jpeg, … Note: animated gifs often used on www

55. 55 Typical “Save As” Dialog

56. 56 Types of images Bitmaps (raster images) –Examples: photographs, pointing devices –Continuous variation of color, shape, texture –Entered via a scanner or video camera Object images –Created with specialized drawing programs –Set of graphical objects (lines, rectangles, etc.)

57. 57 Bitmap images Made of pixels Require a lot of memory (600 x 800 x 3 = 1.4 MB) Resolution – defines the detail level of the image Involve little processing Formats –GIF (limited to 256 colors) –JPEG (up to 16 Million of colors; use compression)

58. Bitmap Images Used for realistic images with continuous variations in shading, color, shape and texture Preferred when image contains large amount of detail and processing requirements are fairly simple Input devices: –Scanners –Digital cameras and video capture devices –Graphical input devices like mice and pens Managed by photo editing software or paint software 4-58

59. Bitmap Images Each individual pixel, for pi[x]cture element, in a graphic is stored as a binary number –Pixel: A small area with an associated coordinate location –Example: each point below represented by a 4-bit code corresponding to 1 of 16 shades of gray 4-59

60. Bitmap Display Monochrome: black or white –1 bit per pixel Gray scale: black, white or 254 shades of gray –1 byte per pixel Color graphics: 16 colors, 256 colors, or 24-bit true color (16.7 million colors) –4, 8, and 24 bits respectively 4-60

61. 61 Figure 3.10 GIF screen layout GIF format

62. 62 Figure 3.11 GIF file format layout GIF image format

63. JPEG (Joint Photographers Expert Group) Allows more than 16 million colors Suitable for highly detailed photographs and paintings Employs lossy compression algorithm that –Discards data to decreases file size and transmission speed –May reduce image resolution, tends to distort sharp lines 4-63

64. Bitmap vs. Object Images Bitmap (Raster)Object (Vector) Pixel mapGeometrically defined shapes Photographic qualityComplex drawings Paint softwareDrawing software Larger storage requirementsHigher computational requirements Enlarging images produces jagged edges Objects scale smoothly Resolution of output limited by resolution of image Resolution of output limited by output device 4-64

65. Video Images Require massive amount of data –Video camera producing full screen 1024 x 768 pixel true color image at 30 frames/sec 70.8 MB of data/sec –1-minute film clip 4.25 GB storage Options for reducing file size: decrease size of image, limit number of colors, or reduce frame rate Video format determined by a codec, encoder/decoder 4-65 Copyright 2013 John Wiley & Sons, Inc.

66. Video Images Best known codec standards: MPEG-2, MPEG-4, and H.264 –Data may be compressed to 10-60 MB or less of data per minute Container serves as a superstructure to encode, decode, hold and stream the video –Examples: Quicktime from Apple, WebM from Google, and Flash Video from Adobe Streaming video: video displayed in real time as it is downloaded from the Web server 4-66 Copyright 2013 John Wiley & Sons, Inc.

67. Audio Data Transmission and processing requirements less demanding than those for video Analog Waveform: digital representation of sound Analog sound converted to digital values by A- to-D converter MIDI (Musical Instrument Digital Interface): instructions to recreate or synthesize sounds 4-67 Copyright 2013 John Wiley & Sons, Inc.

68. Waveform Audio Sampling rate normally 50KHz 4-68 Copyright 2013 John Wiley & Sons, Inc.

69. Sampling Rate Number of times per second that sound is measured during the recording process. –1000 samples per second = 1 KHz (kilohertz) –Example: Audio CD sampling rate = 44.1KHz Height of each sample saved as: –8-bit number for radio-quality recordings –16-bit number for high-fidelity recordings –2 x 16-bits for stereo 4-69 Copyright 2013 John Wiley & Sons, Inc.

70. Audio Formats MP3 – predominant digital audio data format –Derivative of MPEG-2 (ISO Moving Picture Experts Group) –Uses psychoacoustic lossy compression techniques to reduce storage requirements WAV –Developed by Microsoft as part of its multimedia specification –General-purpose format for storing and reproducing small snippets of sound –Non-compressed 8- or 16-bit sound samples 4-70 Copyright 2013 John Wiley & Sons, Inc.

71. Audio Data Formats 4-71 Copyright 2013 John Wiley & Sons, Inc. WAV file

72. Data Compression Compression: recoding data so that it requires fewer bytes of storage space. Compression ratio: the amount file size is reduced Lossless: inverse algorithm restores data to exact original form –Examples: GIF, PCX, TIFF, ZIP Lossy: trades off data degradation for file size and download speed –Much higher compression ratios, often 10 to 1 –Example: JPEG, MP3 –Common in multimedia H.264: uses both forms for ratios of 1000:1 4-72 Copyright 2013 John Wiley & Sons, Inc.