1. March 2006Taner Erig - EMU2-1 Metamorphosis of Information How is information represented and how do computers store information?

2. March 2006 Taner Erig - EMU2-2 What is Information? n The five types of information the computer commonly manipulates: –Numeric –Character –Visual –Audio –Instructional n First, the information must be transformed (converted) into an acceptable representation that the computer will accept.

3. March 2006 Taner Erig - EMU2-3 What is Information? n Remember, all modern computers work with a system of numbers called binary numbers. Use only two symbols: 0 and 1. n Binary circuits: Electronic devices are cheapest and function most reliably if they assume only two states. Closed circuit Open circuit

4. March 2006 Taner Erig - EMU2-4 Representation of Numbers n The three-light system: Has eight possible combinations of on and off. n Could be used to indicate the numbers 0, 1, 2, 3, 4, 5, 6, 7. 0 = 0004 = 100 1 = 0015 = 101 2 = 0106 = 110 3 = 0117 = 111 Question: How many binary circuits are needed to represent the numbers 0- 15 ? 0-16? 0-48?

5. March 2006 Taner Erig - EMU2-5 Representation of Numbers n Decimal numeration system: Uses 10 symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. The place values of each position designate powers of ten. A number such as 1357 will be expanded as: = (1 x 1000) + (3 x 100) + (5 x 10) + (7 x 1) = 1357 in the decimal system 10 01234 1 100100010000 1 357

6. March 2006 Taner Erig - EMU2-6 Representation of Numbers n Binary numeration system: Uses 2 symbols: 0, and 1. (Each is called a bit for binary digit) The place values of each position are powers of two. A binary number such as 10110 two will be expanded as: = (1 x 16) + (0 x 8) + (1 x 4) + (1 x 2) + (0 x 1) = Only 22 in the decimal system! 22222 01234 124816 01101 <=Power of 2 <=Place value <=Binary

7. There are 10 types of people in this world; those that understand binary and those that don’t!

8. March 2006 Taner Erig - EMU2-8 Representation of Symbols and Text n To store any kind of information in computer memory, it must first be transformed into a binary numeric form. n Symbols and Text Includes characters, punctuation, symbols representing numbers (= all keyboard characters) Each symbol is assigned a binary numeric value. Two standardized sets of codes for symbols: –ASCII: American Standard Code for Information Interchange. See page 37 –EBCDIC: Extended Binary Coded Decimal Interchange Code.

9. March 2006 Taner Erig - EMU2-9 Representation of Symbols and Text n 0 - 0110000 n 1 - 0110001 n 2 - 0110010 n 3 - 0110011 n 4 - 0110100 n 5 - 0110101 n 6 - 0110110 n 7 - 0110111 n 8 - 0111000 n 9 - 0111001 n : - 0111010 n A - 1000001 n B - 1000010 n C - 1000011 n D - 1000100 n E - 1000101 n F - 1000110 n G - 1000111 n H - 1001000 n I - 1001001 n J - 1001010 n K - 1001011 n a - 1100001 n b - 1100010 n c - 1100011 n d - 1100100 n e - 1100101 n f - 1100110 n g - 1100111 n h - 1101000 n i - 1101001 n j - 1101010 n k - 1101011 n Ctrl+@ - 0000000 n Ctrl+A - 0000001 n Ctrl+B - 0000010 n Ctrl+C - 0000011 n Ctrl+D - 0000100 n Ctrl+E - 0000101 n Ctrl+F - 0000110 n Ctrl+G(Bell) - 0000111 n Space - 0100000 n Delete - 1111111 A partial listing of the ASCII character set

10. March 2006 Taner Erig - EMU2-10 Representation of Images n Pictures: A picture must be transformed into numeric form before it can be stored or manipulated by the computer. Each picture is subdivided into a grid of squares called pixels (picture elements). –If the squares are small enough, we will see a reasonably good image. –The more pixels, the higher the resolution!

11. March 2006 Taner Erig - EMU2-11 Representation of Images n In a picture with only black and white pixels: 1 represents black. 0 represents white. 010101010101010101010110101101001001000111110000 011010101010101010101001011010010110010100000110 100101010101010101010110110001010000101001010100 101101101011011010110101100110010110100010001001 011010010110100101101010001001100100101101010010 100101101100101011010101110110011001010010101100 011010010011010110010010001001100110101010010001 010101101100101100100101110110011001010100100101 010101010101010011011010001001100010100001010100 101010101010101100010010110010001101001110100001 010101010101010001000101000101101000010000001101 110110101010010100110100011010010011100101101000 101001010100100010100101100101101100001010000010 101011010001001001001001011110101011010100101100 101010000100010010010111110101111100101001001001 010100101001000100101010101110101011010010010000 101001000010011001101111101011101010101000100101 010010010100100011011000011110111011010110101000 000100000001001100100111111111110110111000000010 101000101010010011011000010101011101000010101000 000010000100101101010011111111111111011101000101 001000101001101010100100011101111110100010010000 010010010110001001001001111011110101101100100101 100100100000111010010010010111111111011001001000 FAX machines use this

12. March 2006 Taner Erig - EMU2-12 Representation of Images n Photographic quality images have a gray-scale. Several shades between black and white are used. 4-level gray-scale means 4 shades are used. –Each pixel needs 2 bits: 4= 2 2 –00 - represents white –01 - represents light gray –10 - represents dark gray –11 - represents black 256 level gray scale means –8 bits per pixel are needed for 256 shades of gray 256= 2 8 256 levels of gray

13. March 2006 Taner Erig - EMU2-13 Representation of Images n Three approaches to display color: n CMYK: Use of four standard colors: cyan, magenta, yellow and black, in the printing industry. n RGB: Uses three values per pixel One number is used for each of the amounts of Red, Green and Blue on the computer screen. n A “Modified” RGB: One number given per pixel to represent all three colors. Full color image 0110 1100 0001

14. March 2006 Taner Erig - EMU2-14 Color on web pages n HTML uses 6 Hexadecimal numbers to designate color: n F F 0 2 0 8 n 16x16x16x16x16x16 possible choices n = 16 6 OR 2 24 16 million colors or think of the number as n each screen pixel uses 24 bits to describe it! Counting in Hexadecimal: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F and needs only 4 bits to store a hexadecimal number. 10 hex = 16 11 hex = 17 etc.

15. March 2006 Taner Erig - EMU2-15 Representation of Sounds, Music and Speech n Sounds, Music and Speech: Each sound must be transformed into numeric form before it can be stored or manipulated by the computer.

16. March 2006 Taner Erig - EMU2-16 What is Information? n Review The five types of information the computer commonly manipulates are: –Numeric –Character –Visual –Audio and –Instructional

17. March 2006 Taner Erig - EMU2-17 Representing the Instructions of Programs n A computer’s instructions must be stored in binary form within the computer before they can be used. Program: A collection or list of commands designed for a computer to follow, which gives some desired result. Instruction set: The pre-determined list of commands that comprise all of the possible instructions needed to perform a particular task. Often defined by the hardware of the computer, one for each possible task, often relate to a circuit. needed to operate the computer.

18. March 2006 Taner Erig - EMU2-18 Word Hunt ~ Assembly Program n A Word Hunt program example: GOTO7 <-- go to page # 7 SELECT3 <-- line #3 FORWARD15<-- count over to word 15 WRITEword <-- write the word SELECT5 <-- now go to line #5 FORWARD12 and so on WRITEword GOTO14 SELECT30 FORWARD4 WRITEword Operands BACKUP3 WRITEword STOP Opcodes

19. March 2006 Taner Erig - EMU2-19 Representing the Instructions of Programs n 1 GOTO # n 2 SELECT # n 3 FORWARD # n 4 BACKUP# n 5 WRITE word n 0 STOP GOTO7 SELECT3 FORWARD15 WRITEword SELECT5 FORWARD12 WRITEword GOTO14 SELECT30 FORWARD4 WRITEword BACKUP3 WRITEword STOP 1 7 23 315 5 25 312 5 1 14 230 34 5 4 3 5 0 001 00111 01000011 01101111 101 01000101 01101100 101 00101110 01011110 01100100 101 10000011 101 000 Word Hunt Word Hunt ProgramProgram Instruction Set:Programin decimalin binary

20. March 2006 Taner Erig - EMU2-20 Representing the Instructions of Programs n All instructions must have: Opcode (Operation Code): The part of the instructions that tells the computer what to do. Operand: The “object” of the operation to be performed. –Example: If the operation is to add a number, then the operand will tell where to find the number that is to be added. 0 1 0 1 1 0 1 0 Code for addition Memory address of the number to be added

21. March 2006 Taner Erig - EMU2-21 Representing the Instructions of Programs n How can the computer tell what this string of binary numbers is used for? 01011010 two An instruction? A number? A sound’s frequency? The value of a pixel in a gray-scale image? An ASCII character? n It is the running program that determines the interpretation of the string of binary numbers!