1. Representing Information Digitally

2. Digitization Initially transforming data for computer use Assigning people social security numbers The creation of telephone numbers Encoding information became the way to transform the real world into a context that the computer could understand

3. Information Metamorphosis n Fitting the real world into the computer n Computer’s world –Electronic –Fast –Binary n Real World –Multiple forms of data / information –Imprecise / vague –Non uniform speeds

4. Information Metamorphosis n Real World Data Forms –Numeric Data –Character Data –Graphical / Visual Data –Audio Data –Instructional Data n Methodology needed to transform real world data into computer world (binary)

5. Binary Number System n A decimal number: 1,648,319 1,648,319 n A binary number: 1001 1101

6. Binary Number System n Binary for numeric data n Binary digit = Bit n 8 Bits = Byte –Smallest addressable unit within the computer n 4 Bytes = Word –Basic unit for arithmetic –Contains 32 bits n Converting from binary

7. Numeric Data

8. n Converting to binary –Repeated division by 2 –Remainders are the important part –Read from bottom up as if left to right

9. Character Data n Binary for Character Data –8 bit combinations assigned to a symbol –Name for mapping process is ASCII table

10. ASCII, The American Standard Code for Information Interchange

11. Graphical Data n Binary for Graphical Data

12. Graphical Data n Binary for Graphical Data

13. Graphical Data n Binary for Graphical Data n Each black pixel is represented as a “1” n Each white pixel is represented as a “0” n Pixels are grouped in units of 8 so they can be stored in 1 byte

14. Graphical Data A 1” picture scanned at 150 DPI (dots per inch) Total size = 150 X 150  22,500 dots Memory required = 22,500 / 8  2,813 bytes Color requires more bits to represent each dot Using 8 bits for each dot allows for 256 different colors The 1” picture now requires 22,500 bytes

15. Graphical Data n Printers are rated in DPI for print quality n Scanners are rated in DPI for image resolution n Monitors / displays have display settings for display resolution –800 X 600 –1024 X 768 –1280 X 1024 –1400 X 1050

16. Audio Data n Binary for audio data n Sound as a waveform –Y-axis represents voltage –X-axis represents time n Suppose the wave form shown represents 1 second of sound

17. Audio Data n Divide Sample into segments

18. Audio Data n Divide Sample into more segments

19. Audio Data n Divide Sample into even more segments

20. Audio Data n The more segments the better the re-created wave form n The given sample was divided into 34 segments (approx) n An Audio CD utilizes 44,000 samples per second of sound

21. Instructional Data n Binary for Instructional Data n Instructional Data has not only content but sequence n Driving directions to NJ Aquarium –Designated number of steps –Sequence of steps is critical to success –Rearranging sequence will not get you to the NJ Acquarium n Recipe / Directions / Program

22. Instructional Data n Word Hunt Instruction Set –Similar to “decoder ring” n Six instructions –GOTO # –SELECT # –FORWARD # –BACKUP # –WRITE –STOP

23. Instructional Data n A program is a collection of instructions n Executing the program means to “carry out” the listed instructions n GOTO# - turn to designated page n SELECT# - count down this many lines n FORWARD# - count in this many words

24. Instructional Data n Real computers have different types of instructions –Arithmetic –Data Movement –Logical / Comparison –Control –Input / Output