1. Looking Inside the Black Box
Input
Output
CPU
Storage
Secondary - Hard Drives
Primary - RAM, ROM

2. Storing Data Computers store Digital Data Two type of data
Digital – can be compressed
Analog
Digital data – stored as digital data
Text data – stored as ASCII codes (digital)
Analog data – converted to digital

3. Storing Data – Binary Numbers

4. Storing Data – Binary Numbers

5. Storing Data – Binary Numbers
Used to store digital data
8 bits
0 =
1 =
2 =
...
254 =
255 =
16 bits
0 =
1 =
2 =
...
65534 =
65535 =

6. Storing Data – Hexadecimal
Easy way to represent binary numbers
Easy to convert between hex and binary
Base 16
0 = 0000
1 = 0001
2 = 0010
3 = 0011
4 = 0100
5 = 0101
6 = 0110
7 = 0111
8 = 1000
9 = 1001
A = 1010
B = 1011
C = 1100
D = 1101
E = 1110
F = 1111

7. Storing Data – ASCII Used to store text based DIGIT 1 2 3 4 5 6 7 8 91 2 3 4 5 6 7 8 9
ASCII REPRESENTATION
LETTER A B C D E F G H I
ASCII REPRESENTATION

8. 32      blank      65       A         66       B         67       C         68       D         69       E         70       F         71       G         72       I         73       I         74       J         75       K         76       L         77       M         78       N         79       O         80       P         81       Q         82       R         83       S         84       T         
   97       a          98       b          99       c         100       d         101       e         102       f         103       g         104       h         105       i         106       j         107       k         108       l         109       m         110       n         111       o         112       p         113       q         114       r         115       s         116       t         117       u        

9. ASCII
Full ASCII Table
F o u r a n d s e v e n

10. Storing Data – Analog Data
Must be converted to Digital
Sample demo

11. Converting Between Number Systems
Binary to Decimal
Decimal to Binary
Binary to Hex
Hex to Binary

12. Converting Between Number Systems
Decimal
Binary

13. Converting Between Number Systems
Binary >Decimal
> decimal
> decimal
Decimal > Binary
128 > binary
100 > binary
Hex > Binary
1A > binary
0F > binary
Binary > Hex
> hex
> hex
ASCII > Decimal
A > decimal
a > decimal
Decimal > ASCII
> ascii
> ascii

14. Coding Data for Processing by a Computer
Pixels
Data Compression
Lossy - examples
Lossless - examples
?Examples of file types

15. Data Compression Binary Data Compressed Data \
12 bytes
Compressed Data
4, ,255
5 bytes

16. Compression Examples BMP (422kb)

17. Compression Examples JPG 10% (66kb)

18. Compression Examples JPG 85% (15kb)

19. Compression - LZ Lempel – Ziv WinZip
Dictionary to eliminate redundancy
From - HowStuffWorks.com

20. Compression - LZ Example
"Ask not what your country can do for you -- ask what you can do for your country.“ = 79 chrs
Dictionary:
ask
what
your
country
can do
for
you
“1 not " = 37 chrs
From - HowStuffWorks.com

21. Compression - LZ Plus Dictionary = 37, Total = 74 vs 79
Real LZ uses patterns not words
ask__
what__
you
r__country
__can__do__for__you
"1not__ " = 16 chrs
Dictionary = 41, Total = 57
From - HowStuffWorks.com