1. Binary Numbers and ASCII and EDCDIC
Mrs. Cueni

2. Data Representation
Human speech is analog because it uses continuous signals (waves) that vary in strength and quality
Computers are digital – recognize two states ones and zeros, on of off
0 and 1 is called a bit Binary Digit
Smallest unit of information

3. Data representation 8 bits grouped together called a byte
Represent 256 individual characters
Numbers, uppercase, lowercase letters, punctuation marks
Based 2 numbering system

4. Coding Scheme Two popular coding schemes
ASCII – American Standard Code for Information Interchange
EBCDIC – Extended Binary Coded Decimal Interchange Code
Sufficient for English and Western Europe languages
Not large enough for Asian and other languages

5. Coding Sheet ASCII numbers
is the number zero
The first four bits 0011 – identify as a number
The last four digits 0000 determines the number
128 64 32 16 8 4 2 1

6. Binary numbering system
Base 10
4+2+1 = 7
Base 2
107
106
105
104
103
102
101
100
100000
10000
1000 10 1 8 5 6 3 4
85,680,345 27 26 25 24 23 22 21 20
128 64 32 16 8 4 2 1
4+2+1 = 7
8+2 = 10

7. What are these numbers? –

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12. What are these numbers?

13. Coding Sheet ASCII letters
is the letter A
The first two bits 01 – identify as a letter
The last six digits determines the letter as the first letter in the alphabet A

14. How did you do that? 01011010 is the letter Z
The first two bits 01 – identify as a letter
The last digits = =26
26th letter Z
128 64 32 16 8 4 2 1
16+8+2=26

15. Letter order 1st – A 2nd – B 3rd – C 4th – D 5th – E 6th – F 7th- G
8th – H
9th - I
10th – J
11th – K
12th – L
13th- M
14th – N
15th- O
16th - P
17th – Q
18th – R
19th – S
20th – T
21st – U
22nd - V
23rd – W
24th – X
25th – Y
26th - Z

16. What are these letters?

17. Coding Schemes Make it possible to interact with computers
Does this very quickly without you realizing it
Type a character, the computer converts it and processes the data to something it understands
The software converts it back to something we understand

18. Unicode
Many languages use symbols called ideograms to represent multiple words or ideas
Unicode is a 16-bit code that has the capacity of representing more than 65,000 characters and symbols

19. Parity bit Used by computers for error checking Extremely rare
Computers are either odd- or even- parity
Total number of bits on must be even on even-parity computers or odd on odd-parity bit computers
9 bit pattern

20. Transferring data
When computers transfer data from one location to another it checks the sending data and the receiving data to make sure the parity bit is the same
An error is displayed if the parity doesn’t match

21. Hexadecimal
Used for communicating with programmers when a problem exists
0’s and 1’s can be difficult to read
Pass out Hexadecimal chart

22. Hexadecimal Uses 16 symbols to represent values
Hex means six, deci means ten
Conversion between binary and hexadecimal is very efficient
The letter M is in binary
In Hexadecimal 4D
Divide binary number into two sections 0100 and 1101
Convert each section to the hex equivalent 0100 is a 4 and 1101 is letter D
A=10, B=11, C=12, D=13, E=14, F=16

23. Data Storage video
Progressive Insurance video on data storage

24. Binary Conversion Sheet
Complete in class the binary conversion sheet
Worth 26 points
Sources