Binary Numbers and ASCII and EDCDIC Mrs. Cueni
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
Data representation 8 bits grouped together called a byte Represent 256 individual characters Numbers, uppercase, lowercase letters, punctuation marks Based 2 numbering system
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
Coding Sheet ASCII numbers 00110000 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
Binary numbering system Base 10 4+2+1 = 7 Base 2 107 106 105 104 103 102 101 100 10000000 1000000 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
What are these numbers? 00110101 –
What are these numbers? 00110011 –
What are these numbers? 00111001 –
What are these numbers? 00110111 –
What are these numbers? 00110110 –
What are these numbers? 00111111
Coding Sheet ASCII letters 01000001 is the letter A The first two bits 01 – identify as a letter The last six digits 000001 determines the letter as the first letter in the alphabet A
How did you do that? 01011010 is the letter Z The first two bits 01 – identify as a letter The last digits 011010 = 16+8+2=26 26th letter Z 128 64 32 16 8 4 2 1 16+8+2=26
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
What are these letters? 01000001 01010111 01001010 01010101
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
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
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
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
Hexadecimal Used for communicating with programmers when a problem exists 0’s and 1’s can be difficult to read Pass out Hexadecimal chart
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 01001101 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
Data Storage video Progressive Insurance video on data storage
Binary Conversion Sheet Complete in class the binary conversion sheet Worth 26 points Sources http://www.computerhope.com/binhex.htm