ASCII data formats
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ASCII data formats to show data in computer.
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ASCII data formats
- 1. 2. Data Formats Data Representation Introduction to Information Technologies
- 2. Introduction • Examples Computer Real World Data Input device Data Dear Mom: Keyboard 10110010… Digital camera 10110010… pp. 59.-61 Data Representation Introduction to Information Technologies
- 3. Format must be appropriate • The internal representation must be appropriate for the type of processing to take place (e.g., text, images, sound) Data Representation Introduction to Information Technologies
- 4. Standards Organizations • ISO – International Standards Organization • CSA – Canadian Standards Association • ANSI – American National Standards Institute • IEEE – Institute for Electrical and Electronics Engineers • Etc. Data Representation Introduction to Information Technologies
- 5. Examples of Standards Type of Data Alphanumeric Standards ASCII, EBCDIC, Unicode Image JPEG, GIF, PCX, TIFF Motion picture MPEG-2, Quick Time Sound Sound Blaster, WAV, AU Outline graphics/fonts PostScript, TrueType, PDF Data Representation Introduction to Information Technologies
- 6. The Problem • Representing text strings, such as “Hello, world”, in a computer Data Representation Introduction to Information Technologies
- 7. Codes and Characters • Each character is coded as a byte • Most common coding system is ASCII (Pronounced ass-key) • ASCII = American National Standard Code for Information Interchange Data Representation Introduction to Information Technologies
- 8. ASCII Features • • • • 7-bit code 8th bit is unused (or used for a parity bit) 27 = 128 codes Two general types of codes: – 95 are “Graphic” codes (displayable on a console) – 33 are “Control” codes (control features of the console or communications channel) Data Representation Introduction to Information Technologies
- 11. 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 Least 1100 1101 1110 1111 000 001 010 011 NULL DLE 0 SOH DC1 ! 1 STX DC2 " 2 ETX DC3 # 3 EDT DC4 Most significant $ 4 ENQ NAK % 5 ACK SYN & 6 BEL ETB ' 7 BS CAN ( 8 HT EM ) 9 LF SUB * : VT ESC + ; significant bit FF FS , < CR GS = SO RS . > SI US / ? Data Representation 100 @ A B C bit D E F G H I J K L M N O 101 P Q R S T U V W X Y Z [ ] ^ _ 110 ` a b c d e f g h i j k l m n o 111 p q r s t u v w x y z { | } ~ DEL Introduction to Information Technologies
- 12. e.g., ‘a’ = 1100001 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 000 NULL SOH STX ETX EDT ENQ ACK BEL BS HT LF VT FF CR SO SI Data Representation 001 DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US 010 ! " # $ % & ' ( ) * + , . / 011 0 1 2 3 4 5 6 7 8 9 : ; < = > ? 100 @ A B C D E F G H I J K L M N O 101 P Q R S T U V W X Y Z [ ] ^ _ 110 ` a b c d e f g h i j k l m n o 111 p q r s t u v w x y z { | } ~ DEL Introduction to Information Technologies
- 13. 95 Graphic codes 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 000 NULL SOH STX ETX EDT ENQ ACK BEL BS HT LF VT FF CR SO SI Data Representation 001 DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US 010 ! " # $ % & ' ( ) * + , . / 011 0 1 2 3 4 5 6 7 8 9 : ; < = > ? 100 @ A B C D E F G H I J K L M N O 101 P Q R S T U V W X Y Z [ ] ^ _ 110 ` a b c d e f g h i j k l m n o 111 p q r s t u v w x y z { | } ~ DEL Introduction to Information Technologies
- 14. 33 Control codes 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001 1010 1011 1100 1101 1110 1111 000 NULL SOH STX ETX EDT ENQ ACK BEL BS HT LF VT FF CR SO SI Data Representation 001 DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US 010 ! " # $ % & ' ( ) * + , . / 011 0 1 2 3 4 5 6 7 8 9 : ; < = > ? 100 @ A B C D E F G H I J K L M N O 101 P Q R S T U V W X Y Z [ ] ^ _ 110 ` a b c d e f g h i j k l m n o 111 p q r s t u v w x y z { | } ~ DEL Introduction to Information Technologies
- 18. “Hello, world” Example H e l l o , w o r l d = = = = = = = = = = = = Data Representation Binary 01001000 01100101 01101100 01101100 01101111 00101100 00100000 01110111 01100111 01110010 01101100 01100100 = = = = = = = = = = = = Hexadecimal 48 65 6C 6C 6F 2C 20 77 67 72 6C 64 = = = = = = = = = = = = Decimal 72 101 108 108 111 44 32 119 103 114 108 100 Introduction to Information Technologies
- 19. Common Control Codes • • • • • CR LF HT DEL NULL 0D 0A 09 7F 00 carriage return line feed horizontal tab delete null Hexadecimal code Data Representation Introduction to Information Technologies
- 21. Terminology • Learn the names of the special symbols – – – – – – [] {} () @ & ~ Data Representation brackets braces parentheses commercial ‘at’ sign ampersand tilde Introduction to Information Technologies
- 23. Escape Sequences • Extend the capability of the ASCII code set • For controlling terminals and formatting output • Defined by ANSI in documents X3.41-1974 and X3.64-1977 • The escape code is ESC = 1B16 • An escape sequence begins with two codes: ESC [ 1B16 Data Representation 5B16 Introduction to Information Technologies
- 24. Data Representation Introduction to Information Technologies
- 25. Thank you Data Representation Introduction to Information Technologies