INPUT OUTPUT ORGANISATION Chapter 11 Peripheral Devices The

INPUT OUTPUT ORGANISATION Chapter 11

Peripheral Devices • The input output subsystem of a computer system provides communication between central system and outside environment. • Input Output devices attached to the computer are called peripherals. examples: keyboard, monitor, printer etc.

Monitors available these days: • CRT (Cathode Ray Tube) • LCD(Liquid Crystal Display) • LED • TFT Different types of printers : Inkjet printers Laser printers etc

ASCII Alphanumeric Characters • A character encoding standard for electronic communication. • Abbreviated from American Standard Code for Information Interchange. • Communication between people and computer involves use of alphanumeric characters. • The standard binary code for alphanumeric characters is ASCII

It uses 7 bits to code 128 characters. • 94 of the encoded characters are printable: these include the digits 0 to 9, lowercase letters a to z, uppercase letters A to Z, and 32 special characters (eg %, *, $ etc) In addition, there are 34 non-printable characters :

Eg. STX(Start of Text), SP(Space)etc. • There are 3 types of control characters: 1. Format Effectors: Used to Control the layout of printing Eg: backspace(BS), horizontal tab(HT) etc. 2. Information Separators: Used to separate data into divisions like paragraphs and pages. eg record separator(RS) and File Separator(FS)

3. Common Control Characters: • Useful during transmission of text between remote terminals. Eg: STX(Start of Text), ETX(End of text)