1. Introduction of Computer
1.3 Components of Computer System?
1.3.1 Key Board, Mouse, VDU
Keyboard is an input device. Computer keyboard is an electromechanical component designed to create special standardized electronic codes when a key is pressed. Keyboards come in a variety of sizes and shapes having a number of features in common: 1. Standard TypeWriter keys 2. Function keys 3. Special purpose keys 4. Cursor Movement keys 5. Numeric keys
The mouse is also an input device that is much in use nowadays in graphics as well as when working with a GUI(Graphic User Interface). About the size of an audiocassette, it slides on a rubber ball and has two or more buttons on the top. When a mouse is slid across a flat surface, the screen cursor also moves in the direction of the movement of the mouse. With a click of the button, the system can be notified of the selected position.
Visual Display Unit is the most popular I/O device used nowadays for interactive processing. A keyboard is used to enter data into a processor and a Video Display Unit, called Monitor, is used to display the keyed data and to receive processed information and messages from the computer. Visual Display Unit/Terminal.
VDTs are classified as:
1.Dumb terminals: These are simple devices that immediately transmit each keyed data character to the processor.
2.Intelligent terminals: These combine VDT hardware with built-in microprocessors. They can process small jobs without the need to interact with the main computer