pointing devices

Pointing Devices are direct entry input devices. They allow users to control the pointer and the insertion point on the screen. Examples of pointing devices are mouse, trackball, touch pad, pointing stick, joystick, touch screen, light pen and graphics tablets.
A mouse is a computer device, which has a ball sealed at the bottom. It is attached with a cable to the system unit. When rolled on the flat surface, the movement of the ball will generate electrical circuits, which are then sent to the computer. The movement of the mouse controls the insertion point and pointer on the screen. Moving the mouse allows user to positions the pointer or cursor an indicator on the screen that shows where the next interaction with the computer will take place. When the mouse is moved to the left, the pointer will move to the left, when the users move it to the right, the pointer on the screen will move to the right. Many users turn to the mouse as a quick substitute for some functions of the keyboard. There are various types of mouse operations such as point, click, double-click, right click, drag and so on. A cordless mouse users infrared remote transmission to communicate with the computer. Normally there is an IrDA (Infrared Data Association) port on the system unit to receive the signals sent by cordless mouse.
A trackball is a pointing input device with a ball on the top. It is a type of upside-down mouse. The ball is manipulated by palm or finger. As with a mouse, movement of the ball causes electrical circuits, which are sent to the computer. The corresponding movement of the cursor on the screen. Trackballs are often built into laptop computers. Trackball can replace a mouse if the user cannot find a flat surface for an ordinary mouse to roll on. It is very useful to operate if there is a limited desk space.
A touch pad is a small sensitive area, normally built on the laptop computer. It is sensitive to pressure and motion. Once there is pressure or motion, signals