A Level Ict Revision Notes

Data types * text * still and moving images * numbers * sound
Input devices
Keyboards
· Most common type of keyboards is the qwerty keyboard
· Another type of keyboard is a concept keyboard. They can be specially designed so that people with restricted vision can use them to interact with a computer. Most commonly programmed to perform common commands with one key.
Point and click devices
· Include mouse, tracker balls, touch sensitive pad, joystick, light pens, touch screens and graphic tablets
· A mouse translates movement on a desktop into digital information. This information is converted into movement of the cursor on the screen. Am mouse will also have buttons which can be clicked to help the user select what functions they want to use.
· A tracker ball is essentially an upside down mouse.
· Instead of moving a mouse on a surface, the ball is rotated. It achieves the same results as a mouse, just with less space.
· Touch sensitive pads are most commonly found on laptops a stylus or the users finger are touched gently on the ad and as it is moved the curser on the screen moves.
· Joysticks are commonly used to interact with computer games, although they are also used in other circumstances (hospital scanners) like a tracker ball movement of the joystick is reflected by the movement on the screen
· A Light pen uses specialist software and is used in specialist situations. The light pen works by being touched on the screen. As the pen is moved on the screen the curser moves.
· Touch screens are a special type of screen that is sensitive to touch. Selections can be made by touching the screen. They are most commonly used in banks, shops and building societies. No training is necessary to use the touch screen.
· A graphics tablet allows the user to create designs directly onto the screen. A special stylus is connected to the computer via the