Input and output devices of a computer

The devices that help the user to communicate with the computer are input devices. Once the data is fed into the computer, it works on the data, processes it and provides the results to the user. The devices that help the user to get the output from the computer are output devices.

Input devices
Input devices are those devices that are used to feed data and programs into a computer.

• Keyboard: the keyboard of a computer resembles a typewriter with a few additional keys to handle various functions. A computer keyboard has three categories of keys:
  Alphanumeric keys: Alphabets, numbers, characters.
  Special keys: enter, backspace, Del, esc, Ctrl, alt.
  Function keys: (f1 to f 12) for selected operations.
• Mouse: the mouse is one of the most popular input devices. This device helps you to manipulate a pointer or an arrow on the screen. The pointer moves according to the movement of the mouse on a flat surface.
• Light pen: helps in identifying bar codes.
• Scanner: scans documents and photos and transmits them to the computer.
• Microphone: helps to record sounds to the computer and extensively used to talk through the internet.
• Web camera: Also called webcam is a small low resolution digital video camera. Web accessible cameras upload images to a web server.
• Joystick: used mainly to play games.

Output devices
These are the devices that are useful in receiving information or processed data from the computer. Some of the commonly used output devices are

• Visual display unit: the unit that resembles a TV screen and commonly referred to as ‘Monitor’. This unit informs us about the activities performed by the computer.
• Printers: printers are the primary output device used to prepare permanent documents. The printers that are widely used are Dot Matrix, LaserJet and Inkjet.
• Plotters: plotters are used for high quality diagrams. A pen is mounted on an arm, which moves along the paper with the help of motors. This is used in making high-resolution sketches and maps.
• Speakers: helps in listening to music and soundtracks of applications.

Input/output devices
The information in the disks is read by a disk drive. It is this same drive, which helps in writing or recording information to the disks (hard disk, floppy disk, CD R/RW). Hence, the disk drive is called an input/output device.