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Input and Output Devices

Input and Output Devices

An input device is used to feed data and instructions into the computer. In the absence of an input device, a computer would have only been a display device. Correspondingly, any device that outputs/gives information from a computer is called an output device. Refer to Figure 1.19 which shows some basic I/O devices that are generally connected with our computer system.

Input device

Some of the input devices that are widely used by computer users to feed data or instruction to the computer are keyboard, mouse, trackball, joystick, stylus, touch screen, barcode reader, optical character recognition (OCR) device, optical mark recognition (OMR), MICR, web and digital cameras, etc.

Output device

We can classify the output devices in two categories.


Soft copy output devices are those output devices which produce an electronic version of an output. For example, a file which is stored on hard disk, CD, pen drive, etc. and is displayed on the computer screen (monitor). Features of a soft copy output include:

  • The output can be viewed only when the computer is switched On.
  • The user can easily edit the soft copy output.
  • Soft copy cannot be used by people who do not have a computer.
  • Searching data in a soft e copy is easy and fast. 
  • Electronic distribution of a soft copy is cheaper. It can be done easily and quickly.


Hard copy output devices are those output devices which produce a physical form of ou the content of a file printed on a paper (using printer and plotters) is a form of hard copy a hard copy output include:


  • Computer is not needed to see the output.
  • Editing the hard copy is difficult.
  • Hard copy output can be easily distributed to people who do not have a computer.
  • Searching data in a hard copy is a tiring and difficult job. 
  • Distribution of a hard copy is not only costly but also slower.

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