Input and output devices in computer-computer world

Input devices : 

Input devices to be useful, a computer system needs to communicate with its external environment(its users).They are also known as peripheral devices.Input device are used to enter data from outside world  into primary storage.An inputs devices is an electronically device that accept  data from outside world and translate them into a form of a computer .

 Following are some of the important input devices which are used in computer :

1. Keyboard  :

 Keyboard devices are the most commonly used input device today they allow data and entry  into a computer system by pressing a set of keys. the most popular keyboard used today is the QWERTY keyboard.

2. Mouse : 

Mouse is the most pointing device it is necessary input device in modern computer because they support GUI(graphical user interface) as their primary user interface. 

3. Trackball : 

Trackball is pointing device similar to a mouse it is a input device as the roller ball placed on the top with buttons. 

4. Joystick : 

Joystick is also a pointing device that work on some principle as trackball. It is a stick having a ball at its both lower and upper ends.A user move the ball by the attached stick with his hand. 

5. Electronic pen : 

It is a pen based point and drown device a user hold the pen in his hand and point with it directly on the screen to select from the displayed menu items or icons.

Another types of electronic pen comes with a spacial pad. The pen is used on the pad as an ink would be used on paper. 

6. Touch screen : 

Touch screen is the most simple and easier way to used of all input device. Touch screen can be attached to computer or to network as terminal.

7. Scan f /Image scanner : 

An image scanner is a input device that translate paper document into an electronic format that can be stored in a computer.   

8. Optical mark reader (OMR) : 

OMR is spacial type of optical scanner used to recognized the type of mark made by pen or pencil. It is used where one out of few alternatives is to be selected. It is used for checking the answer sheet of examination having MCQ.

9. Bar code reader (BCR) : 

Data coded in the form of small lines are known as bar codes. A bar code reader is device used for reading bar code data.

Output device : 

Output device is used to accept data from computer and translate them into a form that is suitable for users. Many output device are available today. They are classified into following categories.

Following are the some important  output devices which are used in computer

1. Monitors : 

Monitor are the most popular output device used today for producing softy copy output on a television like screen.    

2. Printers : 

Printer are the most popular output device used today for producing hard copy output. 

3. Plotters : 

Printer are capable of producing graphics output but many engineering design applications require high quality output on large sheets. Printer are not suitable for meeting this output requirement of such application so a spacial type of output device, called plotter is used for this purpose.    

5. Voice response system : 

A voice response system enable a computer to talk to a user. A voice response system as an audio responsive device that produced audio output. The nature of output is softy copy and temporary.