Computer being a versatile machine can process different types of data. so to work with these data types we need different type of devices which can help us to enter such data types in the computer and to receive their outputs as well in this chapter we will cover many such devices like keyboard, mouse, joystick, light pen, printer, speaker, etc. That can be used with the computer. What is computer?Children you know that computer is a data processing machine and it needs user’s instructions to perform any job. After processing the raw facts (called data), it produces useful information for the user. But how do you give data and instructions to the computer and how it can return the useful information to you.To do all these, different types of input and output devices can be connected with the computer.Input DevicesThe devices which are used to give data and instructions to the computer are called Input Devices. Various types of input devices can be used with the computer depending upon the type of data you want to enter in the computer, e.g., keyboard, mouse, joystick, light pen, etc.Output DevicesThe devices which are used to display the results or information are called Output Devices. You can view the output on the monitor or you can print it on a paper using a printer. Monitor and the printer are the commonly used output devices.