input and output and processing
The difference between input and output:
The difference between output and input devices is that an output device displays information that is conveyed to the user. This function is performed by the output devices.
Without external data a computer can do almost nothing. The role of the input device is to 'input' data into the computer.
speakers are outputters because they give out sound.
a mouse is an input device. It selects what you want it to by moving it around and clicking it.
display device is an output device because it lets you see what's being displayed on the screen.