- input-output and storage
- Its a peace of hardware that is used to store data into a computer.
- Smart phones are a input device.
- An input device sends information to a computer system for processing
- A computer is a machine that can be programmed to accept data
- output device reproduces or displays the results of that processing.
- Speakers and headphones are output devices that can play sound
- In equation form, an x usually represents the input quantity