In order to facilitate the work to the user by the user does not need to know the hardware can run easily, so they must have the w function to communicate with the user in a way that is easy to use.
To facilitate the work of the users, by the users do not need to know the hardware works. It can run easily, so it must have served w user interface. In a manner that is easy to use.
To facilitate work to the user by the users don't need to know the function of the hardware, it can work easily. It has w responsible for communicating with the user. In a simple manner to use.