A core component is disclosed which includes a processing module and a touch screen. The core component may operate by itself in a first mode to perform functions similar to that of a conventional personal digital assistant (PDA). In particular, the touch screen may both provide visual output and receive input from a user's finger when the core component operates in the first mode. When the core component is connected to another component including a display screen, the core component may operate in a second mode in which input received through the touch screen is provided to the other component. For example, the movement of a user's finger may control the position of a cursor displayed on a screen of the other component so that the core component exhibits the behavior of a trackpad when operating in the second mode.