A portable computer is provided with a combination trackball/mouse pointing device for controlling cursor movement on the computer screen. In one positional mode thereof, the device is removably inserted into a recess in the computer base housing and serves as an integrated trackball. In another positional...http://www.google.com/patents/US6392634?utm_source=gb-gplus-sharePatent US6392634 - Portable computer having reversible trackball/mouse device
