A physical docking interface facilitates co-processing with an extended processing module of an extended computer unit in a physical docked mode, when the handheld computing unit is coupled to the extended computer unit via the physical docking interface. A quasi docking interface facilitates co-processing with the extended processing module in a quasi docked mode when the handheld computing unit is coupled to the extended computer unit via the quasi docking interface. A graphical user interface presents a selectable quasi docking interface graphic for display to a user and responds to a user selection of the selectable quasi docking interface graphic by generating a quasi docking command. The quasi docking interface couples the handheld computing unit to the extended computing unit in response to the quasi docking command.