Abstract: During power-on of a navigation device, a control circuit executes an investigation process for determining whether backup data stored in a memory should be erased. In this investigation process, the control circuit confirms that a first determination or a second determination is affirmed, based on a large volume storage medium being presently attached. The first determination is whether the attached medium is substituted during power-off of the navigation device, while the second is whether information stored in the attached medium is updated during the power-off. Affirming of the first determination or the second determination is judged from whether a use restriction is applied to the attached medium, whether a serial number of the attached medium accords with a serial number stored in the navigation device, and whether a password stored in the navigation device can access to the attached medium.

Abstract: A navigation apparatus, which can reduce time to restore a display condition as much as possible, even when it becomes necessary to restart during executing software, by omitting several initializing processes when the apparatus restarts. In a navigation apparatus, at a time of startup, a display controller is initialized and an initial picture is displayed, so that other initializing process is performed. After that, a present position is displayed and normal navigation process is performed. When a control is complicated as a result of executing plural programs at same time, improper exception occurs and then restarts. In this time, as a pre-process, a map display picture of the present position is stored in an external memory. At a restart process, the display controller firstly displays the map display regarding the present position, and the restart process is performed under this condition so as to restore a normal condition.