Patent ID: 7577950

Claim:
A method of updating a navigation system by copying updated data to a rewritable storage of the navigation system, comprising the following steps of: installing an optical disk in an optical disk driver where the optical disk is specially made in such a way that content data becomes unreadable after passage of a predetermined time length; reading the data from the optical disk and copying the data in the rewritable storage of the navigation system; prohibiting from taking out of the optical disk from the optical disk driver by keeping closing the optical disk driver; starting a timer to monitor a time passage with respect to the predetermined time length; periodically checking readability of the data from the optical disk to determine whether the optical disk has undergone a change such that the data in the optical disk cannot be read any longer; and enabling to open the optical disk driver for removal of the optical disk therefrom after receiving an end signal from the timer indicating an end of the predetermined time length.