Described is a system and system by which application programs provide data to auxiliary display device (that is associated with a main computer system) for display, including at times when the main computer system is powered down. The cache maintains the user data in association with structured navigational information, to allow navigation within the data via the structure. When online, the main computer system prepares the data cache from program data in combination with navigational information, and transfers the cache to an offline medium such as auxiliary storage in firmware. The cache may be arranged as a tree structure, such that navigation commands result in output according to data in the tree. Other events such as time-based events can change the auxiliary device output.