Patent ID: 7634688

Claim:
A method of automatically saving data upon interruption of power from a primary power supply in a data processing device comprising a cache controller, a non-volatile memory device for storing data and retaining the stored data when the primary power supply is deactivated, and a volatile memory device for caching data from the non-volatile memory device when the primary power supply is activated, comprising: reading sectors of data from the non-volatile memory device and writing the data to a corresponding sector of the volatile memory device; modifying at least one sector of data stored in the volatile memory device; storing a directory list in the cache controller, the directory list associating the at least one sector of data stored in the volatile memory device with a corresponding location in the non-volatile memory device, the directory list further designating the at least one sector of data thus modified; detecting a power interruption in the primary power supply, enabling a secondary power supply upon detection of the power interruption in the primary power supply; and writing the at least one sector of data thus modified from the volatile memory device and the directory list from the cache controller to the non-volatile memory device while the secondary power supply is enabled and the primary power supply is interrupted.