Abstract: Provided is a watchdog system including: a software area including a bootloader area and an application area, and a shared memory area storing the last watchdog refresh timing; and an external watchdog module refreshing a watchdog when a transmitted refresh request timing corresponds to window open time in response to a refresh request transmitted from either the bootloader area or the application area and based on the last watchdog refresh timing transmitted from the shared memory area and the transmitted refresh request timing.

Abstract: Provided is a watchdog system including: a software area including a bootloader area and an application area, and a shared memory area storing the last watchdog refresh timing; and an external watchdog module refreshing a watchdog when a transmitted refresh request timing corresponds to window open time in response to a refresh request transmitted from either the bootloader area or the application area and based on the last watchdog refresh timing transmitted from the shared memory area and the transmitted refresh request timing.

Abstract: A method for controlling layer jump in an optical disc drive is provided. In one embodiment of the present invention, upon request of layer jump, a circumferential position of a rotating disc can be compared with predetermined circumferential position stored in a memory based on a signal generated at a spindle motor and layer jump operation can be performed at the predetermined circumferential position. The predetermined circumferential position can correspond to a position where displacement of a disc in up and down direction while the disc makes one rotation becomes largest and/or smallest. The predetermined circumferential position can be detected when an optical disc inserted is recognized to have two or more recording layers based on a driving signal applied to a focusing actuator at an outer circumference of the disc while a focusing servo is turned on.