In one embodiment, an advertisement is matched to subject matter in a portion of rich media content, such as a digital video, Flash\u2122 animation, etc. Two turning pieces, each of which has a first guiding slot, a second guiding slot and a rack. A reproduced image captured before the currently captured image is displayed on the left thereof. Therefore, when data is to be deleted from the second level cache memory, a determination is made whether the data has been modified by the processor.