The present invention has an object to provide a rotating polishing tool with high durability that can finish a polished surface with desired surface roughness. The differential datapath can translate between the differential signals and card-specific signals that control readwrite operations to the memory array of the flash memory card. The interface circuit 13 is provided to interface the color component signals with a digital signal processor 14. The AD converter converts the analog signal to a digital signal over conversion cycles using an adaptable bit number so that on at least a portion of the conversion cycles an adapted number of bits spanning a portion of the full scale range less than the total number of bits is used by the AD converter to convert the analog signal. A locking protocol for the metadata ensures concurrency control and triggers dependency tracking.