A data processing system is provided with a memory controller (130) converting memory addresses (170) into selecting signals (120) for a memory device (100). The mapping between memory addresses and selecting signals is provided by mapping logic (140) within the memory device. The configuration of the mapping logic, also known as a mapping scheme, is defined by data stored in mapping specifying data storage (150), which may be altered by operating system software or application software (160) running on the system. Altering this configuration may be as a result of signals received from a monitoring unit (135) which monitors the efficiency with which the current mapping scheme is accessing data stored in the memory device. More than one mapping scheme may be used within a single memory device.