1. A data storage system comprising: a memory array including a plurality of memory devices programmable in greater than two states; and a read/write control module, executed by a processor, to overwrite data in the memory array without violating a constraint during the overwrite process, and to determine if a target entry, which is a data value to be written to a selected memory device in the memory array, is less than a corresponding initial entry, which is a data value currently stored in the selected memory device in the memory array, and based on the determination, the read/write control module is to overwrite data in the selected memory device.