A hard disk system for storing user data for an information device. The hard disk system includes a non-volatile, IC based memory such as e.g., a memory utilizing MRAM, to non volatilely store system data for the hard disk. Examples of system data include a master list, a list of unused sectors, and a list of defective sectors. In some examples, the master list includes the physical location on a hard disk where data of a file is stored. The non-volatile memory is operably coupled to a data storage system processor and may be implemented on a circuit board with the data storage system processor.