A method is disclosed of maintaining data. The method includes the steps of providing a plurality of data storage mediums, each comprising a parity bit that provides an indication of the parity of the data in each respective data storage medium, at least one of the data storage mediums providing an exclusive OR function of a parity output bit of the at least one of the plurality of data storage mediums; encoding data provided by the exclusive OR functionality of the parity output bit to provide encoded data; time stamping the encoded data with a time stamp circuit that is coupled to the encoded data to provide time stamped encoded data; and providing the time stamped encoded data to a time-retrieval data storage medium.