A method is provided for storing data on memory devices comprising a plurality of erasable units, wherein the size of said erasable units is an integer multiple of a first integer value, comprising providing a data structure comprising a plurality of data units each including a data unit header, wherein the size of said data units is equal to said first integer value, a plurality of data items and corresponding data item headers within each data unit, associating at least one data unit to each erasable unit, storing said data in said data items and storing data item status information in the corresponding data item headers, and storing data unit status information in said data unit headers.