Computer-readable medium storing a data structure for supporting persistant storage of a set of data, the data structure including: (a) at least an oldest version of the set of data in a first memory area the first memory area including at least one first tag for uniquely identifying the oldest version, and (b) at least a most recently updated version of the set of data in a second, distinct memory area, the second memory area including at least one second tag for uniquely identifying the most recently updated version. The invention also relates to a computer arrangement including a processor and such a computer-readable medium, as well as to a method of updating sets of data having such tagged-data structures.