Data structure that is associated with an hierarchical file system of a computational system. The hierarchical file system includes a set of files arranged in a directory structure including a set of directories. The data structure includes a data store with a set of reference data objects (topics) and a set of coupling data elements. The set of coupling data elements includes at least: one coupling data element for coupling a first item selected from either the set of reference data objects or the set of files or the set of directories with a second item from either the set of reference data objects or the set of files or the set of directories.