Rules to govern change in JSP-based systems

The Jackson structured program (JSP) methodology as widely practiced does not directly address problems of software maintenance, but rather implies restrictions on modifications of finished program designs. An investigation is made which defines limits of permissible changes to data structures and process structures, and these changes are incorporated into rules that will govern and therefore control change. The investigation into these permissible changes centers on structural changes, as nonstructural changes do not have the same potentially severe effects. The rules lend themselves to both computerized and manually produced program specifications based on the Jackson method