The importance of static structures in software construction

The static structure is the physical organization of a system´s functional modules in terms of their structural relations. It is the packaging of the dynamic structure into textually self-contained modules, taking into consideration the construction strategy and how much of module´s internal part should be visible to other modules. Hierarchical modular diagrams (HMD), a module-interface-oriented graphics language that develops can specify the structural relations among modules and map design concepts into a hierarchy of program components independently of the implementation language, is described. The application of HMD to manage a real-time system in a library of separately compiled Ada units is described. It is shown that by using HMD in conjunction with modern software engineering languages like Ada, the static structure can be built earlier in the design process. This lets designers evaluate safety-critical issues as well as reusability concerns long before they make safety checks and implementation decisions. More important, engineers can analyze the effect of approaches to incremental construction before committing additional resources.<>