Supporting system maintenance with automatic decomposition schemes

Automatic decomposition schemes at the procedural implementation level can be useful in all three phases of system maintenance, namely comprehension, testing, and debugging. A software system-comprising multiple functional, data storage, and control modules-can be decomposed along the three dimensions of partition, abstraction, and projection. Dependence relations have been used for automatic program decompositions at a single-module level. Dependence relations, defined for multiple module data-driven systems, are used in generating system-level projections. This is accomplished by visualizing a multimodule system as a structured program implemented in a system description language. The data storage modules are represented as variables, the functional modules (implemented in a procedural language) are represented as generalized assignment statements, and control modules are represented as control flow primitives