The modular structure of complex systems

摘要

This paper discusses the organization of software that is inherently complex because there are very many arbitrary details that must be precisely right for the software to be correct. We show how the software design technique known as information hiding or abstraction can be supplemented by a hierarchically-structured document, which we call a module guide. The guide is intended to allow both designers and maintainers to identify easily the parts of the software that they must understand without reading irrelevant details about other parts of the software. The paper includes an extract from a software module guide to illustrate our proposals.