11.1: Basic Reliability Mechanisms (a)
In studying classes, we have — temporarily — lost sight of this semantic aspect of the ADT concept. We will need to bring it back into the method if we want our software to be not just flexible and reusable, but also correct and robust.
The effort to limit inter-module communication to the strict minimum resulted in the prohibition of such common reliability risks as global variables, and in the definition of restricted communication mechanisms, the client and inheritance relations.