Procedural encapsulation: A linguistic protection technique

Abstract

System reliability is an important aspect of operating system construction. Because of this, a number of researchers have proposed design methodologies [e. g., 1, 2, 3] which are intended to produce more reliable software. Although the methodologies differ, there seem to be some important properties that they have in common. One property is the decomposition of the system into components or modules which make as few assumptions as possible about the other components. We will call this the “minimal assumptions” property. Minimizing the assumptions one component makes about another component means that subsequent maintenance and extensions can be done with a smaller probability of introducing errors. A programmer is less likely to overlook critical, obscure interconnections if such interconnections are severely restricted.