The structural foundation for an operating system
R. C. Varney · The Computer Journal · 1973
Operating systems have come into wide use within the last decade; many of today's systems have evolved into large, hard-to-understand complexes from small, workable monitoring systems. The object of this paper is to present the basic concepts of a well-structured environment which can support a highly complex operating system, but which at the same time can remain generally comprehensible, by virtue of its structure and the basic components of that structure. The paper begins with the basic design criteria and goals. It then presents the idea of a well-defined tree structure using the concepts of local-level knowledge (which delimits the scope of the processes at each node of the tree), modularity (which separates the system into workable parts), and functionality (which demands that each level of abstraction be well-specified). Two concepts, namely the process selector tree and recordability tree, are discussed as natural extensions of a tree structured system.