Fairness and conspiracy concepts in concurrent systems

Abstract

Many different fairness notions are available in literature. One should choose the proper definition that match with the system under consideration. In this paper we consider two known fairness definitions, viz., weak fairness and strong fairness. It is argued that these concepts are suitable for determining the degree of fairness of a given system. For only starvation freedom we require a minimum degree of fairness which we call least fairness. This idea is illustrated using two practical examples. Conspiracy is another very important issue in concurrent system. We have defined conspiracy in connection with all the fairness notions. Conspiracy resistant implementation is illustrated using a starvation free solution to dining philosophers problem. Dijkstra's weakest precondition calculus is used as the analytical tool.