What It Means for a Concurrent Program to Satisfy a Specification: Why No One Has Specified Priority

Abstract

The formal correspondence between an implementation and its specification is examined. It is shown that existing specifications that claim to describe priority are either vacuous or else too restrictive to be implemented in some reasonable situations. This is illustrated with a precisely formulated problem of specifying a first-come-first-served mutual exclusion algorithm, which it is claimed cannot be solved by existing methods.