In designing and building persistent object systems we are attempting to regularise the activities on data that are traditional in programming languages, operating systems, database management systems and file systems. We hypothesise that regularity and simplicity may be achieved by regarding the exercise as one of designing a language powerful enough to allow for all our programming needs and using some principles in the design of the language to achieve this regularity and simplicity. In this paper we investigate the nature of binding mechanisms showing how some form of dynamic binding is necessary for persistence. The binding mechanisms of Ada, which has a traditional file based view of persistence, and of Napier, which has an object based view, are used as illustrations. 1. Introduction In traditional programming languages, database management systems, file systems and operating systems there are a number of, often conflicting, binding mechanisms for composing sub-systems, program...