A Larch Specification of the Library Problem

A claim made by many in the formal specification community is that forcing precision in the early stages of program development can greatly clarify the understanding of a client's problem requirements. We help justify this claim via an example by first walking through a Larch specification of Kemmerer's library problem and then discussing the questions that arose in our process of formalization. Following this process helped reveal mistakes, premature design decisions, ambiguities, and incompletenesses in the informal requirements. We also discuss how Larch's two. tiered specification method influenced our modificationsto and extrapolations from the requirements.