This paper describes an approach to software specification development with interpretation as applied to an information storage and retrieval system. Machine execution of software specifications is possible with both partial and complete specifications. A partial specification is interpreted using abstract execution. The Descartes specification language is utilized to describe a functional aspect of an existing information storage and retrieval system, namely, the MADAM (Multics Approach to Data Access and Management) system at the University of Southwestern Louisiana. Brief descriptions of both the Descartes language and the MADAM system precede the example specification. The paper concludes with a discussion of the expected results that this methodology could have on the pragmatic development and evolution of information systems.