OBJECT-ORIENTED DESIGN FOR DISTRIBUTED SYSTEMS - THE OSI DIRECTORY EXAMPLE

For an object-oriented design methodology to be effective, it is important to provide methods and tools for validating the design specification before going into the implementation phase. The paper proposes a design methodology and a related object-oriented specification language which allows the validation of specifications through simulated execution, or through automatic exhaustive simulation for a certain subset of the language. The paper also discusses the relation of this design methodology and language to other design methodologies which are in wide use, such as the entity-relationship model for databases, the ASN.1 notation used for Open Systems Interconnection (OSI) communication protocols, as well as methodologies used in the standardization committees for the elaboration and description of various kinds of distributed systems standards. It is shown how these different approaches can be integrated into a single methodology and language, using the OSI Directory System as an example, which is explained in certain detail.