Modularity in the Design and Standardisation of Open Systems

Abstract Some practical suggestions are made as to how data abstraction may be used to provide a modular framework for the design of open systems and their means of interconnection. This framework is technically advantageous in clarifying the interfaces between the parts of a large design, and would also help in planning and coordinating the work of standards committees. A reference model for languages applicable to local system function is compared with the reference model for open systems interconnection (OSI), and a clarification is suggested which would make the models compatible. Two major functional requirements are proposed for the application layer of the OSI model, namely the ability to transmit arbitrary operations to be performed on remote objects, and the option to specify whether objects or merely references to them should be transmitted.