Managing Change in Information Systems : technological challenges

Information systems and other computer-based systems must continuously undergo change in order to reflect change in their environments. The present technology used to implement such systems, including models, methods, tools and languages, does not have an inherent understanding of the nature of evolution. The rigidity of existing systems is a hindrance for user requested enhancements.Propagating changes correctly is a particular problem. It is common to find that necessary changes consequent on some other change have not been made, so that the system is inconsistent and will eventually fail to operate correctly. The paper discusses tools for system maintenance and focuses on the issue of automation. A tool that automatically generates and maintains all the information it needs is presented. To provide more information about the form and extent of the evolution in real-world systems, the same tool was instructed to collect change measurements. Information about the evolution of a large health management system was recorded over a period of 18 months. Methods for and problems of automatic change measurements collection are discussed

Managing change in persistent object systems

Persistent object systems are highly-valued technology because they o er an e ec- tive foundation for building very long-lived persistent application systems (PAS). The technology becomes more e ective as it o ers a more consistently integrated computational context. For it to be feasible to design and construct a PAS it must be possible to in- crementally add program and data to the existing collection. For a PAS to endure it must o er exibility: a capacity to evolve and change. This paper examines the capacity of persistent object systems to accommodate incremental construction and change. Established store based technologies can support incremental construction but methodologies are needed to deploy them e ectively. Evolving data description is one motivation for inheritance but inheritance alone is not enough to support change management. The case for supporting incremental change is very persuasive. The challenge is to provide technologies that will facilitate it and methodologies that will organise it. This paper identi es change absorbers as a means of describing how changes should propagate. It is argued that if we systematically develop an adequate reper- toire of change absorbers then they will facilitate much better quality change man- agement

Software constraint models : a means to improve maintainability and consistency

As application systems live longer and grow in size and complexity, there is an ever increasing need for methodologies, models and tools that can aid software builders in developing maintainable, correct and consistent systems. Imposing constraints, representing architectures, conventions, guidelines, etc., on the software is one step in that direction. One may distinguish between constraints within programs, constraints between programs, and constraints between programs and secondary storage. A coherent set of constraints are collected in a software constraint model. Automatic verification tools are crucial to the usefulness of such models. The paper describes a constraint model and a corresponding verification tool that have been developed in a persistent programming environment

Software Constraint Models - A Means to Improve Maintainability and Consistency

As application systems live longer and grow in size and complexity, there is an ever increasing need for methodologies, models and tools that can aid software builders in developing maintainable, correct and consistent systems. Imposing constraints, representing architectures, conventions, guidelines, etc., on the software is one step in that direction. One may distinguish between constraints within programs, constraints between programs, and constraints between programs and secondary storage. A coherent set of constraints are collected in a software constraint model. Automatic verification tools are crucial to the usefulness of such models. The paper describes a constraint model and a corresponding verification tool that have been developed in a persistent programming environment. Keywords: programming environments, maintenance, consistency, software constraints 1 Introduction Large, long-lived and data-intensive application systems that satisfy a complete area of information-processi..

Managing Change in Information Systems: Technological Challenges

: Information systems and other computer-based systems must continuously undergo change in order to reflect change in their environments. The present technology used to implement such systems, including models, methods, tools and languages, does not have an inherent understanding of the nature of evolution. The rigidity of existing systems is a hindrance for user requested enhancements. Propagating changes correctly is a particular problem. It is common to find that necessary changes consequent on some other change have not been made, so that the system is inconsistent and will eventually fail to operate correctly. The paper discusses tools for system maintenance and focuses on the issue of automation. A tool that automatically generates and maintains all the information it needs is presented. To provide more information about the form and extent of the evolution in real-world systems, the same tool was instructed to collect change measurements. Information about the evolution of a lar..

Thesaurus-Based Software Environments

Introduction Software environments support the process of constructing and maintaining application systems. This paper describes the idea of a thesaurus 1 as a viable foundation for software environments. A thesaurus contains information about the names and identifiers in all the software written in all the languages of an application. Information about extensional data in a database or persistent store is also included. The comprehensiveness of the thesaurus is in contrast to most commercially available tools which focus either on the source code only (source code analysers) or on database-specific information (data dictionaries). A few data dictionary tools also include source code information, but relationships between names and identifiers in the software written in the various languages are not recorded automatically. All the contents of the thesaurus are automatically maintained. The whole application system is anal