A software maintenance method based on the software configuration management discipline

Software maintenance has until recently been the neglected phase in the software engineering process, despite the fact that maintenance of existing software systems may account for over half of all efforts expended by a software organization. Research into software maintenance, compared to other phases of the software engineering process is rare. Moreover, it is widely accepted that current software maintenance methods and techniques are unable to cope with the complexity inherent in maintaining software systems. This thesis is concerned with the development of a method, named Configuration Management Formalization for Maintenance (COMFORM), designed for the maintenance of existing software systems. COMFORM provides guidelines and procedures for carrying out a variety of activities performed during software maintenance. It accommodates a change control framework, around which the Software Configuration Management discipline is applied. Redocumentation is another problem tackled by COMFORM, which gathers together the documentation necessary to improve the maintainability and quality of existing software systems. This is achieved by the use of forms representing the output of each phase of a proposed software maintenance model. The information obtained by filling in forms is formalized according to a data model, which provides a common basis for the representation of the method's functionality. Finally, a prototype of COMFORM has been implemented, so that the procedures and guidelines set up by the method can be enforced and followed by its users

End-user documentation

The first and most basic problem with documentation is that the consumer of software applications does not want to use the documentation included with a software product for one or more reasons. Studies, and papers, have been done on the effect that documentation has on a user's satisfaction with a software application; its ease of use, how quickly a user can learn to use the application, and on how documentation should be standardized. The premise of this thesis is that an improvement to the software maintenance processes can be achieved by limiting maintenance requests to "actual” problems with software, versus "perceived" problems caused by inadequate end-user documentation. After analyzing the literature within the computer science communities on the software maintenance process, and the literature within the educational and psychological communities on learning, retention, and the effect of software documentation on the end-user, a modification to the Foster Model was conceived. This model incorporates the concept of an Interactive Documentation Program (IDP), which allows for the end-user to utilize end-user directed and task-based documentation to improve their skills with the operation of commercially available off-the-shelf "office application" software as well as in-house developed software of a similar nature. To ascertain the viability of this concept, a world-wide survey of end-users is concerning their needs, desires, expectations, and complaints concerning end-user documentation was conducted. Combining the statistical results of the analysis of this survey with the concept of the IDP resulted in a new visuaUy-based and task oriented documentation paradigm called hypervideo

Early detection of ripple propagation in evolving software systems

Ripple effect analysis is the analysis of the consequential knock on effects of a change to a software system. In the first part of this study, ripple effect analysis methods are classified into several categories based on the types of information the methods analyse and produce. A comparative and analytical study of methods from these categories was performed in an attempt to assist maintainers in the selection of ripple effect analysis methods for use in different phases of the software maintenance process. It was observed that existing methods are most usable in the later stages of the software maintenance process and not at an early stage when strategic decisions concerning project scheduling are made. The second part of the work, addresses itself to the problem of tracing the ripple effect of a change, at a stage earlier in the maintenance process than existing ripple effect analysis methods allow. Particular emphasis is placed upon the development of ripple effect analysis methods for analysing system documentation. The ripple effect analysis methods described in this thesis involve manipulating a novel graph theory model called a Ripple Propagation Graph. The model is based on the thematic structure of documentation, previous release information and expert judgement concerning potential ripple effects. In the third part of the study the Ripple Propagation Graph model and the analysis methods are applied and evaluated, using examples of documentation structure and a major case study

Inverse software configuration management

Software systems are playing an increasingly important role in almost every aspect of today’s society such that they impact on our businesses, industry, leisure, health and safety. Many of these systems are extremely large and complex and depend upon the correct interaction of many hundreds or even thousands of heterogeneous components. Commensurate with this increased reliance on software is the need for high quality products that meet customer expectations, perform reliably and which can be cost-effectively and safely maintained. Techniques such as software configuration management have proved to be invaluable during the development process to ensure that this is the case. However, there are a very large number of legacy systems which were not developed under controlled conditions, but which still, need to be maintained due to the heavy investment incorporated within them. Such systems are characterised by extremely high program comprehension overheads and the probability that new errors will be introduced during the maintenance process often with serious consequences. To address the issues concerning maintenance of legacy systems this thesis has defined and developed a new process and associated maintenance model, Inverse Software Configuration Management (ISCM). This model centres on a layered approach to the program comprehension process through the definition of a number of software configuration abstractions. This information together with the set of rules for reclaiming the information is stored within an Extensible System Information Base (ESIB) via, die definition of a Programming-in-the- Environment (PITE) language, the Inverse Configuration Description Language (ICDL). In order to assist the application of the ISCM process across a wide range of software applications and system architectures, die PISCES (Proforma Identification Scheme for Configurations of Existing Systems) method has been developed as a series of defined procedures and guidelines. To underpin the method and to offer a user-friendly interface to the process a series of templates, the Proforma Increasing Complexity Series (PICS) has been developed. To enable the useful employment of these techniques on large-scale systems, the subject of automation has been addressed through the development of a flexible meta-CASE environment, the PISCES M4 (MultiMedia Maintenance Manager) system. Of particular interest within this environment is the provision of a multimedia user interface (MUI) to die maintenance process. As a means of evaluating the PISCES method and to provide feedback into die ISCM process a number of practical applications have been modelled. In summary, this research has considered a number of concepts some of which are innovative in themselves, others of which are used in an innovative manner. In combination these concepts may be considered to considerably advance the knowledge and understanding of die comprehension process during the maintenance of legacy software systems. A number of publications have already resulted from the research and several more are in preparation. Additionally a number of areas for further study have been identified some of which are already underway as funded research and development projects