Program Comprehension is a key factor in providing effective software maintenance and enabling successful evolution of software systems. The objective of this research is to provide a framework and mechanism to facilitate the understanding of large software systems. There exist a number of theories and models of Program Comprehension where each favours a different approach to comprehension. It is evident that there is no real consensus on how maintainers understand software systems. The disparities in the comprehension strategies are largely dependent on the personal and circumstantial factors. Factors such as the level of technical competence of the maintainers, the size and complexity of the piece of software, and the types and goals of the maintenance activities can influence the process of comprehension. This research proposes an alternative approach to Program Comprehension. It acknowledges that the process of comprehension is opportunistic, and that the current comprehension theories are inadequate in addressing this. There is a need for a more flexible approach towards comprehension, and the Integrated Approach proposed in this thesis provides a way for the utilisation of the various comprehension theories under a single environment. It recognises that any one of the comprehension theories may become active during comprehension. Under the Integrated Approach, maintainers have the option of selecting and executing the various comprehension strategies as they see fit. The Integrated Approach to comprehension is based on a matrix of Program Relationships between Program Elements of a programming language. In this thesis, these Program Relationships are derived for the C programming language constructs. This work also involves the investigation of the roles of both textual and graphical representations during the comprehension process. Both representations are commonly used to alleviate the problem of information overloading when maintainers trying to understand and maintain a software system. The Integrated Approach is realised in a tool named PUI (program understanding implements) which provides an environment enabling the utilisation of various comprehension theories.

This thesis presents and analyses a solution to the problem of formally re- engineering program data structures, allowing new representations of a program to be developed. The work is based around Ward's theory of program transformations which uses a Wide Spectrum Language, WSL, whose semantics were specially developed for use in proof of program transformations. The re-engineered code exhibits equivalent functionality to the original but differs in the degree of data abstraction and representation. Previous transformational re-engineering work has concentrated upon control flow restructuring, which has highlighted a lack of support for data restructuring in the maintainer's tool-set. Problems have been encountered during program transformation due to the lack of support for data re-engineering. A lack of strict data semantics and manipulation capabilities has left the maintainer unable to produce optimally re-engineered solutions. It has also hindered the migration of programs into other languages because it has not been possible to convert data structures into an appropriate form in the target language. The main contribution of the thesis is the Data Re-Engineering and Abstraction Mechanism (DREAM) which allows theories about type equivalence to be represented and used in a re-engineering environment. DREAM is based around the technique of "ghosting", a way of introducing different representations of data, which provides the theoretical underpinning of the changes applied to the program. A second major contribution is the introduction of data typing into the WSL language. This allows DREAM to be integrated into the existing transformation theories within WSL. These theoretical extensions of the original work have been shown to be practically viable by implementation within a prototype transformation tool, the Maintainer's Assistant. The extended tool has been used to re-engineer heavily modified, commercial legacy code. The results of this have shown that useful re-engineering work can be performed and that DREAM integrates well with existing control flow transformations.

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.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1988. / Vita. Abstract. Includes bibliographical references (leaves 80-82). Also available via the Internet.

Dissertation--Universität Kiel, 2009. / Includes bibliographical references (p. [227]-244).

It is within highly integrated technology environments that information security is becoming a focal point for designing, developing and deploying software applications. Ensuring a high level of trust in the security and quality of these applications is crucial to their ultimate success. Therefore, information security has become a core requirement for software applications, driven by the need to protect critical assets and the need to build and preserve widespread trust in computing. However, a common weakness that is inherent in the traditional software development methodologies is the lack of attention given to the security aspects of software development. Most of these methodologies do not explicitly include a standardised method for incorporating information security into their life cycles. Meaningful security can be achieved when information security issues are considered as part of a routine development process, and security safeguards are integrated into the software application throughout its life cycle. This, in turn, will lead to users being more confident to use software applications, and to entrust today's computer systems with their personal information. To build better or more secure software, an improved software development process is required. Security of a software application must be based on the risk associated with the application. In order to understand this risk, the relevant information assets need to be identified together with their threats and vulnerabilities. Therefore, security considerations provide input into every phase of the Software Development Life Cycle (SDLC), from requirements gathering to design, implementation, testing and deployment. This research project presents a Secure Software Development Model (SecSDM) for incorporating information security into all phases of the SDLC, from requirements gathering to systems maintenance. The SecSDM is based on many of the recommendations provided by relevant international standards and best practices, for example, the ISO 7498-2 (1989) standard which addresses the underlying security services and mechanisms that form an integral part of the model.

No description available.

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.

The problem area addressed in this thesis is extraction of a data design from existing data intensive program code. The purpose of this is to help a software maintainer to understand a software system more easily because a view of a software system at a high abstraction level can be obtained. Acquiring a data design from existing data intensive program code is an important part of reverse engineering in software maintenance. A large proportion of software systems currently needing maintenance is data intensive. The research results in this thesis can be directly used in a reverse engineering tool. A method has been developed for acquiring data designs from existing data intensive programs, COBOL programs in particular. Program transformation is used as the main tool. Abstraction techniques and the method of crossing levels of abstraction are also studied for acquiring data designs. A prototype system has been implemented based on the method developed. This involved implementing a number of program transformations for data abstraction, and thus contributing to the production of a tool. Several case studies, including one case study using a real program with 7000 Hues of source code, are presented. The experiment results show that the Entity-Relationship Attribute Diagrams derived from the prototype can represent the data designs of the original data intensive programs. The original contribution of the thesis is that the approach presented in this thesis can identify and extract data relationships from the existing code by combining analysis of data with analysis of code. The approach is believed to be able to provide better capabilities than other work in the field. The method has indicated that acquiring a data design from existing data intensive program code by program transformation with human assistance is an effective method in software maintenance. Future work is suggested at the end of the thesis including extending the method to build an industrial strength tool.

O volume crescente de software em funcionamento em todo tipo de organização vem despertando atenção para uma fase do ciclo de vida de software, até então considerada sempre de maneira secundária, a manutenção de software. O fato de geralmente não ser viável substituir os produtos de software de uma organização por outros baseados em tecnologias mais recentes, torna a manutenção daqueles sistemas legados um desafio adicional para a busca de técnicas e métodos para a manutenção de software. Os problemas oriundos dessa atividade precisam ser melhor compreendidos, e é justamente na definição e estudo dessas dificuldades que este trabalho se dedica. O confronto da teoria de engenharia de software com observações práticas conduz para a melhor definição de quais são os problemas típicos de manutenção de software e do que se dispõe para abordá-los. Finalmente, com base no entendimento formado sobre os problemas, neste trabalho são apresentdas diretrizes para guiar a elaboração de uma disciplina específica de manutenção de software para cursos de graduação na área de computação / The increasing volume of software being used in all types of organizations has been calling attention for a phase of the software life cycle, until now considered in a secondary way, the software maintenance. Since it is generally not possible to replace all software products used in an organization by others based on more recent technologies, the maintenance of those legacy systems becomes one more challenge for the search of techniques and methods to handle the software maintenance efficiently. The problems arising from this activity need to be better understood, and it is precisely on the definition and study of these difficulties that this work is devoted. The confrontation between the theory of software engineering and practice observations drives to the definition of typical problems of software maintenance and what exists to solve them. Besides, based on the understanding about these problems, this work also presents guidelines to drive the elaboration of a specific discipline of software maintenance for undergraduate courses in computing area