Reidar Conradi

Version models for software configuration management

After more than 20 years of research and practice in software configuration management (SCM), constructing consistent configurations of versioned software products still remains a challenge. This article focuses on the version models underlying both commercial systems and research prototypes. It provides an overview and classification of different versioning paradigms and defines and relates fundamental concepts such as revisions, variants, configurations, and changes. In particular, we focus on intensional versioning, that is, construction of versions based on configuration rules. Finally, we provide an overview of systems that have had significant impact on the development of the SCM discipline and classify them according to a detailed taxonomy.

Impact of software engineering research on the practice of software configuration management

Software Configuration Management (SCM) is an important discipline in professional software development and maintenance. The importance of SCM has increased as programs have become larger, more long lasting, and more mission and life critical. This article discusses the evolution of SCM technology from the early days of software development to the present, with a particular emphasis on the impact that university and industrial research has had along the way. Based on an analysis of the publication history and evolution in functionality of the available SCM systems, we trace the critical ideas in the field from their early inception to their eventual maturation in commercially and freely available SCM systems. In doing so, this article creates a detailed record of the critical value of SCM research and illustrates how research results have shaped the functionality of todays SCM systems.

An empirical study of software reuse vs. defect-density and stability

The paper describes results of an empirical study, where some hypotheses about the impact of reuse on defect-density and stability, and about the impact of component size on defects and defect-density in the context of reuse are assessed, using historical data (data mining) on defects, modification rate, and software size of a large-scale telecom system developed by Ericsson. The analysis showed that reused components have lower defect-density than non-reused ones. Reused components have more defects with highest severity than the total distribution, but less defects after delivery, which shows that that these are given higher priority to fix. There are an increasing number of defects with component size for non-reused components, but not for reused components. Reused components were less modified (more stable) than non-reused ones between successive releases, even if reused components must incorporate evolving requirements from several application products. The study furthermore revealed inconsistencies and weaknesses in the existing defect reporting system, by analyzing data that was hardly treated systematically before.

Assessing process-centered software engineering environments

Process-centered software engineering environments (PSEEs) are the most recent generation of environments supporting software development activities. They exploit an representation of the process (called the process model that specifies how to carry out software development activities, the roles and tasks of software developers, and how to use and control software development tools. A process model is therefore a vehicle to better understand and communicate the process. If it is expressed in a formal notation, it can be used to support a variety of activities such as process analysis, process simulation, and process enactment. PSEEs provide automatic support for these activities. They exploit languages based on different paradigms, such as Petri nets and rule-based systems. They include facilities to edit and analyze process models. By enacting the process model, a PSEE provides a variety of services, such as assistance for software developers, automation of routine tasks, invocation and control of software development tools, and enforcement of mandatory rules and practices. Several PSEEs have been developed, both as research projects and as commercial products. The initial deployment and exploitation of this technology have made it possible to produce a significant amount of experiences, comments, evaluations, and feedback. We still lack, however, consistent and comprehensive assessment methods that can be used to collect and organize this information. This article aims at contributing to the definition of such methods, by providing a systematic comparison grid and by accomplishing an initial evaluation of the state of the art in the field. This evaluation takes into account the systems that have been developed by the authors in the past five years, as well as the main characteristics of other well-known environments

Adoption of open source software in software-intensive organizations - A systematic literature review

Context: Open source software (OSS) is changing the way organizations develop, acquire, use, and commercialize software. Objective: This paper seeks to identify how organizations adopt OSS, classify the literature according to these ways of adopting OSS, and with a focus on software development evaluate the research on adoption of OSS in organizations. Method: Based on the systematic literature review method we reviewed publications from 24 journals and seven conference and workshop proceedings, published between 1998 and 2008. From a population of 24,289 papers, we identified 112 papers that provide empirical evidence on how organizations actually adopt OSS. Results: We show that adopting OSS involves more than simply using OSS products. We moreover provide a classification framework consisting of six distinctly different ways in which organizations adopt OSS. This framework is used to illustrate some of the opportunities and challenges organizations meet when approaching OSS, to show that OSS can be adopted successfully in different ways, and to organize and review existing research. We find that existing research on OSS adoption does not sufficiently describe the context of the organizations studied, and it fails to benefit fully from related research fields. While existing research covers a large number of topics, it contains very few closely related studies. To aid this situation, we offer directions for future research. Conclusion: The implications of our findings are twofold. On the one hand, practitioners should embrace the many opportunities OSS offers, but consciously evaluate the consequences of adopting it in their own context. They may use our framework and the success stories provided by the literature in their own evaluations. On the other hand, researchers should align their work, and perform more empirical research on topics that are important to organizations. Our framework may be used to position this research and to describe the context of the organization they are studying.

Techniques for process model evolution in EPOS

The authors categorize some aspects of software process evolution and customization, and describe how they are handled in the EPOS PM system. Comparisons are made to other PM systems. A process model in EPOS consists of a schema of classes and meta-classes, and its model entities and relationships. There is an underlying software engineering database, EPOSDB, offering uniform versioning of all model parts and a context of nested cooperating transactions. Then, there is a reflective object-oriented process specification language, on top of the EPOSDB. Policies for model creation, composition, change, instantiation, refinement, and enaction are explicitly represented and are used by a set of PM automatic tools. The main tools are a planner to instantiate tasks, an execution manager to enact such tasks, and a PM manager to define, analyze, customize, and evolve the process schema. >

Quality, productivity and economic benefits of software reuse: a review of industrial studies

Systematic software reuse is proposed to increase productivity and software quality and lead to economic benefits. Reports of successful software reuse programs in industry have been published. However, there has been little effort to organize the evidence systematically and appraise it. This review aims to assess the effects of software reuse in industrial contexts. Journals and major conferences between 1994 and 2005 were searched to find observational studies and experiments conducted in industry, returning eleven papers of observational type. Systematic software reuse is significantly related to lower problem (defect, fault or error) density in five studies and to decreased effort spent on correcting problems in three studies. The review found evidence for significant gains in apparent productivity in three studies. Other significant benefits of software reuse were reported in single studies or the results were inconsistent. Evidence from industry is sparse and combining results was done by vote-counting. Researchers should pay more attention to using comparable metrics, performing longitudinal studies, and explaining the results and impact on industry. For industry, evaluating reuse of COTS or OSS components, integrating reuse activities in software processes, better data collection and evaluating return on investment are major challenges.

Effort estimation of use cases for incremental large-scale software development

This paper describes an industrial study of an effort estimation method based on use cases, the use case points method. The original method was adapted to incremental development and evaluated on a large industrial system with modification of software from the previous release. We modified the following elements of the original method: a) complexity assessment of actors and use cases, and b) the handling of non-functional requirements and team factors that may affect effort. For incremental development, we added two elements to the method: c) counting both all and the modified actors and transactions of use cases, and d) effort estimation for secondary changes of software not reflected in use cases. We finally extended the method to: e) cover all development effort in a very large project. The method was calibrated using data from one release and it produced an estimate for the successive release that was only 17% lower than the actual effort. The study identified factors affecting effort on large projects with incremental development. It also showed how these factors can be calibrated for a specific context and produce relatively accurate estimates.

A SURVEY OF CASE STUDIES OF THE USE OF KNOWLEDGE MANAGEMENT IN SOFTWARE ENGINEERING

This article examines the literature on case studies of knowledge management systems in use in organisations that develop software. We investigate knowledge management approaches in eight case studies, and what the reported benefits are. Surprisingly, very few organisations claim to have lowered software production costs or increased the quality of the software. But many claim to have improved the work situation for software developers and managers.

The REBOOT approach to software reuse

Although some companies have been successful in software reuse, many research projects on reuse have had little industrial penetration. Often the proposed technology has been too ambitious or exotic, or did not scale up. REBOOT emphasizes industrial applicability of the proposed technology in a holistic perspective: a validated method through a Methodology Handbook, a stabilized tool set around a reuse library, a training package, and initial software repositories of reusable components extracted from company-specific projects. This article presents the REBOOT approach to software reuse, covering both organizational and technical aspects and the experiences so far from the applications.