Product lines are a promising approach to improve conceptually the productivity of the software development process and thus to reduce both the cost and time of developing and maintaining increasingly complex systems. An important issue in the adoption of the product-line approach is the migration of legacy software components, which have not been designed for reuse, systematically into reusable product-line components. This article describes activities performed to improve systematically the design and implementation of an existing software component in order to reuse it in a software product line. The activities are embedded in the application of Fraunhofer PuLSE TM -DSSA-an approach for defining domain-specific software architectures (DSSA) and product-line architectures. The component under investigation is the so-called Image Memory Handler (IMH), which is used in Ricoh's current products of office appliances such as copier machines, printers, and multi-functional peripherals. It is responsible for controlling memory usage and compressing and decompressing image data. Improvement of both the component's design and implementation are based on a systematic analysis and focused on increasing maintainability and reusability and hence suitability for use in a product line. As a result of the analysis and refactoring activities, the documentation and implementation of the component has been considerably improved as shown by quantitative data collected at the end of the activities. Despite a number of changes to the code, the external behavior of the component has been preserved without significantly affecting the performance. INTRODUCTIONOrganizations developing software face a number of challenges today. In particular, there is a critical need to reduce the cost, effort, and time-to-market of software, but, at the same time, the complexity and size of systems are rapidly increasing and customers are requesting increasingly quality systems tailored to their individual needs [1].A promising approach to improve conceptually the productivity of the software development process and thus to reduce both cost and time of developing and maintaining increasingly complex systems is the notion of software product lines [2]. Product-line software engineering refers to techniques for creating a collection of similar software systems from a shared set of software assets using a common means of production. A software product line is defined as a family of products designed to take advantage of their common aspects and predicted variability [3]. Product-line engineering is based on strategic reuse as opposed to opportunistic reuse, which usually comes into play in single-system development. Strategic reuse means that attributes of software such as generality, modularity, environment independence, and self-descriptiveness are planned and implemented with respect to the predictable benefits concerning customer needs and market trends. In product-line engineering, the overall development life cycle is split into two concurrent phase...

This paper describes activities performed to systematically improve the design and implementation of an existing software component in order to reuse it in a software product line. The activities are embedded in the application of Fraunhofer's PuLSE-DSSA approach for defining the architecture of a new product line. The component under investigation is the so called Image Memory Handler (IMH) which is used in Ricoh's current products of office appliances such as copier machines, printers, and multi-functional peripherals. It is responsible for controlling memory usage and compressing and decompressing image data. Both the improvement of the component's design and implementation are based on a systematic analysis and focused on increasing maintainability and reusability and hence suitability for use in a product line

Product line engineering is a recent approach to software development that has shown to enable organizations to achieve significant reductions in development and maintenance cost as well as time-to-market of increasingly complex software systems. Yet, the testing process has not kept up with these reductions and the relative cost for testing product lines is actually becoming higher than in traditional single system development. Also, testing often cannot keep pace with accelerated development in product line engineering due to technical and organizational issues. This paper advocates that testing of product lines can be made more efficient and effective by considering testability already during architectural design. It explores the relationship between testability and product line architecture and discusses the importance of high testability for reducing product line testing effort and achieving required coverage criteria. The paper also outlines a systematic approach that will support product line organizations in improving and evaluating testability of product lines at the architectural level

In recent years, product line development has increasingly received attention in industry as it enables software-developing organizations to reduce both cost and time of developing and maintaining increasingly complex systems as well as to address the demands for individually customized products. Successful product line development requires high quality of reusable artifacts in order to achieve the promised benefits. The unique issues of quality assurance in the context of systematic reuse, however, have not been quantitatively investigated so far. This paper describes a first empirical study comparing the two defect detection techniques, code inspections and functional testing, in the context of product line development. The primary goal of the study was to initially investigate the defect finding potential of the techniques on reusable software components with common and variant features. The major findings of the study are that the two techniques identified different types of defects on variants of a reusable component. Inspections are on average 66.39% more effective and need on average 36.84% less effort to detect a defect We found that both the testing and inspection techniques applied in the experiment were ineffective in identifying variant-specific defects. Overall, the results indicate that the standard quality assurance techniques seem to be insufficient to address special characteristics of reusable components.

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