Quality evaluation by QADA

Software quality is one of the major issues with software intensive systems. Quality is especially important in software product families exploiting a single set of components and common architecture in a set of products. Therefore, software quality should be evaluated as early as possible, for example, using the descriptions of software architecture. Quality properties, such as maintainability and extensibility, can be evaluated in the development phase. These properties are called evolution qualities. Others, like reliability and performance, are intertwined with the functionality of a system and thus observable only at run-time. In order to be able to evaluate quality at the architectural level, quality properties have to be defined and represented in architectural models, as derived from the requirements specifications of a product (family). Current modelling approaches do not support representation of variability and quality requirements, or traceability of quality from requirements to designs and code. Our contribution is the QADA® (Quality-driven Architecture Design and quality Analysis) methodology that provides a set of methods and techniques for developing high-quality software architectures for single systems and system families. The methodology is initially targeted at the development of service architectures applied in distributed networked systems