Abstract. Various software architecture viewpoint approaches have been introduced to model the architecture views for stakeholder concerns. To address quality concerns in software architecture views, an important approach is to define architectural perspectives that include a collection of activities, tactics and guidelines that require consideration across a number of the architectural views. Several architectural perspectives have been defined for selected quality concerns. In this paper we propose the Safety Perspective that is dedicated to ensure that the safety concern is properly addressed in the architecture views. The proposed safety perspective can assist the system and software architects in designing, analyzing and communicating the decisions regarding safety concerns. We illustrate the safety perspective for a real industrial case study and discuss the lessons learned.

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Abstract.Currently, an increasing number of systems are controlled by software and rely on the correct operation of software. In this context, a safetycritical system is defined as a system in which malfunctioning software could result in death, injury or damage to environment. To mitigate these serious risks, the architecture of safety-critical systems needs to be carefully designed and analyzed. A common practice for modeling software architecture is the adoption of software architecture viewpoints to model the architecture for particular stakeholders and concerns. Existing architecture viewpoints tend to be general purpose and do not explicitly focus on safety concerns in particular. To provide a complementary and dedicated support for designing safety critical systems, we propose an architecture framework for software safety. The architecture framework is based on a metamodel that has been developed after a thorough domain analysis. The framework includes three coherent viewpoints, each of which addressing an important concern. The application of the viewpoints is illustrated for an industrial case of safety-critical avionics control computer system.

Software development governance can be defined as the application of "governance" in software engineering in order to increase the probability of success in the level of individual projects as well as in the level of the organization comprising many interrelated projects. The topic deserves an interdisciplinary perspective, as the general subject of governance has been analyzed quite extensively under the field of Transaction Cost Economics. This interdisciplinary approach enabled the identification of three main modes of governance for software engineering, namely: top-down governance, bottom-up governance and reuse governance, each having unique transaction cost characteristics. To be cost effective, (1) the organizations should adapt the right governance structure for their projects based on their characteristics, and (2) the software development tools should support and be in alignment with the underlying governance structure. In this chapter, we briefly overview the first premise and then outline an approach to address the second premise, specifically tackling the issue of tools integration, for software modeling and configuration management tools. We use Dependency Structure Matrix (DSM) to represent the mapping between governance structures and software modules, propose a configuration management approach for each mode of software governance, and demonstrate a successful integration using Lattix LDM, IBM Rational ClearCase and IBM Rational Rhapsody, three broadly available tools in the software industry.

A safety-critical system is a system in which the software malfunctioning could result in death, injury, or damage to the environment. Addressing safety concerns early on at the architecture design level is critical to guide the subsequent life cycle activities to ensure that the eventual system is reliable. A fundamental approach to address safety at the design level is the adoption of architectural tactics. It is crucial for safety-critical systems to correctly implement the constraints as defined by the selected safety tactics. This article proposes a systematic approach for assessing the adequacy of test suites of safety-critical systems based on these architectural safety tactics. We use a case study to evaluate the effectiveness of our approach using fault-injection techniques. Our study shows that this systematic approach is feasible and effective for test suite assessment of safety-critical systems.