Current mainstream software engineering methods rarely consider dependability issues in the requirements engineering and analysis stage. If at all, they only address it much later in the development cycle. Concurrent, distributed, or heterogeneous applications, however, are often deployed in increasingly complex environments. Such systems, to be dependable and to provide highly available services, have to be able to cope with abnormal situations or failures of underlying components. This paper presents an overview of the software development approaches that address dependability requirements and other non-functional requirements like timeliness, adaptability and quality of service. Software development methods, frameworks, middleware, and other proposed approaches that integrate the concern of fault tolerance into the early software development stages have been studied. The paper concludes with a comparison of the various approaches based on several criteria.
