On Architecting Software Fault Tolerance using Abstractions

In this position paper, we argue how architectural abstractions can be effective in developing fault-tolerant software systems. Depending on the fault model and the resources available, different abstractions can be employed for representing architectural issues related to fault tolerance. These architectural abstractions, and their internal views, can be instantiated into concrete components and connectors for designing fault-tolerant software architectures. Since structural and behavioural properties associated with these abstractions are formally specified, the process of verifying and validating software architectures can be automated. In this paper, we focus on two architectural abstractions: the idealised fault-tolerant architectural element (iFTE), which is based on exception handling, and the halt-on-failure architectural element (HoFE), which assumes crash failure semantics.