Orthogonal Fault Tolerance for Dynamically Adaptive Systems

TL;DR

This paper introduces an orthogonal fault tolerance model for dynamically adaptive systems, enabling separation and analysis of multiple fault tolerance mechanisms to improve dependability in evolving environments.

Contribution

It presents a novel orthogonal fault tolerance approach that manages feature interactions and inconsistencies using state machine semantics and verification tools.

Findings

Effective separation of fault tolerance concerns

Ability to simulate and verify fault interactions

Improved reasoning about dependability in adaptive systems

Abstract

In dynamic systems that adapt to users' needs and changing environments, dependability needs cannot be avoided. This paper proposes an orthogonal fault tolerance model as a means to manage and reason about multiple fault tolerance mechanisms that co-exist in dynamically adaptive systems. One of the key challenges associated with dynamically evolving fault tolerance needs is the feature interaction problem arising from the integration of fault tolerance features. The proposed approach provides a separation of fault tolerance concerns to study the effects of integrated fault tolerance on the system. This approach uses state machine and operational semantics to reason about these interactions and inconsistencies. The proposed approach is supported by the tool NuSMV to simulate and verify the state machines against logic statements.