n-Modular Redundant Real-Time Middleware: Design and Implementation

Cyber-physical systems (CPSs) have stringent requirements for size, power, cost, and reaction time. Fault protection mechanisms negatively impact some or all of these considerations. We introduce a software-only framework that leverages the modular and robust design of CPSs to allow more flexibility in detecting and recovering from transient faults. We describe an implementation of this framework that adheres to the POSIX specification, with the exceptions of architecture specific timers, CPU pinning, and a mechanism to walk the pages of a process. The system is evaluated with a set of micro-benchmarks, simulated failure injection campaign, and with simulated tasks performed by an example CPS.