Improved Availability and Reliability Using Re-configuration Algorithm for Task or Process in a Flight Critical Software

Abstract

Traditionally in avionics, Federated Architecture (FA) is used where each function has its own independent, dedicated fault-tolerant computing resources. FA though has the advantage of inherent fault containment but envelops a potential risk of massive use of resources resulting in increase in weight, increase in looming, cost and maintenance. Integrated Modular Avionics architecture (IMA) is successful, as it has an efficient and effective management of hardware and software computing. Most of the applications designed on IMA currently do not have dynamic reconfiguration. The paper presents a new method for re-configuration of tasks or a process in an embedded avionics application. The proposed algorithm works based on four control parameters: re-configurability Information factor, Schedulability Test/TL/UF, Context Adaptability/suitability and Context Flight Safety. The algorithm is data centric and interfaces system health as control input and initiation of the re-configuration is only after successful evaluation of the parameter metrics. It enhances the availability and reliability of the system under failed conditions by efficient selection and procedural re-configuration with safe state exit. The advantage of the new approach over the non-configurable systems is the increased availability of flight critical applications under failed conditions. It also preserves the advantages of non-Reconfigurable systems over federated architecture. Invalid failure of control parameter brings the system to safe state. The scheme, algorithm and the control parameters metrics and their validation approach are described. The algorithm provides very good availability of the system even under failures.