A Survey of Fault-Tolerance Techniques for Embedded Systems from the Perspective of Power, Energy, and Thermal Issues

The relentless technology scaling has provided a significant increase in processor performance, but on the other hand, it has led to adverse impacts on system reliability. In particular, technology scaling increases the processor susceptibility to radiation-induced transient faults. Moreover, technology scaling with the discontinuation of Dennard scaling increases the power densities, thereby temperatures, on the chip. High temperature, in turn, accelerates transistor aging mechanisms, which may ultimately lead to permanent faults on the chip. To assure a reliable system operation, despite these potential reliability concerns, fault-tolerance techniques have emerged. Specifically, fault-tolerance techniques employ some kind of redundancies to satisfy specific reliability requirements. However, the integration of fault-tolerance techniques into real-time embedded systems complicates preserving timing constraints. As a remedy, many task mapping/scheduling policies have been proposed to consider the integration of fault-tolerance techniques and enforce both timing and reliability guarantees for real-time embedded systems. More advanced techniques aim additionally at minimizing power and energy while at the same time satisfying timing and reliability constraints. Recently, some scheduling techniques have started to tackle a new challenge, which is the temperature increase induced by employing fault-tolerance techniques. These emerging techniques aim at satisfying temperature constraints besides timing and reliability constraints. This paper provides an in-depth survey of the emerging research efforts that exploit fault-tolerance techniques while considering timing, power/energy, and temperature from the real-time embedded systems’ design perspective. In particular, the task mapping/scheduling policies for fault-tolerance real-time embedded systems are reviewed and classified according to their considered goals and constraints. Moreover, the employed fault-tolerance techniques, application models, and hardware models are considered as additional dimensions of the presented classification. Lastly, this survey gives deep insights into the main achievements and shortcomings of the existing approaches and highlights the most promising ones

Implementation of middleware fault tolerance support for real-time embedded applications

Critical real-time embedded systems need to apply fault tolerance strategies to deal with operation time errors, either in hardware or software. In this paper we present the ongoing work to provide application fault tolerance by means of implementing middleware transparent support over the BOSS embedded operating system. The middleware uses a publishersubscriber protocol and enables the execution of several fault tolerance strategies with minimum burden to the application level softwareFundação para a Ciência e a Tecnologia (FCT

Application-level fault tolerance in real-time embedded systems

Critical real-time embedded systems need to make use of fault tolerance techniques to cope with operation time errors, either in hardware or software. Fault tolerance is usually applied by means of redundancy and diversity. Redundant hardware implies the establishment of a distributed system executing a set of fault tolerance strategies by software, and may also employ some form of diversity, by using different variants or versions for the same processing. This work proposes and evaluates a fault tolerance framework for supporting the development of dependable applications. This framework is build upon basic operating system services and middleware communications and brings flexible and transparent support for application threads. A case study involving radar filtering is described and the framework advantages and drawbacks are discussed.Fundação para a Ciência e a Tecnologia (FCT

Aspect-oriented fault tolerance for real-time embedded systems

Real-time embedded systems for safety-critical applications have to introduce fault tolerance mechanisms in order to cope with hardware and software errors. Fault tolerance is usually applied by means of redundancy and diversity. Redundant hardware implies the establishment of a distributed system executing a set of fault tolerance strategies by software, and may also employ some form of diversity, by using different variants or versions for the same processing. This paper describes our approach to introduce fault tolerance in distributed embedded systems applications, using aspect-oriented programming (AOP). A real-time operating system sup-porting middleware thread communication was integrated to a fault tolerant framework. The introduction of fault tolerance in the system is performed by AOP at the application thread level. The advantages of this approach include higher modularization, less efforts for legacy systems evolution and better configurability for testing and product line development. This work has been tested and evaluated successfully in several fault tolerant configurations and presented no significant performance or memory footprint costs.Fundação para a Ciência e a Tecnologia (FCT

Comparative Analysis Of Fault-Tolerance Techniques For Space Applications

Fault-tolerance technique enables a system or application to continue working even if some fault /error occurs in a system. Therefore, it is vital to choose appropriate fault tolerant technique best suited to our application. In case of real-time embedded systems in a space project, the importance of such techniques becomes more critical. In space applications, there is minor or no possibility of maintenance and faults occurrence may lead to serious consequences in terms of partial or complete mission failure. This paper describes the comparison of various fault tolerant techniques for space applications. This also suggests the suitability of these techniques in particular scenario.  The study of fault tolerance techniques relevant to real-time embedded systems and on-board space applications (satellites) is given due importance. This study will not only summarize fault tolerant techniques but also describe their strengths. The paper describes the future trends of faults-tolerance techniques in space applications. This effort may help space system engineers and scientists to select suitable fault-tolerance technique for their mission.

The embedded operating system project

This progress report describes research towards the design and construction of embedded operating systems for real-time advanced aerospace applications. The applications concerned require reliable operating system support that must accommodate networks of computers. The report addresses the problems of constructing such operating systems, the communications media, reconfiguration, consistency and recovery in a distributed system, and the issues of realtime processing. A discussion is included on suitable theoretical foundations for the use of atomic actions to support fault tolerance and data consistency in real-time object-based systems. In particular, this report addresses: atomic actions, fault tolerance, operating system structure, program development, reliability and availability, and networking issues. This document reports the status of various experiments designed and conducted to investigate embedded operating system design issues

Towards Middleware for Fault-tolerance in Distributed Real-time and Embedded Systems

Abstract. Distributed real-time and embedded (DRE) systems often require support for multiple simultaneous quality of service (QoS) properties, such as real-timeliness and fault tolerance, that operate within resource constrained environments. These resource constraints motivate the need for a lightweight middleware infrastructure, while the need for simultaneous QoS properties require the middleware to provide fault tolerance capabilities that respect time-critical needs of DRE systems. Conventional middleware solutions, such as Fault-tolerant CORBA (FT-CORBA) and Continuous Availability API for J2EE, have limited utility for DRE systems because they are heavyweight (e.g., the complexity of their feature-rich fault tolerance capabilities consumes excessive runtime resources), yet incomplete (e.g., they lack mechanisms that enable fault tolerance while maintaining real-time predictability). This paper provides three contributions to the development and standardization of lightweight real-time and fault-tolerant middleware for DRE systems. First, we discuss the challenges in realizing real-time faulttolerant solutions for DRE systems using contemporary middleware. Second, we describe recent progress towards standardizing a CORBA lightweight fault-tolerance specification for DRE systems. Third, we present the architecture of FLARe, which is a prototype based on the OMG real-time fault-tolerant CORBA middleware standardization efforts that is lightweight (e.g., leverages only those server-and client-side mechanisms required for real-time systems) and predictable (e.g., provides fault-tolerant mechanisms that respect time-critical performance needs of DRE systems)

Design and Performance of a Fault-Tolerant Real-Time CORBA Event Service

Developing distributed real-time and embedded (DRE)systems in which multiple quality-of-service (QoS) dimen-sions must be managed is an important and challenging R&D problem. This paper makes three contributions to re-search on multi-dimensional QoS for DRE systems. First, itdescribes the design and implementation of a fault-tolerantreal-time CORBA event service for The ACE ORB (TAO).Second, it describes our enhancements and extensions tofeatures in TAO, to integrate real-time and fault toleranceproperties. Third, it presents an empirical evaluation ofour approach. Our results show that with some refinements,real-time and fault-tolerance features can be integrated ef-fectively and efficiently in a CORBA event service