Programming-level and redundancy-free method for enhancing software reliability against transient errors in hardware

Software play remarkable roles in different critical applications. On the other hand, due to the shrinking of transistor size and reduction in supply voltage, radiation-induced transient errors (soft errors) have become an important source of computer systems failure. As the rate of transient hardware faults increases, researchers have investigated software techniques to control these faults. Performance overhead is the main drawback of software-implemented methods like recovery blocks that use technical redundancy. Enhancing the software reliability against soft errors by utilizing inherently error masking (invulnerable) programming structures is the main goal of this study. During the programming phase and at the source code level, programmers can select different storage classes such as automatic, global, static and register for the data into their program without paying attention to their inherent reliability. In this study, the inherent effects of these storage classes on the program reliability are investigated. Extensive series of profiling and fault-injection experiments were performed on the set of benchmark programs implemented with different storage classes. Regarding the results of experiments, we find that the programs implemented with automatic storage classes have inherently higher reliability than the programs with static and register storage classes without performance overhead. This finding enables the programmers to develop highly reliable programs without technical redundancy and performance overhead.

Investigations on Corrosion Behaviors of Super-Strength Sucker Rod Steel in High SO42- Environment

In some sour reservoirs and tertiary oil recovery blocks, SO42- in solution can cause the corrosion and corrosion fatigue of the sucker rods. In this paper, the corrosion behaviors of super-strength sucker rod FG20 (16Mn2SiCrMoVTiA) steel in the well fluid are investigated by electrochemical measurements, and electron probe micro-analyzer (EPMA) analysis. The results show that FG20 steel has a favorable corrosion resistance in neural solutions. When the hydrogen ion content increases, the hydrolysis of SO42- greatly accelerates the corrosion of FG20 steel. The energy dispersive X-ray(EDX)results demonstrate that the corrosion process of FG20 steel in neural well liquid is an oxygen concentration process, and the protective FeCO3 and Fe2O3 on the surface of the samples can prevent further corrosion. With the increase of the acidity in the well liquid, the corrosion process converts into a sulphide concentration process, and the sloppy FeS and mackinawite film cannot provide effective protection for the specimens, resulting in the increase of corrosion rate.

Fault-Tolerant Protocols Using Single- and Multiple-Version Software Fault-Tolerance

This chapter discusses two large classes of fault-tolerance protocols: • Single-version protocols, that is, methods that use a non-distributed, single task provision, running side-by-side with the functional software, often available in the form of a library and a run-time executive. • Multiple-version protocols, which are methods that use actively a form of redundancy, as explained in what follows. In particular recovery blocks and N-version programming will be discussed. The two families have been grouped together in this chapter because of the several similarities they share.