Hybrid Log-based Fault Tolerant Scheme for Mobile Computing System

Author(s):  
Zhenpeng Xu ◽  
Hairong Chen ◽  
Weini Zeng

Many new characteristics are introduced in the mobile computing system, such as mobility, disconnections, finite power source, vulnerable to physical damage, lack of stable storage. Many log-based rollback recovery fault tolerant schemes were proposed according to the characteristics. However, these schemes may still lead to dramatic loss of computing performance in failure-free or inconsistent recovery after the process fault. In this paper, a hybrid log-based fault tolerant scheme is proposed combining the checkpointing mechanism with the message logging mechanism. The checkpoint, the logs and the happened-before relations are logged synchronously into the memory at local mobile hosts temporarily, and asynchronously into the persistent disk storage in the form of the antecedence graph at local mobile support station. The proposal supports the independent and propagated consistent recovery. By contrast, the results show that the proposal incurs a lower failure-free overhead on the premise of the consistent recoverability.

Author(s):  
Zhenpeng Xu ◽  
Hairong Chen ◽  
Weini Zeng

For the traditional distributed computing system, the related message logging conditions had specified to keep the state consistence among the distributed process. Since many new characteristics are introduced in the mobile computing system, the new sufficient logging requirement for mobile computing has to be specified, to avoid the possible state inconsistence among the mobile nodes and the static nodes during the rollback recovery. Firstly, the related definitions of the inconsistence among the process state and the nondeterministic event were extended in the paper, independent of the specific log-based fault tolerant scheme. Finally, a novel particular logging consistency condition was derived based on the extended definitions and Piece-Wise Deterministic model for the mobile computing system. By contrast, the proposal is a practical and efficient constraint for mobile computing upon the possible failures.


2008 ◽  
Vol 50 (5) ◽  
Author(s):  
Koen De Bosschere

AbstractOver the last decades, we have witnessed an exponential increase in sequential computing performance, but since few years this progress is slowing down. This paper describes the current evolutions in technology and architecture that cause this slowdown, and lists the major research challenges that need to be tackled in the coming years to further continue this exponential performance growth. If the computing industry fails to solve these challenges soon, this will for the first time lead to a stop of the exponential performance growth, which might eventually impact the economic growth of western economies.


Author(s):  
Pierre Kirisci ◽  
Ernesto Morales Kluge ◽  
Emanuel Angelescu ◽  
Klaus-Dieter Thoben

During the last two decades a lot of methodology research has been conducted for the design of software user interfaces (Kirisci, Thoben 2009). Despite the numerous contributions in this area, comparatively few efforts have been dedicated to the advancement of methods for the design of context-aware mobile platforms, such as wearable computing systems. This chapter investigates the role of context, particularly in future industrial environments, and elaborates how context can be incorporated in a design method in order to support the design process of wearable computing systems. The chapter is initiated by an overview of basic research in the area of context-aware mobile computing. The aim is to identify the main context elements which have an impact upon the technical properties of a wearable computing system. Therefore, we describe a systematic and quantitative study of the advantages of context recognition, specifically task tracking, for a wearable maintenance assistance system. Based upon the experiences from this study, a context reference model is proposed, which can be considered supportive for the design of wearable computing systems in industrial settings, thus goes beyond existing context models, e.g. for context-aware mobile computing. The final part of this chapter discusses the benefits of applying model-based approaches during the early design stages of wearable computing systems. Existing design methods in the area of wearable computing are critically examined and their shortcomings highlighted. Based upon the context reference model, a design approach is proposed through the realization of a model-driven software tool which supports the design process of a wearable computing system while taking advantage of concise experience manifested in a well-defined context model.


Author(s):  
Yongning Zhai ◽  
Weiwei Li

For the distributed computing system, excessive or deficient checkpointing operations would result in severe performance degradation. To minimize the expected computation execution of the long-running application with a general failure distribution, the optimal equidistant checkpoint interval for fault tolerant performance optimization is analyzed and derived in this paper. More precisely, the optimal checkpointing period to determine the proper checkpoint sequence is proposed, and the derivation of the expected effective rate of the defined computation cycle is introduced. Corresponding to the maximal expected effective rate, the constraint of the optimal checkpoint sequence can be obtained. From the constraint of optimality, the optimal equidistant checkpoint interval can be obtained according to the minimal fault tolerant overhead ratio. By the numerical results, the proposal is practical to determine a proper equidistant checkpoint interval for fault tolerant performance optimization.


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