Fault detection and recovery coverage improvement by optimal clock diversity
Nobuyasu Kanekawa, Shinichiro Yamaguchi, Yosuke Shima · Systems and Computers in Japan · 2003
Abstract Enhancement of fault recovery coverage by early discovery and early recovery is indispensable in enhancing the availability of fail‐safe systems and fault‐tolerant systems. In clock‐synchronized duplicate comparison systems, errors can be detected in the clock unit, facilitating the early discovery and recovery of faults. Addition of optimal‐time diversity makes possible the prevention of error correlation in the duplicate comparison systems, which promotes coverage enhancement. This paper presents an experimental comparison of the fault detection coverage and recovery coverage of the clock‐synchronized method with optimal‐time diversity (the optimal clock diversity method), the clock‐synchronized method without optimal‐time diversity, and the loosely synchronized method. The experimental results show that the clock‐synchronized method has the highest recovery coverage and that the optimal clock diversity method has the highest fault detection coverage. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 35(1): 58–66, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/scj.10253