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BEGIN:VEVENT
DTEND:20210319T120000Z
UID:2dd7cc1e0e7836480f7ca4d5fe73f8ae-135
DTSTAMP:19700101T120019Z
DESCRIPTION:Software Fault Tolerance via Environmental Diversity
URL;VALUE=URI:https://www.csa.iisc.ac.in/newweb/event/135/software-fault-tolerance-via-environmental-diversity/
SUMMARY:Time: 7 PM with online Networking at 6.30 PM<br>
Meeting Link: <a href="http://bit.do/vvssarma">http://bit.do/vvssarma</a>
<br>
Complex systems in different domains contain significant amount of software. Several  studies have established that a significant fraction of system outages are due to software faults. Traditional methods of fault avoidance, fault removal based on extensive testing/debugging, and fault tolerance based on design/data diversity are found inadequate to ensure high software dependability. The key challenge then is how to provide highly dependable software. We discuss a viewpoint of fault tolerance of software-based systems to ensure high dependability. We classify software faults into Bohr bugs and Mandel bugs, and identify aging-related bugs as a subtype of the latter. Traditional methods have been designed to deal with Bohr bugs. The next challenge then is to develop mitigation methods for Mandel bugs in general and aging-related  bugs in particular. We submit that mitigation methods for Mandel bugs utilize environmental diversity. Retry operation, restart application, failover to an identical replica (hot, warm or cold) and reboot the OS are examples of mitigation techniques that rely on environmental diversity.  For software aging related bugs it is also possible to utilize proactive environmental diversity technique known as software rejuvenation. We discuss environmental diversity both from experimental and analytic points of view and cite examples of real systems employing these techniques.
DTSTART:20210319T120000Z
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