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The Infeasibility of Quantifying the Reliability of Life-Critical Real-Time SoftwareThis paper affirms that the quantification of life-critical software reliability is infeasible using statistical methods whether applied to standard software or fault-tolerant software. The classical methods of estimating reliability are shown to lead to exhorbitant amounts of testing when applied to life-critical software. Reliability growth models are examined and also shown to be incapable of overcoming the need for excessive amounts of testing. The key assumption of software fault tolerance separately programmed versions fail independently is shown to be problematic. This assumption cannot be justified by experimentation in the ultrareliability region and subjective arguments in its favor are not sufficiently strong to justify it as an axiom. Also, the implications of the recent multiversion software experiments support this affirmation.
Document ID
Document Type
Preprint (Draft being sent to journal)
Butler, Ricky W.
(NASA Langley Research Center Hampton, VA, United States)
Finelli, George B.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 1991
Subject Category
Computer Programming And Software
Distribution Limits
Work of the US Gov. Public Use Permitted.
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