Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!ames!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!ucla-cs!uci-ics!nancy From: nancy@ics.uci.edu (Nancy Leveson) Newsgroups: comp.software-eng Subject: Re: Software Failure Analysis Keywords: Software failure analysis, quantization errors, resolution Message-ID: <1989Sep30.034337.9238@paris.ics.uci.edu> Date: 30 Sep 89 03:43:37 GMT References: <10743@dasys1.UUCP> <34348@regenmeister.uucp> <592@halley.UUCP> <290@cs.nps.navy.mil> <27545@shemp.CS.UCLA.EDU> Sender: news@paris.ics.uci.edu (Network News) Reply-To: Nancy LevesonOrganization: University of California, Irvine - Dept of ICS Lines: 30 Besides the papers that Tim Shimeall mentions on failure analysis, there is also a set of papers on "software safety" that describe how to apply to software some of the same types of failure analysis done in engineering. If you are interested in this, one place to start is: Leveson, N.B. "Software Safety: Why, What and How," ACM Computing Surveys, Vol 18, No. 2, June 1986. This contains a lot of references. With respect to the letter by Jia Hong Chen about John Knight and my experiment, I have seen only an earlier paper by Peter Bishop in which he attempted to explain our results as having been a result of "failure masking." Unfortunately, this does not explain the results, but Peter was hampered by not having the detailed data from our experiment needed to know this. For those interested, there will be a paper appearing this spring in IEEE Transactions on Software Engineering that provides a detailed explanation of the faults that led to statistically dependent failures in our original experiment along with a model that attempts to explain this phenomena. There has also been a replication of our experiment -- they got the same results as we did. Analysis of the program failure behavior of the programs developed for an n-version programming experiment in which UCLA was one of the 4 participating universities showed virtually identical results with the Knight and Leveson experiment. nancy leveson -- Nancy Leveson