W.G. Bouricius, W.C. Carter, and P. Schneider, "Reliability Modeling Techniques for Self Repairing Computer Systems," Proc. 24th Nat'l Conf. the ACM, pp. 295-309, Mar. 1969.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and software engineering communities have precise definitions for the term coverage; however, they use this term in very different ways. In the dependability context, coverage is defined as the conditional probability that the system properly processes a fault, given that the specific fault occurs [9]. Later work included the assumption that the fault was activated in the probabilistic definition [3] A number of modeling and analysis strategies naturally arise from this definition. First, coverage can be mathematically represented as probability density and cumulative density functions (PDF ....

....engineering communities have studied the problems of program coverage and fault coverage extensively. Given the limited space, we will focus here on a comparison of our work with previous research on fault injection using programcoverage metrics. An understanding of probabilistic fault coverage [9], its relationship to system dependability [13] and fault injection [3] also is essential to understand the context of our work. Our program coverage metrics are most similar to those used in dataflow testing [26] These references have been discussed in Section 2.1. Our fault injection ....

W. G. Bouricius, W. C. Carter, and P. Schneider. Reliability modeling techniques for self repairing computer systems. In In Proceedings of the 24th National Conference of the ACM, pages 295--309, March 1969.

....and Systems Research Laboratory at the University of Illinois at Urbana Champaign, USA. can be achieved heavily relies on the efficiency of the fault tolerance mechanisms the fault tolerance coverage that is usually defined as the probability of system recovery given that a fault exists [Bouricius et al. 1969]. Fault tolerance mechanisms are commonly assessed by carrying out fault injection experiments [Segall et al. 1988, Chillarege Bowen 1989, Gunneflo et al. 1989, Walter 1990, Choi et al. 1991, Arlat et al. 1993, Kanawati et al. 1995] A single fault injection experiment consists of injecting a ....

W. G. Bouricius, W. C. Carter and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", in Proc. 24th National Conference, pp.295-309, ACM, 1969.

....and on techniques that can reasonably be considered to comprise self healing. For example, one view of self healing systems is that they perform a reconfiguration step to heal a system having suffered a permanent fault. The use of standby spares in such a manner has been called self repair [Bouricius69]. Systems that use modular redundancy (e.g. vonNeuman56] can tolerate component failures and might be considered to be self healing. It is premature to propose a consensus based definition of the term self healing, so we do not attempt to do this beyond an appeal to intuition that such a ....

Bouricius, W.G., Carter, W.C. & Schneider, P.R, "Reliability modeling techniques for self-repairing computer systems," Proceedings of 24th National Conference, ACM, 1969, pp. 395-309.

....an important aspect of overall system reliability. Redundant System with Imperfect Coverage Before developing the Markov method of analyzing Fault Tolerant systems, a conditional probability method will be used to derive the MTTF and MTBF for a redundant system with imperfect fault detection [Bour69] Assume that the failure rate for each subsystem of the redundant system is described by an independent 35 random variable l . Let X denote the lifetime of a system with two modules, one active and the other in standby mode. Assume that the module in the standby mode does not experience a fault ....

....section, it has been assumed that each injected fault immediately results in a observable error or system failure. In many instances, this is not the case, rather some time may pass before this effects of the injected fault is observed. Two time intervals require further analysis [Aviz86] Bour69] The fault dormancy is the time interval between the occurrence of a fault and its activation as an error. The error detection latency is the time interval between an error and its detection by the diagnostic subsystem. In addition to single faults causing observable errors, near coincident ....

Bouricius, W. G., "Reliability Modeling Techniques for Self--Repairing Computer Systems," Proceedings of the 24 National Conference of the ACM, August 1969, pp. 295--309.

....of the operational behavior of fault tolerant mechanisms (fault forecasting) The operational behavior of fault tolerant mechanisms is characterized in terms of measures such as coverage factors, dormancy, and latency. Coverage is the probability of system recovery given that a fault exists [3]. Dormancy and latency are times rather than probabilities. Dormancy is the time corresponding to the activation of an injected fault as an error. Latency is the time from the error to either failure of the system or detection and system recovery [2] Coverage estimations of fault tolerant ....

W. G. Bouricius, W. C. Carter, and P. R. Schneider, "Reliability modeling techniques for self-repairing computer systems," in Proceedings of the 24 National Conference, 1969, pp. 295-309.

....computer systems. The values to be obtained for these systems are related to how often and how quickly the fault tolerant system recovers when a fault actually occurs. These measures include coverage, latency, and dormancy. Coverage is the probability of system recovery given that a fault exists [3]. Dormancy and latency are times rather than probabilities. Dormancy is the time corresponding to the activation of an injected fault as an error. Latency is the time from the error to either failure of the system or detection and system recovery [4] Since faults are generally rare, it would ....

W. G. Bouricius, W.C. Carter, and P.R. Schneider, "Reliability modeling techniques for self-repairing computer systems," in Proceedings of the 24 National Conference,

....requirements imposed by critical applications. The degree of dependability that can be achieved heavily relies on the efficiency of the fault tolerance mechanisms the fault tolerance coverage that is usually defined as the probability of system recovery given that a fault exists [4]. Fault injection experiments are commonly carried out to assess the fault tolerance mechanisms [3, 5, 6, 8, 12, 15, 17] A single fault injection experiment consists of injecting a fault condition into a simulation or a prototype of a fault tolerant system and observing the behavior of the ....

W. G. Bouricius, W. C. Carter and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", in Proc. 24th National Conference, pp.295-309, ACM, 1969.

....system [1] If such a system is to be used in critical applications, it is particularly important to assess the efficiency of the underlying mechanisms. One measure of this efficiency is their fault tolerance coverage, defined as the probability of system recovery given that a fault exists [2]. This paper addresses the problem of estimating fault tolerance coverage by processing the observations collected in a set of fault injection experiments [3 9] A single fault injection experiment consists of injecting a fault condition into a simulation or a prototype of a fault tolerant system ....

W. G. Bouricius, W. C. Carter, and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", Proc. 24th National Conference, pp. 295-309, ACM, 1969.

....1. Introduction A central problem in the validation of fault tolerant systems is the evaluation of the efficiency of their fault tolerance mechanisms. One parameter used to quantify this efficiency is the coverage factor defined as the probability of system recovery given that a fault exists [1]. The sensitivity of dependability measures (such as reliability and availability) to small variations in the coverage factor is well known [1, 2] Consequently, it is very important to determine coverage as accurately as possible. This paper addresses the problem of obtaining accurate and useful ....

....mechanisms. One parameter used to quantify this efficiency is the coverage factor defined as the probability of system recovery given that a fault exists [1] The sensitivity of dependability measures (such as reliability and availability) to small variations in the coverage factor is well known [1, 2]. Consequently, it is very important to determine coverage as accurately as possible. This paper addresses the problem of obtaining accurate and useful estimations of coverage through the statistical processing of observations collected in fault injection experiments. This work was partially ....

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W. G. Bouricius, W. C. Carter and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", in Proc. 24th National Conference, 1969, pp. 295-309 (ACM).

....and the mean time to the occurrence of the latter event rather long. In a safety critical system, the system design should provide a long mean time to an unsafe shutdown while a short mean time to safe shutdown may be acceptable. In a fault tolerant system, a failure due to imperfect coverage [13] is less desirable compared with a failure due to the exhaustion of redundancy. Transient probability of system failure is easily broken down into its constituent causes 1 This chapter is based on the paper Conditional MTTF and its Computation in Markov Reliability Models by H. Choi and K. S. ....

....clear that the following relations of MTTFs hold: MTTF S MTTF D MTTF D MTTF DS MTTF S MTTF DS when C DS 0:5. In order for any system to be dependable, the coverage factor of the system should be reasonably high. Most of practical systems have a coverage value bigger than 0. 9 [13, 40]. Considering this 143 fact, we have the following relations hold in most cases: MTTF D MTTF S MTTF DS : 8:21) MTTF of the duplex system is the smallest among the three architectures. It is even worse than the simplex system. This is because the rate of fault occurrence from two ....

W. G. Bouricius, W. C. Carter, and P. R. Schneider. Reliability modeling techniques for self-repairing computer systems. In Proceedings of the 24th Annual ACM National Conference, pages 295--309, 1969.

....factor, and shock models) are surveyed in (Fleming, Mosleh, and Deremer 1986; Hokstad 1993; Modarres 1993) The beta factor is similar in utilization to the coverage parameter, although of distinct origin and slightly different semantics. The coverage parameter c (0 c 1) due to Carter et al. (Bouricius, Carter, and Schneider 1969), is a measure of confidence in the error handling mechanism of a fault tolerant system. Some authors (Goble 1991; Smith 1991) determine the coverage parameter only based on the fault detection process, others (Bouricius, Carter, and Schneider 1969; Dugan and Trivedi 1989; Johnson 1989) prefer to ....

....parameter c (0 c 1) due to Carter et al. Bouricius, Carter, and Schneider 1969) is a measure of confidence in the error handling mechanism of a fault tolerant system. Some authors (Goble 1991; Smith 1991) determine the coverage parameter only based on the fault detection process, others (Bouricius, Carter, and Schneider 1969; Dugan and Trivedi 1989; Johnson 1989) prefer to consider in its determination all sequential phases of a given faulthandling mechanism (e.g. fault detection, fault location, fault containment, and or fault recovery) The coverage parameter then may have at least three distinct interpretations. ....

[Article contains additional citation context not shown here]

Bouricius, W. G., W. C. Carter, and P. R. Schneider (1969). Reliability modeling techniques for self-repairing computer systems. In Proceedings of the 24th Annual ACM Nat. Conf., pp.

....measurements of latency. We conclude by a critical assessment of the proposed estimation technique and a demonstration of its application to practical data sets. Keywords: coverage estimation, latency estimation, fault injection, dependability modeling 1. Introduction The seminal paper [7] first defined coverage as a conditional probability to account for the efficiency of fault tolerance mechanisms. This concept rapidly became widely recognized as a major concern in dependability evaluation studies. Since then, a large amount of work has been devoted to refining the notion of ....

W. G. Bouricius, W. C. Carter and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", in Proc. 24th National Conference, pp.295-309, ACM, 1969.

....another reliability related quantity, safety coverage, which is important for assessing the effectiveness of fault tolerant systems. Safety coverage factor is defined as the conditional probability of successful error detection or recovery, given that a fault has manifested itself in the system[31]. In NVS systems, the safety coverage factor depends on the similarity of errors, the severity of errors, and the efficiency of the recovery mechanisms to cope with such errors. Thus, we need to derive a quantitative definition of it for measurement. Since our main interest here is the analysis of ....

W.G. Bouricius, W.C. Carter, and P.R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems," in Proceedings 24th National Conference of the ACM, pp. 295-383, 1969.

....another reliability related quantity, safety coverage, which is important for assessing the effectiveness of fault tolerant systems. Safety coverage factor is defined as the conditional probability of successful error detection or recovery, given that a fault has manifested itself in the system [28]. In NVS systems, the safety coverage factor depends on the similarity of errors, the severity of errors, and the efficiency of the recovery mechanisms to cope with such errors. Thus, we need to derive a quantitative definition for measurement. Since our main interest here is the analysis of the ....

W.G. Bouricius, W.C. Carter, and P.R. Schneider, "Reliability Modeling Techniques for SelfRepairing Computer Systems," in Proceedings 24th National Conference of the ACM, pp. 295-383, - 1969.

....evaluation, fault injection, fault tolerance, Markov chains I. Introduction The evaluation of a fault tolerant system is a complex task that requires the use of different levels of modeling (axiomatic, empirical and physical models) and related tools [1] A large number of studies (e.g. see [2 4]) have shown the prominence of the efficiency of the fault tolerance algorithms and mechanisms (FTAMs) on the dependability of a wide range of systems and architectures. Determination of the appropriate model for the fault tolerance process and proper estimation of the associated coverage ....

W. G. Bouricius, W. C. Carter and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", in Proc. 24th National Conference, pp.295-309, ACM, 1969.

....of this action model and study the effects of data truncation that are unavoidable in any practical measurements of latency. We conclude by a critical assessment of the proposed estimation technique and a demonstration of its application to practical data sets. 1 Introduction The seminal paper [Bouricius et al. 1969] first defined coverage as a conditional probability to account for the efficiency of fault tolerance mechanisms. This concept rapidly became widely recognized as a major concern in dependability evaluation studies. Since then, a large amount of work has been devoted to refining the notion of ....

W. G. Bouricius, W. C. Carter and P. R. Schneider, "Reliability Modeling Techniques for Self-Repairing Computer Systems", in 24th National Conference, pp.295-309, ACM, 1969.

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W.G. Bouricius, W.C. Carter, and P. Schneider, "Reliability Modeling Techniques for Self Repairing Computer Systems," Proc. 24th Nat'l Conf. the ACM, pp. 295-309, Mar. 1969.

No context found.

W. G. Bouricius, W. C. Carter, and P. Schneider, "Reliability modeling techniques for self repairing computer systems," in In Proceedings of the 24th National Conference of the ACM, March 1969, pp. 295--309.

No context found.

W.G. Bouricius, W.C. Carter, and P.R. Schneider, "Reliability modeling techniques for self-repairing computer systems", in Proceedings of 24th National Conference of ACM, pp. 295-309, 1969.

No context found.

Bouricius, W. G., Carter, W. C., and Schneider, P. R., "Reliability modeling techniques for self-repairing computer systems," in Proceedings of the 24th National Conference, pp. 295--309, ACM, Aug. 1969.

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