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Reliability models for switches for duplicated computer modules
614
World Abstracts on Microelectronics and Reliability
Assessing component reliability and maintenance schedules for attaining tolerable risks of system-malfunction. J. H. POWELL. Proc. C N E T Conference on Reliability and Maintainability, Tregastel, France, p. 199 (8-12 September 1980). Systematic approaches to the formulation and appraisal of maintenance policies for containing risks of malfunction in industrial and commercial systems are discussed. The relevance of hazard analysis and fault tree analysis techniques to this purpose is briefly considered. Some of the main engineering factors relating to operating conditions and component faults and failures that can influence risks of system-malfunction are examined. The use of theoretical models of reliability/maintenance circumstances to take into account the relative effects of these factors, and to seek trade-offs amongst them, when assessing maintenance policies is illustrated by an example. A two-unit parallel redundant system with bivariate exponential lifetimes. SHUNJI OSAKI. Microelectroll. Reliab. 30, 521 (1980). In this paper we discuss a two-unit parallel redundant system with a single repair facility in which the lifetimes of two units obey a bivariate exponential distribution and the repair time of the failed unit obeys an arbitrary distribution. Applying an extended Markov renewal process, we obtain the quantities of interest thoroughly in reliability theory. Reliability models for switches for duplicated computer modules. WINFRID G. SCHNEEWE1SS. Microelectron. Reliab. 20, 571 (1980). After a short review of existing reliability models for the switching over to a standby component it is shown how to combine these models for the case of duplicated computer modules. Technically speaking this paper contains a derivation of the reliability time function of a lout-of-2-system for a realistic multiplexer model. Reliability block diagrams and "Petri" nets. J. M. JOLLER. Microelectron. Reliab. 20, 613 (1980). A transformation algorithm is given to find a "Petri" net representation corresponding to a reliability block diagram. Several examples are given to illustrate the dynamic character of this representation. As an application we derive probability expressions from the "Petri" net representation. Modelling the repairability function by the first passage time distribution of Brownian motion. Y. S. SHERIF. Microelectron. Reliab. 20, 687 (1980). This paper puts forward the first passage time distribution of Brownian motion as a repairability model. The paper fits the model to observed active repair data of radar systems, obtaining as a result estimates of the mean first passage time, drift and diffusion parameters of the associated Brownian motion. Hypothesizing the first passage time distribution of Brownian motion for active repair time data of radar systems, the Kolmogorov-Smirnov test shows that the model is accepted and can be chosen as the parent population. Replacement models with inspection and preventive maintenance. T. NAKAGAWA.Microelectron. Reliab. 20, 427 (1980). This paper considers the maintenance policy where a unit is inspected and maintained preventively at periodic intervals, and as the effectiveness, the age after maintenance becomes younger. The mean time to failure and the expected number of maintenances before failure are obtained. Two replacement models are considered and an optimum policy for each model is discussed. Test optimization for static RAM memories. M. A. BAIGET and S. PONOMARENKO.Proc. C N E T Cot!ference on Reliability and Maintainability. Tregastel, France, p. 25 (8-12 September 1980). (In French). This paper is a report of a task undertaken at CNES facilities on a C . M O S 4 K x 1 RAM memory. A presentation of functional tests applied on such devices is first described. The relation between the physical
organization and the pinout of addresses is also analysed in order to optimize the tests. These are used in a sequence of environmental tests such as endurance and radiations. Conclusion is done on the basis of results analysis.
Reliability approach of software. J. ALLAIN. Proc. C N E T ConJerence oll Reliability and Maintainability, Treyestel, France, p. 60 (8-12 September 1980). (In French). The growing extent of software through industrial projects justifies this software reliability specification. This document expresses the goals to be reached and the assurance methods to be used on systems where the errors consequences can be catastrophic on the mission processing. The proposed methodology for an industrial application tries to extend already used methods on projects and specially on a space craft system software. Trends to test automation and documentation of PAPE software. JACQUESBOURGEOIS,ANDREBILODEAUand MICHEL POIZE. Proc. C N E T Col!/erence oll Reliability and Maintainability, Treyastel, Fralwe, p. 56 (8-12 September 1980). (In French). The program we present delivers two indicators for complexity and, consequently, reliability of a given software, which could be used as initials measures for models resulting from the extension to software of technics used for hardware. Constituting a step toward the automatization of tests and documentation for PAPE software, this program allows us to study the relation between the complexity of a program and its reliability. Stochastic behaviour of a two-unit paralleled
system.
MAMORU OHASHI, JuN-MING HUANG and TOSHIO NISHIDA. Microelectron. Reliab. 20, 471 (1980). This paper deals with a two-unit paralleled system with a single repair facility. Most papers on this subject assumed that at least one of the life time and repair time distribution is exponential. However, the above assumption is violated by this paper. Then the various state probabilities (densities) have derived by employing the method of supplementary variables. We obtain the stochastic behaviour from these probabilities; (1) the long-run availability, (2) the idleness probability for the repair crew, and (3) the expected number (per unit time in long run) of system failures. Also comparison between the constant failure rate and non-constant failure rate is shown by numerical example.
Optimum policy of one-unit system with two types of maintenance and minimal repair. KOUICHI ADACHI and MASANORI KODAMA. Microelectron. Reliab. 20, 489 (1980). This paper deals with a one-unit system with minimal repair. Two policies (new Policy IV and Policy IV') are considered. Under these policies, the Laplace transform of the point-wise availability and the stationary availability of the system are obtained using not the renewal theory but the supplementary variable method. And under new Policy 1V, the optimum policy in the sense of the availability is discussed. Test and reliability evaluation of microprocessors. C. ROBACH and G. SAUCIER. Proc. C N E T Confi_,rence oll Reliability and Maintainability, Treyastel, France, p. 13 (8-12 September 1980). (In French). A method for the logic testing of isolated microprocessors as well as microprocessor-based systems is proposed. It can be applied either at the end of manufacturing or for the maintenance. A formalized description of a given microprocessor is generated from data given by the user's manual. An ordering of the instructions is done and functional test algorithms, coherent and systematic are generated. In a second part of this paper, a practical test implementation is described. We successively show the structure of a test system and the test program along with the experimental results obtained for the reliability measure of a given microprocessor.
World Abstracts on Microelectronics and Reliability
Assessing component reliability and maintenance schedules for attaining tolerable risks of system-malfunction. J. H. POWELL. Proc. C N E T Conference on Reliability and Maintainability, Tregastel, France, p. 199 (8-12 September 1980). Systematic approaches to the formulation and appraisal of maintenance policies for containing risks of malfunction in industrial and commercial systems are discussed. The relevance of hazard analysis and fault tree analysis techniques to this purpose is briefly considered. Some of the main engineering factors relating to operating conditions and component faults and failures that can influence risks of system-malfunction are examined. The use of theoretical models of reliability/maintenance circumstances to take into account the relative effects of these factors, and to seek trade-offs amongst them, when assessing maintenance policies is illustrated by an example. A two-unit parallel redundant system with bivariate exponential lifetimes. SHUNJI OSAKI. Microelectroll. Reliab. 30, 521 (1980). In this paper we discuss a two-unit parallel redundant system with a single repair facility in which the lifetimes of two units obey a bivariate exponential distribution and the repair time of the failed unit obeys an arbitrary distribution. Applying an extended Markov renewal process, we obtain the quantities of interest thoroughly in reliability theory. Reliability models for switches for duplicated computer modules. WINFRID G. SCHNEEWE1SS. Microelectron. Reliab. 20, 571 (1980). After a short review of existing reliability models for the switching over to a standby component it is shown how to combine these models for the case of duplicated computer modules. Technically speaking this paper contains a derivation of the reliability time function of a lout-of-2-system for a realistic multiplexer model. Reliability block diagrams and "Petri" nets. J. M. JOLLER. Microelectron. Reliab. 20, 613 (1980). A transformation algorithm is given to find a "Petri" net representation corresponding to a reliability block diagram. Several examples are given to illustrate the dynamic character of this representation. As an application we derive probability expressions from the "Petri" net representation. Modelling the repairability function by the first passage time distribution of Brownian motion. Y. S. SHERIF. Microelectron. Reliab. 20, 687 (1980). This paper puts forward the first passage time distribution of Brownian motion as a repairability model. The paper fits the model to observed active repair data of radar systems, obtaining as a result estimates of the mean first passage time, drift and diffusion parameters of the associated Brownian motion. Hypothesizing the first passage time distribution of Brownian motion for active repair time data of radar systems, the Kolmogorov-Smirnov test shows that the model is accepted and can be chosen as the parent population. Replacement models with inspection and preventive maintenance. T. NAKAGAWA.Microelectron. Reliab. 20, 427 (1980). This paper considers the maintenance policy where a unit is inspected and maintained preventively at periodic intervals, and as the effectiveness, the age after maintenance becomes younger. The mean time to failure and the expected number of maintenances before failure are obtained. Two replacement models are considered and an optimum policy for each model is discussed. Test optimization for static RAM memories. M. A. BAIGET and S. PONOMARENKO.Proc. C N E T Cot!ference on Reliability and Maintainability. Tregastel, France, p. 25 (8-12 September 1980). (In French). This paper is a report of a task undertaken at CNES facilities on a C . M O S 4 K x 1 RAM memory. A presentation of functional tests applied on such devices is first described. The relation between the physical
organization and the pinout of addresses is also analysed in order to optimize the tests. These are used in a sequence of environmental tests such as endurance and radiations. Conclusion is done on the basis of results analysis.
Reliability approach of software. J. ALLAIN. Proc. C N E T ConJerence oll Reliability and Maintainability, Treyestel, France, p. 60 (8-12 September 1980). (In French). The growing extent of software through industrial projects justifies this software reliability specification. This document expresses the goals to be reached and the assurance methods to be used on systems where the errors consequences can be catastrophic on the mission processing. The proposed methodology for an industrial application tries to extend already used methods on projects and specially on a space craft system software. Trends to test automation and documentation of PAPE software. JACQUESBOURGEOIS,ANDREBILODEAUand MICHEL POIZE. Proc. C N E T Col!/erence oll Reliability and Maintainability, Treyastel, Fralwe, p. 56 (8-12 September 1980). (In French). The program we present delivers two indicators for complexity and, consequently, reliability of a given software, which could be used as initials measures for models resulting from the extension to software of technics used for hardware. Constituting a step toward the automatization of tests and documentation for PAPE software, this program allows us to study the relation between the complexity of a program and its reliability. Stochastic behaviour of a two-unit paralleled
system.
MAMORU OHASHI, JuN-MING HUANG and TOSHIO NISHIDA. Microelectron. Reliab. 20, 471 (1980). This paper deals with a two-unit paralleled system with a single repair facility. Most papers on this subject assumed that at least one of the life time and repair time distribution is exponential. However, the above assumption is violated by this paper. Then the various state probabilities (densities) have derived by employing the method of supplementary variables. We obtain the stochastic behaviour from these probabilities; (1) the long-run availability, (2) the idleness probability for the repair crew, and (3) the expected number (per unit time in long run) of system failures. Also comparison between the constant failure rate and non-constant failure rate is shown by numerical example.
Optimum policy of one-unit system with two types of maintenance and minimal repair. KOUICHI ADACHI and MASANORI KODAMA. Microelectron. Reliab. 20, 489 (1980). This paper deals with a one-unit system with minimal repair. Two policies (new Policy IV and Policy IV') are considered. Under these policies, the Laplace transform of the point-wise availability and the stationary availability of the system are obtained using not the renewal theory but the supplementary variable method. And under new Policy 1V, the optimum policy in the sense of the availability is discussed. Test and reliability evaluation of microprocessors. C. ROBACH and G. SAUCIER. Proc. C N E T Confi_,rence oll Reliability and Maintainability, Treyastel, France, p. 13 (8-12 September 1980). (In French). A method for the logic testing of isolated microprocessors as well as microprocessor-based systems is proposed. It can be applied either at the end of manufacturing or for the maintenance. A formalized description of a given microprocessor is generated from data given by the user's manual. An ordering of the instructions is done and functional test algorithms, coherent and systematic are generated. In a second part of this paper, a practical test implementation is described. We successively show the structure of a test system and the test program along with the experimental results obtained for the reliability measure of a given microprocessor.