Pub Date : 1995-02-01DOI: 10.1109/RELDIS.1995.518718
D. Long, A. Muir, Richard A. Golding
An accurate estimate of host reliability is important for correct analysis of many fault-tolerance and replication mechanisms. In a previous study, we estimated host system reliability by querying a large number of hosts to find how long they had been functioning, estimating the mean time-to-failure (MTTF) and availability from those measures, and in turn deriving an estimate of the mean time-to-repair (MTTR). However, this approach had a bias towards more reliable hosts that could result in overestimating MTTR and underestimating availability. To address this bias we have conducted a second experiment using a fault-tolerant replicated monitoring tool. This tool directly measures TTF, TTR, and availability by polling many sites frequently from several locations. We find that these more accurate results generally confirm and improve our earlier estimates, particularly for TTR. We also find that failure and repair are unlikely to follow Poisson processes.
{"title":"A longitudinal survey of Internet host reliability","authors":"D. Long, A. Muir, Richard A. Golding","doi":"10.1109/RELDIS.1995.518718","DOIUrl":"https://doi.org/10.1109/RELDIS.1995.518718","url":null,"abstract":"An accurate estimate of host reliability is important for correct analysis of many fault-tolerance and replication mechanisms. In a previous study, we estimated host system reliability by querying a large number of hosts to find how long they had been functioning, estimating the mean time-to-failure (MTTF) and availability from those measures, and in turn deriving an estimate of the mean time-to-repair (MTTR). However, this approach had a bias towards more reliable hosts that could result in overestimating MTTR and underestimating availability. To address this bias we have conducted a second experiment using a fault-tolerant replicated monitoring tool. This tool directly measures TTF, TTR, and availability by polling many sites frequently from several locations. We find that these more accurate results generally confirm and improve our earlier estimates, particularly for TTR. We also find that failure and repair are unlikely to follow Poisson processes.","PeriodicalId":275219,"journal":{"name":"Proceedings. 14th Symposium on Reliable Distributed Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126541911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1994-09-06DOI: 10.1109/RELDIS.1995.526224
J. Gall, François Simon
Satellite payloads of the near future will raise the need of very powerful and dependable computers. No embeddable monoprocessor will be able to satisfy such computing power need. Thus those computers will be multi-processor systems. Satellite payloads must meet high availability requirements rather then reliability ones. This allows the use of fail stop reconfigurable computers. This paper describes the MUSE architecture, a reconfigurable multi-processor computer designed to support signal processing applications in space systems.
{"title":"MUSE: a message passing concurrent computer for on-board space systems","authors":"J. Gall, François Simon","doi":"10.1109/RELDIS.1995.526224","DOIUrl":"https://doi.org/10.1109/RELDIS.1995.526224","url":null,"abstract":"Satellite payloads of the near future will raise the need of very powerful and dependable computers. No embeddable monoprocessor will be able to satisfy such computing power need. Thus those computers will be multi-processor systems. Satellite payloads must meet high availability requirements rather then reliability ones. This allows the use of fail stop reconfigurable computers. This paper describes the MUSE architecture, a reconfigurable multi-processor computer designed to support signal processing applications in space systems.","PeriodicalId":275219,"journal":{"name":"Proceedings. 14th Symposium on Reliable Distributed Systems","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123436721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.1109/RELDIS.1995.526221
W.E. Kuhnhauser
One of today's major challenges in computer security is the ever-increasing multitude of individual, application-specific security requirements. As a positive consequence, a wide variety of security policies has been developed, each policy reflecting the specific needs of individual applications. As a negative consequence, the integration of the multitude of policies into today's system platforms made the limitations of traditional architectural foundations of secure computer systems quite obvious. Many of the traditional architectural foundations originally aimed at supporting only a single access control policy within a single trusted system environment. This paper discusses a new paradigm to support user-defined security policies in a distributed multi-policy system. The paradigm preserves the successful properties of the traditional architectural foundations while additionally providing strong concepts for user-defined security policies. Among these concepts are policy separation, encapsulation, persistency, cooperation, and reusability. We illustrate the application of our approach in a DCE environment.
{"title":"A paradigm for user-defined security policies","authors":"W.E. Kuhnhauser","doi":"10.1109/RELDIS.1995.526221","DOIUrl":"https://doi.org/10.1109/RELDIS.1995.526221","url":null,"abstract":"One of today's major challenges in computer security is the ever-increasing multitude of individual, application-specific security requirements. As a positive consequence, a wide variety of security policies has been developed, each policy reflecting the specific needs of individual applications. As a negative consequence, the integration of the multitude of policies into today's system platforms made the limitations of traditional architectural foundations of secure computer systems quite obvious. Many of the traditional architectural foundations originally aimed at supporting only a single access control policy within a single trusted system environment. This paper discusses a new paradigm to support user-defined security policies in a distributed multi-policy system. The paradigm preserves the successful properties of the traditional architectural foundations while additionally providing strong concepts for user-defined security policies. Among these concepts are policy separation, encapsulation, persistency, cooperation, and reusability. We illustrate the application of our approach in a DCE environment.","PeriodicalId":275219,"journal":{"name":"Proceedings. 14th Symposium on Reliable Distributed Systems","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121713812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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