Mobile code technologies such as Java, JavaScript, and ActiveX generally limit all programs to a single restrictive security policy. However, software-based protection can allow for more extensible security models, with potentially significant performance improvements over traditional hardware-based solutions. An extensible security system should be able to protect subsystems and implement policies that are created after the initial system is shipped. We describe and analyze three implementation strategies for interposing such security policies in software-based security systems. Implementations exist for all three strategies: several vendors have adapted capabilities to Java, Netscape and Microsoft have extensions to Java's stack introspection, and we built a name space management system as an add-on to Microsoft Internet Explorer. Theoretically, all these systems are equivalently secure, but many practical issues and implementation details favor some aspects of each system.
诸如Java、JavaScript和ActiveX之类的移动代码技术通常将所有程序限制在单一的限制性安全策略中。然而，基于软件的保护可以支持更多可扩展的安全模型，与传统的基于硬件的解决方案相比，具有潜在的显著性能改进。可扩展的安全系统应该能够保护子系统，并实现在初始系统交付后创建的策略。我们描述并分析了在基于软件的安全系统中插入此类安全策略的三种实现策略。这三种策略的实现都存在:一些供应商已经适应了Java的功能，Netscape和Microsoft对Java的堆栈自省进行了扩展，我们构建了一个名称空间管理系统，作为Microsoft Internet Explorer的附加组件。从理论上讲，所有这些系统都同样安全，但许多实际问题和实现细节有利于每个系统的某些方面。
{"title":"Extensible security architectures for Java","authors":"D. Wallach, D. Balfanz, Drew Dean, E. Felten","doi":"10.1145/268998.266668","DOIUrl":"https://doi.org/10.1145/268998.266668","url":null,"abstract":"Mobile code technologies such as Java, JavaScript, and ActiveX generally limit all programs to a single restrictive security policy. However, software-based protection can allow for more extensible security models, with potentially significant performance improvements over traditional hardware-based solutions. An extensible security system should be able to protect subsystems and implement policies that are created after the initial system is shipped. We describe and analyze three implementation strategies for interposing such security policies in software-based security systems. Implementations exist for all three strategies: several vendors have adapted capabilities to Java, Netscape and Microsoft have extensions to Java's stack introspection, and we built a name space management system as an add-on to Microsoft Internet Explorer. Theoretically, all these systems are equivalently secure, but many practical issues and implementation details favor some aspects of each system.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"31 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114030447","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}
Xiaolan Zhang, Zheng Wang, Nicholas C. Gloy, J. B. Chen, Michael D. Smith
The Morph system provides a framework for automatic collection and management of profile information and application of profile-driven optimizations. In this paper, we focus on the operating system support that is required to collect and manage profile information on an end-user's workstation in an automatic, continuous, and transparent manner. Our implementation for a Digital Alpha machine running Digital UNIX 4.0 achieves run-time overheads of less than 0.3% during profile collection. Through the application of three code layout optimizations, we further show that Morph can use statistical profiles to improve application performance. With appropriate system support, automatic profiling and optimization is both possible and effective.
{"title":"System support for automatic profiling and optimization","authors":"Xiaolan Zhang, Zheng Wang, Nicholas C. Gloy, J. B. Chen, Michael D. Smith","doi":"10.1145/268998.266640","DOIUrl":"https://doi.org/10.1145/268998.266640","url":null,"abstract":"The Morph system provides a framework for automatic collection and management of profile information and application of profile-driven optimizations. In this paper, we focus on the operating system support that is required to collect and manage profile information on an end-user's workstation in an automatic, continuous, and transparent manner. Our implementation for a Digital Alpha machine running Digital UNIX 4.0 achieves run-time overheads of less than 0.3% during profile collection. Through the application of three code layout optimizations, we further show that Morph can use statistical profiles to improve application performance. With appropriate system support, automatic profiling and optimization is both possible and effective.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127971655","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}
The ideal distributed file system would provide all its users with coherent, shared access to the same set of files, yet would be arbitrarily scalable to provide more storage space and higher performance to a growing user community. It would be highly available in spite of component failures. It would require minimal human administration, and administration would not become more complex as more components were added. Frangipani is a new file system that approximates this ideal, yet was relatively easy to build because of its two-layer structure. The lower layer is Petal (described in an earlier paper), a distributed storage service that provides incrementally scalable, highly available, automatically managed virtual disks. In the upper layer, multiple machines run the same Frangipani file system code on top of a shared Petal virtual disk, using a distributed lock service to ensure coherence. Frangipani is meant to run in a cluster of machines that are under a common administration and can communicate securely. Thus the machines trust one another and the shared virtual disk approach is practical. Of course, a Frangipani file system can be exported to untrusted machines using ordinary network file access protocols. We have implemented Frangipani on a collection of Alphas running DIGITAL Unix 4.0. Initial measurements indicate that Frangipani has excellent single-server performance and scales well as servers are added.
{"title":"Frangipani: a scalable distributed file system","authors":"C. Thekkath, T. Mann, Edward K. F. Lee","doi":"10.1145/268998.266694","DOIUrl":"https://doi.org/10.1145/268998.266694","url":null,"abstract":"The ideal distributed file system would provide all its users with coherent, shared access to the same set of files, yet would be arbitrarily scalable to provide more storage space and higher performance to a growing user community. It would be highly available in spite of component failures. It would require minimal human administration, and administration would not become more complex as more components were added. Frangipani is a new file system that approximates this ideal, yet was relatively easy to build because of its two-layer structure. The lower layer is Petal (described in an earlier paper), a distributed storage service that provides incrementally scalable, highly available, automatically managed virtual disks. In the upper layer, multiple machines run the same Frangipani file system code on top of a shared Petal virtual disk, using a distributed lock service to ensure coherence. Frangipani is meant to run in a cluster of machines that are under a common administration and can communicate securely. Thus the machines trust one another and the shared virtual disk approach is practical. Of course, a Frangipani file system can be exported to untrusted machines using ordinary network file access protocols. We have implemented Frangipani on a collection of Alphas running DIGITAL Unix 4.0. Initial measurements indicate that Frangipani has excellent single-server performance and scales well as servers are added.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131706950","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}
This paper presents HAC, a novel technique for managing the client cache in a distributed, persistent object storage system. HAC is a hybrid between page and object caching that combines the virtues of both while avoiding their disadvantages. It achieves the low miss penalties of a page-caching system, but is able to perform well even when locality is poor, since it can discard pages while retaining their hot objects. It realizes the potentially lower miss rates of object-caching systems, yet avoids their problems of fragmentation and high overheads. Furthermore, HAC is adaptive: when locality is good it behaves like a page-caching system, while if locality is poor it behaves like an object-caching system. It is able to adjust the amount of cache space devoted to pages dynamically so that space in the cache can be used in the way that best matches the needs of the application. The paper also presents results of experiments that indicate that HAC outperforms other object storage systems across a wide range of cache sizes and workloads; it performs substantially better on the expected workloads, which have low to moderate locality. Thus we show that our hybrid, adaptive approach is the cache management technique of choice for distributed, persistent object systems.
{"title":"HAC: hybrid adaptive caching for distributed storage systems","authors":"M. Castro, A. Adya, B. Liskov, A. Myers","doi":"10.1145/268998.266666","DOIUrl":"https://doi.org/10.1145/268998.266666","url":null,"abstract":"This paper presents HAC, a novel technique for managing the client cache in a distributed, persistent object storage system. HAC is a hybrid between page and object caching that combines the virtues of both while avoiding their disadvantages. It achieves the low miss penalties of a page-caching system, but is able to perform well even when locality is poor, since it can discard pages while retaining their hot objects. It realizes the potentially lower miss rates of object-caching systems, yet avoids their problems of fragmentation and high overheads. Furthermore, HAC is adaptive: when locality is good it behaves like a page-caching system, while if locality is poor it behaves like an object-caching system. It is able to adjust the amount of cache space devoted to pages dynamically so that space in the cache can be used in the way that best matches the needs of the application. The paper also presents results of experiments that indicate that HAC outperforms other object storage systems across a wide range of cache sizes and workloads; it performs substantially better on the expected workloads, which have low to moderate locality. Thus we show that our hybrid, adaptive approach is the cache management technique of choice for distributed, persistent object systems.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134334400","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}
In this paper we examine the problem of extending modern operating systems to run efficiently on large-scale shared memory multiprocessors without a large implementation effort. Our approach brings back an idea popular in the 1970s, virtual machine monitors. We use virtual machines to run multiple commodity operating systems on a scalable multiprocessor. This solution addresses many of the challenges facing the system software for these machines. We demonstrate our approach with a prototype called Disco that can run multiple copies of Silicon Graphics' IRIX operating system on a multiprocessor. Our experience shows that the overheads of the monitor are small and that the approach provides scalability as well as the ability to deal with the non-uniform memory access time of these systems. To reduce the memory overheads associated with running multiple operating systems, we have developed techniques where the virtual machines transparently share major data structures such as the program code and the file system buffer cache. We use the distributed system support of modern operating systems to export a partial single system image to the users. The overall solution achieves most of the benefits of operating systems customized for scalable multiprocessors yet it can be achieved with a significantly smaller implementation effort.
{"title":"Disco: running commodity operating systems on scalable multiprocessors","authors":"Edouard Bugnion, Scott Devine, M. Rosenblum","doi":"10.1145/268998.266672","DOIUrl":"https://doi.org/10.1145/268998.266672","url":null,"abstract":"In this paper we examine the problem of extending modern operating systems to run efficiently on large-scale shared memory multiprocessors without a large implementation effort. Our approach brings back an idea popular in the 1970s, virtual machine monitors. We use virtual machines to run multiple commodity operating systems on a scalable multiprocessor. This solution addresses many of the challenges facing the system software for these machines. We demonstrate our approach with a prototype called Disco that can run multiple copies of Silicon Graphics' IRIX operating system on a multiprocessor. Our experience shows that the overheads of the monitor are small and that the approach provides scalability as well as the ability to deal with the non-uniform memory access time of these systems. To reduce the memory overheads associated with running multiple operating systems, we have developed techniques where the virtual machines transparently share major data structures such as the program code and the file system buffer cache. We use the distributed system support of modern operating systems to export a partial single system image to the users. The overall solution achieves most of the benefits of operating systems customized for scalable multiprocessors yet it can be achieved with a significantly smaller implementation effort.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125579177","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}
B. Ford, Godmar Back, Gregory D. Benson, Jay Lepreau, A. Lin, O. Shivers
Implementing new operating systems is tedious, costly, and often impractical except for large projects. The Flux OSKit addresses this problem in a novel way by providing clean, well-documented OS components designed to be reused in a wide variety of other environments, rather than defining a new OS structure. The OSKit uses unconventional techniques to maximize its usefulness, such as intentionally exposing implementation details and platform-specific facilities. Further, the OSKit demonstrates a technique that allows unmodified code from existing mature operating systems to beincorporated quickly and updated regularly, by wrapping it with a small amount of carefully designed “glue” code to isolate it s dependencies and export well-defined interfaces. The OSKit uses this technique to incorporate over 230,000 lines of stable code including device drivers, file systems, and network protocols. Ourexperience demonstrates that this approach to component software structure and reuse has a surprisingly large impact in the OS implementation domain. Four real-world examples show how the OSKit is catalyzing research and development in operating systems and programming languages.
{"title":"The Flux OSKit: a substrate for kernel and language research","authors":"B. Ford, Godmar Back, Gregory D. Benson, Jay Lepreau, A. Lin, O. Shivers","doi":"10.1145/268998.266642","DOIUrl":"https://doi.org/10.1145/268998.266642","url":null,"abstract":"Implementing new operating systems is tedious, costly, and often impractical except for large projects. The Flux OSKit addresses this problem in a novel way by providing clean, well-documented OS components designed to be reused in a wide variety of other environments, rather than defining a new OS structure. The OSKit uses unconventional techniques to maximize its usefulness, such as intentionally exposing implementation details and platform-specific facilities. Further, the OSKit demonstrates a technique that allows unmodified code from existing mature operating systems to beincorporated quickly and updated regularly, by wrapping it with a small amount of carefully designed “glue” code to isolate it s dependencies and export well-defined interfaces. The OSKit uses this technique to incorporate over 230,000 lines of stable code including device drivers, file systems, and network protocols. Ourexperience demonstrates that this approach to component software structure and reuse has a surprisingly large impact in the OS implementation domain. Four real-world examples show how the OSKit is catalyzing research and development in operating systems and programming languages.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128632606","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}
Real-time applications such as multimedia audio and video are increasingly populating the workstation desktop. To support the execution of these applications in conjunction with traditional non-realtime applications, we have created SMART, a Scheduler for Multimedia And Real-Time applications. SMART supports applications with time constraints, and provides dynamic feedback to applications to allow them to adapt to the current load. In addition, the support for real-time applications is inte grated with the support for conventional computations. This allows the user to prioritize across real-time and conventional computations, and dictate how the processor is to be shared among applications of the same priority . As the system load changes, SMART adjusts the allocation of resources dynamically and seamlessly. SMAR T is unique in its ability to automatically shed real-time tasks and re gulate their execution rates when the system is overloaded, while providing better value in underloaded conditions than previously proposed schemes. We have implemented SMART in the Solaris UNIX operating system and measured its performance against other schedulers in e xecuting real-time, interacti ve, and batch applications. Our results demonstrate SMART’s superior performance in supporting multimedia applications.
{"title":"The design, implementation and evaluation of SMART: a scheduler for multimedia applications","authors":"Jason Nieh, M. Lam","doi":"10.1145/268998.266677","DOIUrl":"https://doi.org/10.1145/268998.266677","url":null,"abstract":"Real-time applications such as multimedia audio and video are increasingly populating the workstation desktop. To support the execution of these applications in conjunction with traditional non-realtime applications, we have created SMART, a Scheduler for Multimedia And Real-Time applications. SMART supports applications with time constraints, and provides dynamic feedback to applications to allow them to adapt to the current load. In addition, the support for real-time applications is inte grated with the support for conventional computations. This allows the user to prioritize across real-time and conventional computations, and dictate how the processor is to be shared among applications of the same priority . As the system load changes, SMART adjusts the allocation of resources dynamically and seamlessly. SMAR T is unique in its ability to automatically shed real-time tasks and re gulate their execution rates when the system is overloaded, while providing better value in underloaded conditions than previously proposed schemes. We have implemented SMART in the Solaris UNIX operating system and measured its performance against other schedulers in e xecuting real-time, interacti ve, and batch applications. Our results demonstrate SMART’s superior performance in supporting multimedia applications.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128566498","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}
Hermann Härtig, Michael Hohmuth, J. Liedtke, S. Schönberg, J. Wolter
First-generation μ-kernels have a reputation for being too slow and lacking sufficient flexibility. To determine whether L4, a lean second-generation μ-kernel, has overcome these limitations, we have repeated several earlier experiments and conducted some novel ones. Moreover, we ported the Linux operating system to run on top of the L4 μ-kernel and compared the resulting system with both Linux running native, and MkLinux, a Linux version that executes on top of a first-generation Mach-derived μ-kernel. For L 4 Linux, the AIM benchmarks report a maximum throughput which is only 5% lower than that of native Linux. The corresponding penalty is 5 times higher for a co-located in-kernel version of MkLinux, and 7 times higher for a user-level version of MkLinux. These numbers demonstrate both that it is possible to implement a high-performance conventional operating system personality above a μ-kernel, and that the performance of the μ-kernel is crucial to achieve this. Further experiments illustrate that the resulting system is highly extensible and that the extensions perform well. Even real-time memory management including second-level cache allocation can be implemented at user-level, coexisting with L 4 Linux.
{"title":"The performance of μ-kernel-based systems","authors":"Hermann Härtig, Michael Hohmuth, J. Liedtke, S. Schönberg, J. Wolter","doi":"10.1145/268998.266660","DOIUrl":"https://doi.org/10.1145/268998.266660","url":null,"abstract":"First-generation μ-kernels have a reputation for being too slow and lacking sufficient flexibility. To determine whether L4, a lean second-generation μ-kernel, has overcome these limitations, we have repeated several earlier experiments and conducted some novel ones. Moreover, we ported the Linux operating system to run on top of the L4 μ-kernel and compared the resulting system with both Linux running native, and MkLinux, a Linux version that executes on top of a first-generation Mach-derived μ-kernel. For L 4 Linux, the AIM benchmarks report a maximum throughput which is only 5% lower than that of native Linux. The corresponding penalty is 5 times higher for a co-located in-kernel version of MkLinux, and 7 times higher for a user-level version of MkLinux. These numbers demonstrate both that it is possible to implement a high-performance conventional operating system personality above a μ-kernel, and that the performance of the μ-kernel is crucial to achieve this. Further experiments illustrate that the resulting system is highly extensible and that the extensions perform well. Even real-time memory management including second-level cache allocation can be implemented at user-level, coexisting with L 4 Linux.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133576301","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}
S. Savage, M. Burrows, Greg Nelson, P. Sobalvarro, T. Anderson
{"title":"Eraser: a dynamic data race detector for multi-threaded programs","authors":"S. Savage, M. Burrows, Greg Nelson, P. Sobalvarro, T. Anderson","doi":"10.1145/268998.266641","DOIUrl":"https://doi.org/10.1145/268998.266641","url":null,"abstract":"","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121477927","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}
Tiger is a scalable, fault-tolerant video file server constructed from a collection of computers connected by a switched network. All content files are striped across all of the computers and disks in a Tiger system. In order to prevent conflicts for a particular resource between two viewers, Tiger schedules viewers so that they do not require access to the same resource at the same time. In the abstract, there is a single, global schedule that describes all of the viewers in the system. In practice, the schedule is distributed among all of the computers in the system, each of which has a possibly partially inconsistent view of a subset of the schedule. By using such a relaxed consistency model for the schedule, Tiger achieves scalability and fault tolerance while still providing the consistent, coordinated service required by viewers.
{"title":"Distributed schedule management in the Tiger video fileserver","authors":"W. Bolosky, Robert P. Fitzgerald, John R. Douceur","doi":"10.1145/268998.266692","DOIUrl":"https://doi.org/10.1145/268998.266692","url":null,"abstract":"Tiger is a scalable, fault-tolerant video file server constructed from a collection of computers connected by a switched network. All content files are striped across all of the computers and disks in a Tiger system. In order to prevent conflicts for a particular resource between two viewers, Tiger schedules viewers so that they do not require access to the same resource at the same time. In the abstract, there is a single, global schedule that describes all of the viewers in the system. In practice, the schedule is distributed among all of the computers in the system, each of which has a possibly partially inconsistent view of a subset of the schedule. By using such a relaxed consistency model for the schedule, Tiger achieves scalability and fault tolerance while still providing the consistent, coordinated service required by viewers.","PeriodicalId":340271,"journal":{"name":"Proceedings of the sixteenth ACM symposium on Operating systems principles","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1997-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115033518","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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