The X window system, version 11

Gettys, James; Karlton, Philip L.; McGregor, Scott

doi:10.1002/spe.4380201404

“…Another technique for display broadcasting is to intercept and distribute graphics as commands are sent from the application to the windowing system. The X Window System [Gettys et al 1990] lends itself to this form of display broadcasting because X defines a graphics protocol that separates an application's display from its process. An Xbased collaboration transparency system can cause the shared application to generate graphics commands to redraw the entire application, even if part of the application is actually obscured by other windows.…”

Section: Flexible Collaboration Transparencymentioning

confidence: 99%

Flexible collaboration transparency

Begole

¹

,

Rosson

²

,

Shaffer

³

1999

ACM Trans. Comput.-Hum. Interact.

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This article presents a critique of conventional collaboration transparency systems, also called "application-sharing" systems, which provide the real-time shared use of legacy single-user applications. We find that conventional collaboration transparency systems are inefficient in their use of network resources and lack support for key groupware principles: concurrent work, relaxed WYSIWIS, and group awareness. Next, we present an alternative approach to implementing collaboration transparency that provides many features previously seen only in collaboration-aware applications. Our approach is based on a replicated architecture where selected single-user interface components are dynamically replaced by multiuser versions. The replacement occurs at run-time and is transparent to the single-user application and its developers. As an instance of this approach, we describe its incorporation into a Java-based collaboration transparency system for serializable, Swing-based Java applications, called Flexible JAMM (Java Applets Made Multiuser). To validate that the flexible collaboration transparency system is truly an improvement over conventional systems, we conducted an empirical study of collaborators performing both tightly and loosely coupled tasks using Flexible JAMM versus a representative conventional collaboration transparency system, Microsoft NetMeeting. Completion times were significantly faster in the loosely coupled task using Flexible JAMM and were not adversely affected in the tightly coupled task. Accuracy was equivalent for both systems. Participants greatly preferred Flexible JAMM.

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“…Despite the higher XPC rate, much of the XPC processing on the sender is overlapped with the actual sending of packets, mitigating some of the Nooks overhead. Nevertheless, on slower processors or faster networks, it may be worthwhile to batch outgoing streaming packets as is done, for example, with network terminal protocols [19].…”

Section: Network Benchmarksmentioning

confidence: 99%

Improving the reliability of commodity operating systems

Swift

¹

,

Bershad

²

,

Levy

³

2003

Proceedings of the Nineteenth ACM Symposium on Operating Systems Principles

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Despite decades of research in extensible operating system technology, extensions such as device drivers remain a significant cause of system failures. In Windows XP, for example, drivers account for 85% of recently reported failures.This article describes Nooks, a reliability subsystem that seeks to greatly enhance operating system (OS) reliability by isolating the OS from driver failures. The Nooks approach is practical: rather than guaranteeing complete fault tolerance through a new (and incompatible) OS or driver architecture, our goal is to prevent the vast majority of driver-caused crashes with little or no change to the existing driver and system code. Nooks isolates drivers within lightweight protection domains inside the kernel address space, where hardware and software prevent them from corrupting the kernel. Nooks also tracks a driver's use of kernel resources to facilitate automatic cleanup during recovery.To prove the viability of our approach, we implemented Nooks in the Linux operating system and used it to fault-isolate several device drivers. Our results show that Nooks offers a substantial increase in the reliability of operating systems, catching and quickly recovering from many faults that would otherwise crash the system. Under a wide range and number of fault conditions, we show that Nooks recovers automatically from 99% of the faults that otherwise cause Linux to crash.While Nooks was designed for drivers, our techniques generalize to other kernel extensions. We demonstrate this by isolating a kernel-mode file system and an in-kernel Internet service. Overall, because Nooks supports existing C-language extensions, runs on a commodity operating system and hardware, and enables automated recovery, it represents a substantial step beyond the specialized architectures and type-safe languages required by previous efforts directed at safe extensibility.

show abstract

“…Despite the higher XPC rate, much of the XPC processing on the sender is overlapped with the actual sending of packets, mitigating some of the Nooks overhead. Nevertheless, on slower processors or faster networks, it may be worthwhile to batch outgoing streaming packets, as is done, for example, with network terminal protocols [Gettys et al 1990]. …”

Section: Network Benchmarksmentioning

confidence: 99%

Improving the reliability of commodity operating systems

Swift

¹

,

Bershad

²

,

Levy

³

2005

ACM Trans. Comput. Syst.

View full text Add to dashboard Cite

Despite decades of research in extensible operating system technology, extensions such as device drivers remain a significant cause of system failures. In Windows XP, for example, drivers account for 85% of recently reported failures.This article describes Nooks, a reliability subsystem that seeks to greatly enhance operating system (OS) reliability by isolating the OS from driver failures. The Nooks approach is practical: rather than guaranteeing complete fault tolerance through a new (and incompatible) OS or driver architecture, our goal is to prevent the vast majority of driver-caused crashes with little or no change to the existing driver and system code. Nooks isolates drivers within lightweight protection domains inside the kernel address space, where hardware and software prevent them from corrupting the kernel. Nooks also tracks a driver's use of kernel resources to facilitate automatic cleanup during recovery.To prove the viability of our approach, we implemented Nooks in the Linux operating system and used it to fault-isolate several device drivers. Our results show that Nooks offers a substantial increase in the reliability of operating systems, catching and quickly recovering from many faults that would otherwise crash the system. Under a wide range and number of fault conditions, we show that Nooks recovers automatically from 99% of the faults that otherwise cause Linux to crash.While Nooks was designed for drivers, our techniques generalize to other kernel extensions. We demonstrate this by isolating a kernel-mode file system and an in-kernel Internet service. Overall, because Nooks supports existing C-language extensions, runs on a commodity operating system and hardware, and enables automated recovery, it represents a substantial step beyond the specialized architectures and type-safe languages required by previous efforts directed at safe extensibility.

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The X window system, version 11

Cited by 19 publications

References 8 publications

Flexible collaboration transparency

Flexible collaboration transparency

Improving the reliability of commodity operating systems

Improving the reliability of commodity operating systems

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