Shared window systems enable existing applications to be shared in the context of a real-time teleconference. The development and successful use of several such systems, albeit within limited user communities, testifies to the merits of the basic idea. However, experience to date has suggested a number of areas that have not been adequately addressed, namely: spontaneous interactions, shared workspace management, floor control, and annotation and telepointing. This paper focuses on the ramifications, for the software designer, of various user requirements in these areas. While the recommendations that result are motivated by the desire to enable continued use of collaboration-transparent applications, addressing them involves the development of systems software that is distinctly collaboration-aware.

The authors describe the design and performance of scheduling facilities for finding idle hosts in a workstation-based distributed system. They focus on the tradeoffs between centralized and decentralized architectures with respect to scalability, fault tolerance, and simplicity of design, as well as several implementation issues of interest when multicast communication is used. They conclude that the principal tradeoff between the two approaches is that a centralized architecture can be scaled to a significantly greater degree and can more easily monitor global system statistics whereas a decentralized architecture is simpler to implement.>

The design and performance of scheduling facilities for finding idle hosts in a workstation-based distributed system are described. The focus is on the tradeoffs between centralized and decentralized architectures with respect to scalability, fault tolerance, and simplicity of design, as well as several implementation issues of interest when using multicast communication. It is concluded that the principal tradeoff between the two approaches is that a centralized architecture can be scaled to a significantly greater degree and can more easily monitor global system statistics, while a decentralized architecture is simpler to implement.>

The subject of User Interface Management Systems (UIMS) has been a topic of research and debate for the last several years. The goal of such systems has been to automate the production of user interface software. The problem of building quality user interfaces within available resources is a very important one as the demand for new interactive programs grows. Prototype UIMSs have been built and some software packages are presently being marketed as such. Many papers have been published on the topic.

This paper deals with the integration of multimedia conferencing facilities into an existing software environment. We assume that the "semantics" of the conferencing facilities have already been defined and address only the issue of how to implement those semantics in such a way as to minimize the impact on existing software. In particular, users should be able to invoke any application from within the framework of a conference, and programmers should be able to develop new applications without having to deal explicitly with conferencing issues. We present the basic architectural approachs to this problem and discuss an early experiment with one of them.

Article Towards a universal directory service Share on Authors: Keith A. Lantz Computer Systems Laboratory, Departments of Computer Science and Electrical Engineering, Stanford University, Stanford, CA Computer Systems Laboratory, Departments of Computer Science and Electrical Engineering, Stanford University, Stanford, CAView Profile , Judy L. Edighoffer Computer Systems Laboratory, Departments of Computer Science and Electrical Engineering, Stanford University, Stanford, CA Computer Systems Laboratory, Departments of Computer Science and Electrical Engineering, Stanford University, Stanford, CAView Profile , Bruce L. Hitson Computer Systems Laboratory, Departments of Computer Science and Electrical Engineering, Stanford University, Stanford, CA Computer Systems Laboratory, Departments of Computer Science and Electrical Engineering, Stanford University, Stanford, CAView Profile Authors Info & Claims PODC '85: Proceedings of the fourth annual ACM symposium on Principles of distributed computingAugust 1985 Pages 250–260https://doi.org/10.1145/323596.323619Online:01 August 1985Publication History 19citation220DownloadsMetricsTotal Citations19Total Downloads220Last 12 Months0Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

Article Free Access Share on Preemptable remote execution facilities for the V-system Authors: Marvin M. Theimer Computer Science Department, Stanford University, Stanford, CA Computer Science Department, Stanford University, Stanford, CAView Profile , Keith A. Lantz Computer Science Department, Stanford University, Stanford, CA Computer Science Department, Stanford University, Stanford, CAView Profile , David R. Cheriton Computer Science Department, Stanford University, Stanford, CA Computer Science Department, Stanford University, Stanford, CAView Profile Authors Info & Claims SOSP '85: Proceedings of the tenth ACM symposium on Operating systems principlesDecember 1985 Pages 2–12https://doi.org/10.1145/323647.323629Published:01 December 1985Publication History 227citation736DownloadsMetricsTotal Citations227Total Downloads736Last 12 Months33Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

A major reason for the rarity of distributed applications, despite the proliferation of networks, is the sensitivity of their performance to various aspects of the network environment. We demonstrate that distributed applications can run faster than local ones, using common hardware. We also show that the primary factors affecting performance are, in approximate order of importance: speed of the user's workstation, speed of the remote host (if any), and the high-level (above the transport level) protocols used. In particular, the use of batching, pipelining, and structure in high-level protocols reduces the degradation often experienced between different bandwidth networks. Less significant, but still noticeable improvements result from proper design and implementation of the underlying transport protocols. Ultimately, with proper application of these techniques, network bandwidth is rendered virtually insignificant.

Abstract We describe the operating system Perseus, developed as part of a study into the issues of computer communications and their impact on operating system and programming language design. Perseus was designed to be portable by virtue of its kernel‐based structure and its implementation in Pascal. In particular, machine‐dependent code is limited to the kernel and most operating systems functions are provided by server processes, running in user mode. Perseus was designed to evolve into a distributed operating system by virtue of its interprocess communication facilities, based on message‐passing. This paper presents an overview of the system and gives an assessment of how far it satisfied its original goals. Specifically, we evaluate its interprocess communication facilities and kernel‐based structure, and discuss its portability. We close with a brief history of the project, pointing out major milestones and stumbling blocks.

One of the most important functions of an intelligent workstation is to provide a state-of-the-art user interface to distributed resources.One aspect of such an interface is virtual terminal support for both local and remote applications with a range of requirements, including graphics.To ensure good response for remote applications, in particular, the bulk of user interaction must be handled local to the workstation.Therefore, the terminal management software on the workstation must provide object modeling as well as viewing facilities, in contrast to most contemporary graphics systems.One way of doing this is to support structured display files.It is equally important to support simultaneous access to multiple applications; thus the terminal management software must provide window system Lscilities.Lastly, since the terminal management software should present a common interface to both local and remote applications, the workstation itself should be regarded as a multifunction component of the distributed system and not strictly as a terminal or a personal computer.This paper presents the system architecture and protocols necessary to achieve these goals and evaluates an existing implementation.

Rochester's Intelligent Gateway provides its users with the facilities for communicating simultaneously with a large number of processes spread out among various computer systems. We have adopted the philosophy that the user should be able to manage any number of concurrent tasks or jobs, viewing their output on his display device as he desires. To achieve this goal the Virtual Terminal Management System (VTMS) converts a single physical terminal into multiple virtual terminals, each of which may be written to or queried for user input. VTMS extends the features of the physical terminal by providing extensive editing facilities, the capacity to maintain all output In disk-based data structures, and sophisticated mechanisms for the management of screen space. Virtual terminals are device-independent; the specific characteristics of the physical terminal are known only to the lowest-level I/O handlers for that device. VTMS Is currently running on a network of six minicomputers supporting various text and raster-graphics displays.