Brian K. Schmidt

The interactive performance of SLIM: a stateless, thin-client architecture

Taking the concept of thin clients to the limit, this paper proposes that desktop machines should just be simple, stateless I/O devices (display, keyboard, mouse, etc.) that access a shared pool of computational resources over a dedicated interconnection fabric --- much in the same way as a buildings telephone services are accessed by a collection of handset devices. The stateless desktop design provides a useful mobility model in which users can transparently resume their work on any desktop console.This paper examines the fundamental premise in this system design that modern, off-the-shelf interconnection technology can support the quality-of-service required by todays graphical and multimedia applications. We devised a methodology for analyzing the interactive performance of modern systems, and we characterized the I/O properties of common, real-life applications (e.g. Netscape, streaming video, and Quake) executing in thin-client environments. We have conducted a series of experiments on the Sun Ray™ 1 implementation of this new system architecture, and our results indicate that it provides an effective means of delivering computational services to a workgroup.We have found that response times over a dedicated network are so low that interactive performance is indistinguishable from a dedicated workstation. A simple pixel encoding protocol requires only modest network resources (as little as a 1Mbps home connection) and is quite competitive with the X protocol. Tens of users running interactive applications can share a processor without any noticeable degradation, and many more can share the network. The simple protocol over a 100Mbps interconnection fabric can support streaming video and Quake at display rates and resolutions which provide a high-fidelity user experience.

An end to end software only scalable video delivery system

Precompressed video delivery systems commonly operate at fixed data rates However, variations in the availability of network bandwidth and processor cycles are common in dynamic general purpose computing environments. Variability arises from the outright lack of resources (e.g. network bandwidth and cpu cycles), contention for available resources due to congestion, or a users unwillingness to allocate needed resources to the task. Users of a scalable video delivery system have greater flexibility and therefore, the system can more effectively deliver video in the presence of system resource scarcity. This paper describes an end-to-end system combining a new scalable video compression algorithm video delivery software, a software video decoder, and a market-based mechanism for the resolution of conflicts in providing video to the user.

A Method and apparatus for measuring media synchronization

Media synchronization is widely regarded as a fundamental problem in the field of multimedia. While much work has been conducted in this area, and many different solutions have been proposed, no method for obtaining a repeatable, objective measure of synchronization performance exists. Thus, there has been no means for determining the effectiveness of potential media synchronization solutions. In this paper we present an experimental methodology for quantitatively measuring the performance of different media synchronization schemes. We describe a complete (hardware and software) test environment for measuring audio/video synchronization quality of various media players, and we also present empirical performance measurements of an example media player. The results show that external observation is necessary for accurate assessments of synchronization performance. This test and evaluation methodology is applicable to other media delivery systems and can serve as the first step in isolating and quantifying the effects of individual components of a media delivery system.