Object Placement in Parallel Hypermedia Systems

并行超媒体系统中的对象放置这是一项为期三年的持续拨款的第一年。多媒体信息系统已经成为从数字图书馆到娱乐技术等许多应用领域的重要组成部分。然而，这些系统的大多数实现不能支持多媒体对象的连续显示，并且经常遭受称为打嗝的中断。这是由于这些对象的大尺寸要求它们几乎总是驻留在磁盘上，并且当前磁盘技术的低I/O带宽与多媒体对象的高带宽需求之间存在差异。为了解决这个限制，将多媒体对象分散到多个磁盘驱动器上，使系统能够利用多个磁盘的聚合带宽来支持其连续检索。此外，正在开发虚拟数据复制作为一种机制，以支持同时向不同用户显示多个对象。本项目研究以下技术：(1)提供对大量多媒体数据的在线访问；(2)通过预取数据使系统响应时间最小化；(3)通过优化对象跨处理器的位置，使系统的处理能力最大化。这项研究的结果有望为开发可扩展到数千个处理器的高性能多媒体信息系统提供基础。＊＊＊

9203389 Ghandeharizadeh Object-Placement in Parallel Hypermedia Systems This is the first year funding of a three-year continuing award. Multimedia information systems have emerged as an essential component of many application domains ranging from digital libraries to entertainment technology. However, most implementations of these systems cannot support a continuous display of multimedia objects and suffer from frequent disruptions termed hiccups . This is due to the large size of these objects that requires them to be almost always disk resident, and the disparity between the low I/O bandwidth of the current disk technology and the high bandwidth requirement of multimedia objects. To resolve this limitation, a multimedia object is declustered across multiple disk drives, enabling the system to utilize the aggregate bandwidth of multiple disks to support its continuous retrieval. Moreover, virtual data replication is being developed as a mechanism to support simultaneous display of several objects to different users. This project investigates techniques that: (1) provide on-line access to vast amount of multimedia data; (2) minimize the response time of the system by prefetching data; and (3) maximize the processing capability of the system by optimizing the placement of the objects across the processors. The results of this research are expected to provide a foundation for the development of high performance multimedia information systems that can scale to thousands of processors. ***