A Component-based Framework for Uniform Resource Visualization

The PGRT project has prototyped a framework for integrating performance analysis tools for parallel and distributed systems and for visualizing system and application performance [7]. One result of PGRT is a component-based specification language called the Visual Object Markup Language (VOML) [4][5][6]. VOML is an SGML-based language for specifying on-line performance visualization components. The framework includes two key features that support an integrated environment for performance problem solving: (1) portability across platformdependent user interface toolkits, and (2) a flexible component-based visualization architecture, EPIRA (Event Processing and Information Rendering Architecture). Furthermore, the framework is object-oriented and easily distributable via middleware software such as CORBA and DCOM. VOML is based on two visual-object levels: a device-dependent low level, and a deviceindependent high-level. VOML uses SGML for structuring visual objects, and Scheme language scripts for defining performance visualization semantics. The use of SGML enables development of a performance visualization infrastructure, from which a designer may construct platformand tool-independent visual objects. It may also facilitate automatic monitoring, analysis, and visualization of wide-area distributed applications via network-enabled SGML entity managers. The use of Scheme for visual object semantics enables both rapid prototyping of visual objects and customizing of VOs for a wide range of platforms.