Integrating Segmentation and Paging Protection for Safe, Efficient and Transparent Software Extensions

The technological evolution towards extensible software architectures and component-based software development demands safe, efficient, flexible, and easy-touse extension mechanisms to provide protection among software modules residing in the same address space. While a number of software-based approaches have been proposed in the last several years, no clear winner emerges that satisfactorily addresses all the design issues involved in establishing multiple protection domains within an address space. This paper describes the design, implementation, and evaluation of a novel intra-address space protection mechanism called Palladium, which is built upon the combined segmentation and paging protection hardware provided by Intel's X86 architecture. Based on the considerations on application programming and systems implementation complexity, we chose to use slightly different approaches to implement the user-level and kernel-level extension mechanisms. To demonstrate the resulting prototyp..

Cube-3: A Real-Time Architecture for High-Resolution Volume Visualization

This paper describes a high-performance special-purpose system, Cube-3, for displaying and manipulating high- resolution volumetric datasets in real-time. A primary goal of Cube-3 is to render 512^3, 16-bit per voxel, datasets at about 30 frames per second. Cube-3 implements a ray-casting algorithm in a highly-parallel and pipelined architecture, using a 3D skewed volume memory, a modular fast bus, 2D skewed bu ffers, 3D interpolation and shading units, and a ray projection cone. Cube-3 will allow users to interactively visualize and investigate in real-time static (3D) and dynamic (4D) high-resolution volumetric datasets.Engineering and Applied Science