Jane C. Blake,
Managing Editor

This issue of the Digital Technical Journal presents papers from three companies -- Cray Research, Raytheon, and Kubota Graphics -- that have developed high-performance systems based on the Alpha AXP 64-bit microprocessor. Also included here are papers about the Alpha AXP chip sets for building PCI-based systems and on the compression technique used in the DLT2000 tape product.

Cray Research, the parallel vector processor and supercomputing pioneer, has developed its first massively parallel processor (MPP) for customers who seek the price/performance advantages of an MPP design. As Kent Koeninger, Mark Furtney, and Martin Walker explain, Cray's MPP uses hundreds of fast commercial microprocessors, in this case Digital's DECchip 21064; whereas a parallel vector processor uses dozens of custom (more expensive) vector processors. Their paper focuses on the CRAY T3D system -- an MPP designed to enable a wide range of applications to sustain performance levels higher than those attained on parallel vector processors. The authors review major system aspects, including the programming model, the 3-D torus interconnect, and the physically distributed, logically shared memory.

For the U.S. military, Raytheon has designed an extended environment, commercial off-the-shelf (E²COTS) computer based on the DECchip 21066/68 AXPvme 64 board. Bob Couranz discusses the characteristics of the E²COTS board that provide the military with cost and performance advantages. He describes how designers addressed the military's reliability requirements, one of which is computer operation in a wide temperature range of -54 degrees C to 85 degrees C. Packaging modifications made by Raytheon include reconfiguration of the module board for conduction cooling as opposed to the convection cooling of the commercial product.

Kubota Graphics' advanced 3D imaging and graphics accelerator is used in Digital's DEC 3000 Alpha AXP workstations and in Kubota's workstations. Ron Levine's paper interweaves a description of the Kubota accelerator product with a tutorial on imaging, graphics, and volume rendering. He begins by distinguishing between imaging and graphics technologies and their relationship to volume rendering methods. He then reviews application areas, such as medical imaging and seismic exploration, and expands on volume rendering techniques. The final section addresses the Kubota implementation, the first desktop-level system to provide interactive volume rendering.

Digital encourages broad industry application of the Alpha AXP family of microprocessors. Sam Nadkarni, Walker Anderson, Lauren Carlson, Dave Kravitz, Mitch Norcross, and Tom Wenners describe the chip sets -- one cost focused and one performance focused -- system designers can use to easily build PCI-based Alpha AXP 21064 systems. The authors also present an overview of the EB64+ evaluation kit. This companion to the chip sets gives designers sample designs and an evaluation platform which allows them to quickly evaluate the cost and performance implications of their design choices.

The state-of-the-art DLT2000 tape drive offers high data throughput, up to 3M bytes/s, and high data capacity, up to 30G bytes (compressed). David Cressman outlines the product issues that drove the DLT2000 development and then details the developers' investigation of the performance impact to the tape drive design of two different data compression algorithms, the Lempel-Ziv algorithm and the Improved Data Recording Capability (IDRC) algorithm. He reviews the tests conducted to measure compression efficiency and data throughput rates. The test results, unexpected by developers, reveal that the design using Lempel-Ziv compression generally achieves higher storage capacity and data throughput rates than the IDRC-based design.