dtj v09-04 1997

This document is Volume 9, Number 4 of the Digital Technical Journal, published in 1997 by Digital Equipment Corporation. The issue focuses on advancements and optimizations for systems utilizing Digital's Alpha microprocessor.

The journal features five main articles:

1. SPIKE Optimizer for Alpha Executables: This article describes Spike, a profile-directed performance tool for optimizing large, call-intensive applications (such as commercial databases, CAD programs, and compilers) on Windows NT. Spike improves instruction cache behavior through code layout and reduces instruction path length via "hot-cold" optimization, leading to performance speedups of up to 33%.
2. Analysis of Memory Access Patterns: This paper introduces an experimental Atom-based tool that helps programmers understand and optimize the memory access patterns of their technical applications (e.g., Fortran programs) on Alpha-based architectures. It generates histograms to identify memory access bottlenecks and analyze the impact of different compiler switches on execution.
3. OpenVMS Alpha VLM (Very Large Memory) Design: This article details the memory management features introduced in OpenVMS Alpha version 7.1 to support very large memory applications (over 4 gigabytes). Key design areas include memory-resident global sections, shared page tables, and a physical memory reservation system, all aimed at improving application scaling, reducing start-up/shut-down times, and optimizing memory utilization for demanding applications like databases.
4. PowerStorm 4DT Graphics Adapter: This paper discusses the high-performance graphics software architecture of Digital's PowerStorm 4DT series graphics adapters for mid-range workstations (Digital UNIX and Windows NT). It highlights how the design leverages the Alpha microprocessor's exceptional floating-point speed for geometry and lighting calculations and utilizes a modified direct-rendering technology to achieve industry-leading OpenGL performance.
5. DART: Fast Application-level Networking via Data-copy Avoidance: This article describes DART, a 622-megabit-per-second network adapter designed to enhance network throughput and reduce system overhead. Its core approach is data-copy avoidance, addressing fundamental memory bandwidth bottlenecks to allow applications to efficiently utilize gigabit-class networks without requiring changes to operating system call semantics.

The journal also includes a section listing recent U.S. Patents issued to Digital Equipment Corporation.