dtj v08-02 1996

This document is Volume 8, Number 2 of the Digital Technical Journal, published in 1996. It features four main articles focusing on advancements in Digital's systems software for the Alpha architecture and OpenVMS operating system:

1. Spiralog Log-Structured File System: This section introduces a new cluster-wide file system integrated with OpenVMS 7.0. Based on log-structured file system (LFS) concepts and an ordered write-back model, Spiralog is designed for high data availability, scalability, and performance, especially for write-intensive operations. A key feature is its fast, application-consistent, online backup system, which is shown to be significantly faster than the traditional Files-11 system. Compatibility with existing Files-11 applications is maintained through an emulation layer and an ordered write-behind cache that protects data integrity.

2. OpenVMS for 64-bit Addressable Virtual Memory: This part details the extension of OpenVMS's 32-bit virtual address space to leverage the Alpha processor's 64-bit addressing capabilities. A primary goal was to ensure binary compatibility for existing 32-bit applications. The design involved an asymmetric division of virtual address space (more to applications, less to kernel) and new approaches to page table residency. The articles also discuss how the DEC C compiler, OpenVMS system services, and the C run-time library were adapted to support mixed 32-bit and 64-bit pointer environments.

3. High-Performance Message Passing for Clusters: This article describes Digital's TruCluster MEMORY CHANNEL Software, which significantly reduces intermachine communication overhead in Alpha clusters. By providing fast, user-level access to the MEMORY CHANNEL network, the system achieves communications latency of less than 10 microseconds. This technology is used to build high-performance message-passing systems, with implementations and optimizations for Parallel Virtual Machine (PVM) and Message Passing Interface (MPI) libraries.

4. Speech Recognition Software: This section focuses on the design of user interfaces for the Digital Speech Recognition Software (DSRS), an application integrated with the UNIX desktop environment for Alpha workstations. DSRS allows users to control applications by spoken commands, converting speech into keystrokes. The project aimed to create an easy-to-learn, intuitive, and powerful productivity tool, addressing challenges in user interface design and integration with the desktop environment.

Overall, the journal highlights Digital's efforts to enhance the performance, scalability, and usability of its Alpha-based systems, particularly through innovations in file systems, memory management, cluster communication, and human-computer interaction.