dtj v03-03 1991

This document is Volume 3, Number 3 of the Digital Technical Journal, published by Digital Equipment Corporation in Summer 1991. It primarily focuses on two key areas: VAXcluster Systems and Network Performance and Adapters.

Key themes and topics covered include:

1. VAXcluster System Enhancements for Availability and Scalability:

   • VMS Volume Shadowing Phase II: A new host-based, distributed data protection technique designed to replace older controller-based shadowing, ensuring data availability and integrity across VAXcluster systems even with device or communication path failures.
   • Application Design in VAXcluster Systems: Guidance for designing high-availability applications by leveraging VAXcluster features like client-server computing, data sharing, and synchronization mechanisms (e.g., VMS lock manager, DECdtm services).
   • New Availability Features for Local Area VAXcluster Systems (LAVC): Introduces VMS version 5.4-3 features such as failover between multiple LAN adapters, improved network delay detection and reduction, and sophisticated failure analysis for enhanced cluster resilience.

2. Design and Performance of Network Adapters:

   • DEC LANcontroller 400 Adapter: Details the design, implementation, and performance of an intelligent Ethernet adapter for Digital's XMI bus, emphasizing its ability to off-load host processing and utilize full Ethernet bandwidth.
   • High-performance FDDI Adapter (DEMFA): Explores the architecture and implementation of Digital's first-generation Fiber Distributed Data Interface (FDDI) adapter, designed to handle FDDI's 100 megabits per second (Mb/s) bandwidth and high packet rates through a pipelined architecture.
   • Performance Analysis of FDDI: Investigates how various configuration and workload parameters, particularly the Target Token Rotation Time (TTRT), affect the performance of FDDI Local Area Networks, providing guidelines for optimization.

Overall, the journal highlights Digital's ongoing efforts to advance its VAXcluster technology and develop high-performance, resilient networking solutions to meet the demands for high data availability and system scalability.