The Development of an Optimized PATHWORKS Transport Interface

This document from the Digital Technical Journal (Winter 1992) details the efforts of the Personal Computing Systems Group to optimize the PATHWORKS for VMS version 4.0 server.

Key points include:

• Problem: The standard buffered interface caused significant CPU overhead, especially with small request sizes, degrading performance.
• Solution: The engineering team implemented the local area system transport (LAST) protocol and developed a new double-mapped buffering algorithm using shared queues.
• Optimizations:
  • Utilized a 'transceive' operation to reduce system boundary crossings.
  • Implemented a buffer management protocol (BMP) layer to handle buffering and request/response integrity.
• Results: Benchmark tests showed a decrease in server response time while maintaining or reducing CPU utilization compared to the standard VMS QIO interface.