DECsystem 5900 CPU System Manual

This "DECsystem 5900 CPU System Manual" is a comprehensive guide for Digital Service representatives, providing an in-depth view of the CPU's operations and troubleshooting.

The document covers:

• System Overview: Details the DECsystem 5900's hardware architecture, main components (CPU card, memory modules, TURBOchannel, SCSI drives), internal ASICs, and external connectors.
• Modes of Operation: Outlines console mode (for maintenance and diagnostics) and operating mode (for regular software operations), explaining how to manage system software (booting, shutdown) within these modes.

• Troubleshooting: Provides an overview of general troubleshooting techniques and detailed information on identifying failed Field-Replaceable Units (FRUs) using:

  • LED displays (diagnostic, CPU module, drawer).
  • Configuration displays (cnfg command) to check installed hardware and memory.
  • Various error messages (test, console exception, memory errors) and their interpretation.
  • Understanding system addresses for locating malfunctions.
  • Accessing ULTRIX error logs for post-failure analysis.

• Diagnostic Tools: Explains how to use console commands to run diagnostic tests (including power-up self-tests, individual module tests) and create/execute test scripts.

• Appendices: Offer extensive technical details, including a comprehensive reference for console commands and their error messages, detailed descriptions of base system self-test commands and their associated error codes, CPU and system register information, and connector pin assignments for various interfaces.
• ULTRIX System Exercisers: Describes software-based tools for exercising different system components (file system, memory, disk, tape, network, communications, line printer) under the ULTRIX operating system.

The manual is designed to equip service personnel with the knowledge and tools necessary to diagnose and resolve issues with the DECsystem 5900 CPU.