HP OpenVMS Delta,XDelta Debugger Manual

This manual describes the HP OpenVMS DELTA and XDELTA debuggers, tools designed for programmers to debug system code, device drivers, and other images running in privileged processor-access modes or at elevated interrupt priority levels (IPLs).

Key distinctions and features include:

• OpenVMS DELTA: Used for debugging programs that execute in privileged processor mode at Interrupt Priority Level 0, operating within a process context. It requires specific privileges (like CMKRNL or CMEXEC) for certain operations.
• OpenVMS XDELTA: Used for debugging system software running at elevated IPLs, operating in a system context rather than being process-specific. Invoking XDELTA typically requires booting the system with specific commands, and its existence is terminated upon rebooting without it. XDELTA generally does not require user privileges.

The manual provides comprehensive guidance on:

• Invocation and Termination: Steps for starting and exiting debugging sessions for both DELTA and XDELTA on OpenVMS I64, Alpha, and VAX systems.
• Breakpoints: How to set, clear, and manage simple and complex breakpoints, including accessing initial breakpoints and handling them in multiprocessor environments.
• Symbols and Expressions: Understanding the symbols provided by the debuggers for referencing registers and memory, forming numeric expressions, and managing floating-point register support.
• Debugging Programs: Detailed instructions on referencing addresses and registers (with platform-specific considerations for I64, Alpha, and VAX architectures), interpreting error messages, and debugging kernel-mode code or installed/shareable images. It also addresses scenarios like single-stepping failures and code mismatches.
• Command Reference: A summary and detailed descriptions of a wide array of commands used to control debugging sessions, including displaying and modifying memory contents (in various modes like byte, word, longword, quadword, ASCII, or instruction mode), loading base registers, executing command strings, dumping memory regions, and validating queues.
• Platform Specifics: The document outlines specific restrictions for XDELTA on OpenVMS I64 systems regarding certain hardware registers and provides distinct examples and procedures tailored for I64, Alpha, and VAX platforms where applicable.

Appendices offer sample debugging sessions for each supported OpenVMS platform to illustrate practical usage.