VMS Internals I

This document is a technical manual detailing the internal workings of the VMS operating system. It is divided into several sections, each focusing on a specific aspect of VMS.

The document includes:

• Educational Services: This introductory section likely outlines the purpose and target audience of the document.
• VMS Internals I: Mechanisms and Overview: This is the main title, indicating the document's focus on the fundamental mechanisms and overall architecture of VMS.
• Source Listings Book: This suggests that the document contains actual source code or detailed explanations of the source code for various VMS components.
• EY-9768E-DA-0002: This is the document order number.

The document's content appears to be highly technical, likely intended for system programmers, developers, or advanced users who need a deep understanding of VMS. It covers topics such as:

• AST (Asynchronous System Trap) Handling: Details are provided on AST enqueueing, delivery, and related mechanisms (e.g., ASTDEL.LIS, SCH$ASTDEL, KAST).
• Process Management: Information on process scheduling (SCHED.LIS), process creation (SYSCREPRC.LIS), and process suspension/resumption (EXE$SUSPEND, EXE$RESUME).
• System Services: Explanations of how system services are dispatched and handled, including exceptions and various modes of operation (e.g., SYSTEM_SERVICE_DISPATCHER.LIS, SYSTEM_SERVICE_EXIT.LIS).
• Swapping and Memory Management: Details on how the swapper manages process working sets and memory allocation (e.g., SWAPPER.LIS, SYSWAIT.LIS, FILLPHD).
• System Parameters (SYSGEN): A comprehensive listing of system parameters, their defaults, and their purpose (e.g., SYSPARAM.LIS, SYSWAIT.LIS).
• Command Language Interpreter (CLI) and Shell: Information on how the shell processes commands and manages system resources (e.g., SHELL.LIS).

The document is extensive, with numerous sections and subroutines, indicating a thorough treatment of VMS internals. It also includes a history of modifications for various modules, suggesting a versioned and evolving system.