OpenVMS Programming Concepts Manual

This document, the "OpenVMS Programming Concepts Manual" (Order Number AA-PV67B-TK), serves as a comprehensive guide for system and application programmers working within the OpenVMS operating environment. It focuses on programming features, providing detailed information on process management, communication, and synchronization.

Summary of Key Chapters:

• Process Management: Covers process creation (spawned and detached processes), execution contexts, and process control (such as obtaining process information and setting privileges).
• Process Communication: Details methods for communication within a process (local event flags, logical names, common areas) and between processes (mailboxes, global sections, and lock management services).
• Asynchronous Operations: Explains the use of Asynchronous System Traps (ASTs) for handling asynchronous events.
• System Time and Timers: Describes system time formats, date/time conversion routines, and how to manage timer requests and wakeups.
• Run-Time Library (RTL) and System Services: Provides guidance on using RTL routines to access operating system components, including command language interpretation and VAX machine instructions, as well as complex I/O operations (like screen management) and simple file I/O operations.
• Condition Handling and Synchronization: Details the OpenVMS Condition Handling Facility for managing exceptions, signaling, and message display. It also covers synchronization techniques, including event flags and the lock manager, for managing data access in multiprocessor environments.
• Memory Management: Discusses memory allocation routines at different levels (system services, RTL page management, and RTL heap management) and memory mapping (sections, global sections, and page frame sections), with specific information provided for both VAX and AXP (Alpha) architectures.
• Security: Explains the OpenVMS protection scheme, including identifiers, the rights database, Access Control Lists (ACLs), security auditing, and site-specific security policies.
• Image Initialization: Describes the mechanism for initializing images and declaring initialization routines.
• Distributed Systems: Provides information on using the Digital Distributed Name Service (DECdns) and the Distributed Transaction Manager (DECdtm) for managing distributed resources and transactions.