VAX/VMS Summary Description and Glossary

This document, the VAX/VMS Summary Description and Glossary (Order No. AA-00228-TE, March 1980, VAX/VMS V02), serves as an introduction to the basic concepts of the VAX/VMS operating system. It is designed for advanced users, such as system programmers and system managers, and is a revised version of a previous summary.

The document covers fundamental aspects of the VAX/VMS operating system, including:

• Introduction to VAX-11 Processor: Details hardware definitions of processes, 32-bit addresses, the four processor access modes (User, Supervisor, Executive, Kernel), and the native and compatibility mode instruction sets (including RSX-11M emulation).
• Processes: Explains processes as the basic schedulable entities, their virtual address space (process and system space), how their characteristics are defined (User Authorization File, OS, processor), process priorities, and scheduling mechanisms.
• Memory Management: Describes concepts like working sets, balance sets, the mapping of virtual to physical memory using page tables, and memory swapping.
• Process Control and Interprocess Communication: Outlines methods for intraprocess control (local event flags, asynchronous system traps, condition handlers, hibernation, timer services) and interprocess communication (UIC-based protection, subprocesses, mailboxes, global sections, and DECnet logical links).
• I/O System: Provides an overview of I/O operations, system services, VAX-11 Record Management Services (RMS), the Files-11 disk structure, file protection, logical names, process-permanent files, and network capabilities (DECnet).
• Languages, Libraries, Linking, and Sharing: Discusses supported programming languages (VAX-11 MACRO, FORTRAN, BASIC, COBOL-74, PASCAL, BLISS-32), the role of libraries and the VAX-11 Linker in producing executable and shareable images, and memory sharing via global sections.
• System Management and Operation: Covers practical aspects of system control, including spooling, batch processing, accounting, error logging, online diagnostic programs, system recovery, operator utilities, and maintenance updates.
• Compatibility Mode: Explains how VAX/VMS supports running PDP-11 and RSX-11M programs.

The document concludes with an Appendix detailing process states and system events, and a comprehensive Glossary of VAX-11 terms.