Introduction to VAX-11 Record Management Services

This document, "Introduction to VAX-11 Record Management Services," published in March 1980 (Order No. AA-D024C-TE), serves as an introductory guide to the file and record access subsystem of the VAX/VMS operating system (V02). Its primary purpose is to explain fundamental file concepts and their application within VAX-11 Record Management Services (RMS), rather than detailing programming techniques.

The manual covers:

1. Basic File Storage Concepts: It introduces how VAX-11 RMS interacts with magnetic storage media, describing disk concepts like Files-11 structure (blocks, clusters, extents, tracks, cylinders, index files, directories) and magnetic tape concepts (sequential organization, interrecord gaps, record blocking, and multi-volume files).
2. VAX-11 RMS File Structures: It elaborates on the three primary file organizations supported on disk:
   • Sequential: Records stored in physical order, accessed one after another.
   • Relative: Records stored in fixed-length cells, allowing direct access by relative record number.
   • Indexed: The most flexible, allowing records to be stored and retrieved based on primary and optional alternate keys, enabling sorted sequential access or random access by key value. It also describes various record access modes (Sequential, Random by Key, Random by Record's File Address (RFA)) and the ability to switch between them using "dynamic access." Different record formats (fixed-length, variable-length, and variable with fixed-length control) are also detailed.
3. File and Record Processing: The document outlines operations at two levels:
   • File Level: Operations for managing the file as a whole, including creating, opening, displaying attributes, extending, modifying, closing, and erasing files. It also explains file protection mechanisms and file sharing capabilities, allowing multiple programs to concurrently access a file (primarily on disk).
   • Record Level: Operations for manipulating individual records, such as reading (Get), writing (Put), locating (Find), updating, and deleting. It differentiates between synchronous and asynchronous I/O and move and locate record transfer modes. It also details record locking for managing concurrent access to records in relative and indexed files.
4. Block Input/Output: A brief mention of a low-level method allowing direct access to file blocks, bypassing RMS record processing.

In essence, the document provides a foundational overview of VAX-11 RMS's capabilities for efficient data management, explaining the logical and physical organization of files and records, and the various methods for accessing and manipulating them within the VAX/VMS operating environment.