Guide to OpenVMS File Applications

This document serves as a comprehensive guide for application programmers and designers on utilizing OpenVMS Record Management Services (RMS) for efficient data management across disks and magnetic tapes. It introduces fundamental data management concepts such as files, records, fields, and bytes, and details various disk (Files-11 On-Disk Structure) and magnetic tape concepts, including their physical and logical structures, control files, and labeling standards.

The guide thoroughly explains the three main file organizations—sequential, relative, and indexed—along with their supported record access modes (sequential, random by key, relative record number, and Record File Address, or RFA). A significant emphasis is placed on "tuning" files for optimal performance, covering design considerations like speed, space efficiency, and shared access. It delves into file design attributes such as initial allocation, contiguity, extend quantity, I/O units (blocks, multiblocks, buckets), multiple areas, and bucket fill factors, as well as processing options like multiple buffers, deferred-write, global buffers, and read-ahead/write-behind. Performance in VMScluster environments, including record locking and I/O considerations, is also discussed.

Furthermore, the document outlines the process of creating and populating files, detailing the use of RMS control blocks, the File Definition Language (FDL) and its utilities (Edit/FDL, Create/FDL, Convert), and FDL routines. It explains file protection mechanisms (UIC-based and ACLs), file specification formats, logical names, and RMS parsing rules for locating files on both local and remote nodes. Lastly, it covers essential file maintenance procedures, such as viewing file characteristics, performing error checks, generating statistics reports, optimizing and redesigning files, making files contiguous, reclaiming unused space in indexed files, reorganizing files, and creating archive copies. The document concludes with an appendix on Edit/FDL utility optimization algorithms and a glossary of terms.