HP OpenVMS System Manager's Manual, Volume 1:...

Using Files and Directories

Considerations Before Enabling ODS-5 Volumes

Controlling Access to ODS-5 Volumes

Guidelines for Using Extended File Specifications on OpenVMS Applications  

• Review all ODS-5 considerations. (See Considerations for System Management.)



• Understand the support levels for different OpenVMS (See Levels of Support for Extended File Specifications.) applications.



• Segregate applications that do not support ODS-5 or have not been tested with ODS-5 names or volumes. (See Non-Supported OpenVMS Components (No Extended File Naming Support).)



• Review the guidelines for setting users' expectations in Setting Users' Expectations of Extended File Specifications.

HP recommends that you enable ODS-5 disks in a homogeneous OpenVMS Version 7.2 Alpha cluster only.

Levels of Support for Extended File Specifications  

To help determine the expected behavior of OpenVMS utilities and commands for ODS-5, the following levels of support have been established. Each level outlines the acceptable behavior of a utility or command when it encounters an extended (ODS-5 compliant) file specification.

The levels of support for ODS-5, from full support to no support, are defined in Sections Full Support through No Support for ODS-5.

Full Support  

OpenVMS utilities and commands that offer full support for ODS-5 have been specifically modified to take advantage of all the features of extended file naming. These utilities and commands should accept and handle extended file specifications without error while maintaining the case as created.¹

In addition, OpenVMS commands and utilities that fully support Extended File Specifications can accept and produce long file specifications that exceed the traditional 255-byte limit in their original form²--without requiring them to be abbreviated in Directory ID (DID) or File ID (FID) format.

The following DCL commands and OpenVMS utilities provide full support for extended file names:

• ANALYZE /AUDIT



• ANALYZE /DISK



• ANALYZE /RMS



• BACKUP



• CONVERT



• CONVERT /RECLAIM



• COPY



• CREATE /DIRECTORY



• DELETE



• DIRECTORY



• DUMP



• EDIT /ACL



• EXCHANGE /NETWORK



• FDL



• PURGE



• RECOVER/RMS



• RENAME



• SEARCH



• SET SECURITY



• SYSMAN



• TYPE

Default Support  

OpenVMS utilities and commands with default support have had little or no modification to take advantage of Extended File Specifications. These utilities and commands are expected to handle most of the attributes of extended file specifications (such as new characters and deep directory structures) correctly. However, file names may be created or displayed with the wrong case.

In contrast with utilities that have full support, utilities with default support rely on DID and FID abbreviation offered by RMS to handle long file specifications. As a result, these utilities are subject to the following restrictions related to DID and FID abbreviation:

• Matching operations in an environment where FID abbreviation is used may not always work as expected. For example, wildcard matching operations may not capture all target file names because the long file names may be represented in their numeric FID-abbreviated form. This restriction specifically applies to matching operations that are performed outside of RMS.



• Wildcards and sticky defaults cannot be used with a FID abbreviation. For example, the following commands are illegal:

  $ DIRECTORY a[1,2,3]*.txt
  $ COPY a[1,2,3].txt *.txt2

  Because a FID abbreviation is a unique numeric representation of one file, it cannot be used to represent or match any other file.



• Creating a file using a FID abbreviation is illegal.

For more information about DID abbreviations and FID abbreviations, see the OpenVMS User's Manual .

No Support for Extended File Naming  

OpenVMS utilities and commands that do not support extended file names can function on ODS-5 volumes; however, they are restricted to operating with traditional file specifications only. These utilities and commands should be used carefully on ODS-5 volumes because HP cannot ensure that they will function successfully when they encounter extended file specifications.

Non-Supported OpenVMS Components (No ODS-5 Support) and Non-Supported OpenVMS Components (No Extended File Naming Support) list the OpenVMS utilities and commands that do not support Extended File Specifications because of limitations with either handling extended file names or the ODS-5 volume structure.

No Support for ODS-5  

OpenVMS utilities and commands that do not support the ODS-5 volume structure cannot handle extended file names. These utilities and commands should be used carefully on ODS-5 volumes because HP cannot ensure that they will function successfully even when they only encounter traditional file specifications.

Non-Supported OpenVMS Components (No ODS-5 Support) and Non-Supported OpenVMS Components (No Extended File Naming Support) list the OpenVMS utilities and commands that do not support Extended File Specifications because of limitations with either the ODS-5 volume structure or with handling extended file names.

Table 3   Non-Supported OpenVMS Components (No ODS-5 Support)

Component	Notes
Disk defragmenters	Unsupported unless a specific defragmentation tool documents that it has been updated to support an ODS-5 volume. 3

Table 4   Non-Supported OpenVMS Components (No Extended File Naming Support)

Component	Notes
Code compilers	Cannot use extended file names for object files. However, code compilers can create applications that support extended names.
INSTALL Known images	Do not install an image with an extended file name as a known image.
LINK	Cannot output an image with an extended file name.
MONITOR	Cannot reliably process extended file names.
Network files (NET*.DAT)	Do not rename to an extended file name.
Object modules (.OBJ)	Do not rename to an extended file name.
Page and swap files	Do not use an extended file name.
SYSGEN	Do not write a parameter file with an extended file name.
System startup files	Do not rename to an extended file name.

1	When creating the first version of a new file, the case of the new file matches that case specified by the user. When creating subsequent versions of an existing file, the case remains the same as the original version.

2	If you are typing a long file specification on a DCL command line, DCL still limits the command line length to 255 bytes.

3	Note that DFO has been modified to support ODS-5 volumes.

( Number takes you back )

Considerations Before Enabling ODS-5 Volumes

Controlling Access to ODS-5 Volumes