UNIX applications and tools on OpenVMS perform better on ODS-5 volumes due to the additional file naming characteristics such as
longer filenames, filenames with mixed case characters, filenames with multiple dots, and filenames with characters not legal in an
ODS-2 volume. These features are commonly used by UNIX style applications and tools.
There are some situations where use of an ODS-5 volume may not be desirable, for example, if compatibility with VAX or with older
OpenVMS/Alpha systems is needed. Please refer to the chapters on Managing Storage Media and Using Files and Directories in the
System Managers manual.
An ODS-2 disk can be easily converted to ODS-5. Close all applications using the disk, and dismount the disk. Remount it
privately. Then use the command:
$ SET VOLUME/STRUCTURE=5 disk
If you plan to use GNV for the UNIX tools and utilities it provides, you should install it on your system disk and your system disk
should be an ODS-5 volume. The system disk can be changed from ODS-2 to ODS-5, however, you will need to boot an alternate system
disk, or boot the OpenVMS installation CD to accomplish this. Once you have booted, use the
SET VOLUME command shown
above to convert your system disk from ODS-2 to ODS-5. Then reboot your system using the converted system disk.
In addition to setting a volume to ODS-5, you may also want to enable hardlinks. For example, you may want to
enable hardlinks to create a familiar UNIX development environment.
The command to enable hardlink support is:
$ SET VOLUME/VOLUME_CHARACTERISTICS=HARDLINKS disk
To use files with extended filenames, the following DCL command enables longer filenames for your session:
$ SET PROCESS/PARSE=EXTENDED
To use mixed or lowercase filenames the following DCL command enables it for your session:
$ SET PROCESS/CASE=SENSITIVE
Note: These last two commands need to be done for the process each time you login. If you are going to need these functions
all of the time, include them in your LOGIN.COM.