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OpenVMS Undocumented Features

This is the most complete collection of undocumented features we can find for OpenVMS. Some of these have been around since the time when it was called VMS while others are more current and have been added to OpenVMS V8.n. These features:

  • Are NOT documented (if they were, they wouldn't belong here)
  • Are NOT supported by PARSEC Group or HP
  • Are NOT guaranteed to work
  • May NOT exist in all versions of OpenVMS; past, present and future
  • Are subject to change, removal, enhancement or being documented at the whim of OpenVMS engineering
  • May be fun to know the next time you play OpenVMS trivial pursuit
  • May help you get your job done easier and faster
  • May help you impress your boss with your knowledge of the obscure

LGI logical names

Define LGI$PASSWORD_NOCHANGE_DAYS as a system-wide, executive-mode logical name to set a minimum number of days that must pass between password changes. This prevents someone from changing their password multiple times in one day to reuse the current password by changing enough to get around the password history. Of course, if I catch someone doing this, I am likely to set the GENPWD flag for that user to force them to use system generated passwords.

$ set process/privilege=(sysnam,cmexec)
$ define /system /executive_mode lgi$password_nochange_days 3
$ set password
Old password:
New password:
$ set password
Old password:
New password:
%SET-F-PWDLOCKED, password is locked to prevent change


Define LGI$EXPIRATION_WARNING_DAYS as a system-wide, executive-mode logical name to set the number of days warning provided when a password will expire. By setting this to a value of 11, users can be ensured of receiving a warning before it expires even if they take a one week vacation. By setting it extremely large, as in the example below, users can be notified often enough to completely ignore the warning.

$ define /system /executive_mode lgi$expiration_warning_days 900
$ set host 0

 Welcome to OpenVMS (TM) Alpha Operating System, Version V8.3

Username: williams
   Welcome to OpenVMS (TM) Alpha Operating System, Version V8.3 on node CLASS2
    Last interactive login on Thursday,  8-MAR-2007 10:47:55.12
    Last non-interactive login on Tuesday,  6-MAR-2007 01:22:09.96
WARNING - Your password expires on Monday, 24-AUG-2009 11:06:48.18

Note: These have been added to the OpenVMS V8.4 documentation.


Executing the command SET AUDIT /SERVER=LOCK locks the security auditing settings, thus preventing any changes. This is effective until the system is rebooted.

Setting OpenVMS Version on Alpha

You may run the OpenVMS Alpha version of your choice. Not available for OpenVMS VAX or OpenVMS I64.

$ set def sys$common:[sys$ldr]
$ run sysver
00010938: V8.3
SYSVERSION> replace v8.52
00010938: V8.52

Now reboot and SHOW SYSTEM to see the fastest (unsupported) method of getting to another version of OpenVMS.

$ show system/noprocess
OpenVMS V8.52 on node CLASS2   8-FEB-2007 08:39:23.23  Uptime  0 00:02:15

Setting OpenVMS Version on VAX

You may run the OpenVMS VAX version of your choice. Do not use this method on OpenVMS Alpha or OpenVMS I64.

$ set default sys$common:[sys$ldr]
$ copy sys.exe sys.exe_v73
$ patch sys.exe
PATCH Version 7.1 26-JUL-1995
%PATCH-I-NOLCL, image does not contain local symbols
%PATCH-I-NOGBL, some or all global symbols not accessible
PATCH>define sys$gq_version=800044b8
symbol "SYS$GQ_VERSION" defined as 800044B8
PATCH>set mode ascii
PATCH>examine sys$gq_version:sys$gq_version+7
800044BC: '    '
PATCH>replace sys$gq_version
OLD>'    '
NEW>'-44 '
old: SYS$GQ_VERSION: 'V7.3'
old: 800044BC: '    '
new: SYS$GQ_VERSION: 'V8.5'
new: 800044BC: '-44 '
PATCH>examine sys$gq_version:sys$gq_version+7
800044BC: '-44 '
%PATCH-I-WRTFIL, updating image file SYS$COMMON:[SYS$LDR]SYS.EXE;7

Now reboot and SHOW SYSTEM to see the fastest (unsupported) method of getting to another version of OpenVMS.

$ show system/noprocess
OpenVMS V8.5-44 on node CLASS9 7-MAR-2007 12:48:08.97 Uptime 0 00:04:33

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Please enjoy these features at your own risk. If you are aware of other features in OpenVMS which are currently undocumented, you may use our inquiry form to inform us. We may then add it to our list.