OpenVMS Undocumented Features : PARSEC Group

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

A comment that does something

When included as a comment, and surrounded by apostrophes, the F$VERIFY lexical function can still execute. Note in the example that the first F$VERIFY is commented out and still enables verification. The second F$VERIFY is also commented out but disables verification.

$! ver.com
$ set noverify
$! do nothing before
$! do nothing 'f$verify(1)'
$! do nothing middle
$! do nothing 'f$verify(0)'
$! do nothing after
$ set noverify

$ @ver
$! do nothing 0
$! do nothing middle

Debugging ACME Login

A logical name may be defined to cause the ACME server to log its activities. If LGI$TRACE is defined as 1, and the ACME server is restarted, then the SYS$MANAGER:ACME$SERVER.LOG file will be loaded with information about the steps taken.

$ define /system /executive_mode lgi$trace 1
$ set server acme /restart

Directory qualifiers

The DIRECTORY command allows displaying up to 9 different dates related to a file. All 9 of these are displayed with the /FULL qualifier, each of the others may be selected with /DATE=<date-format>. Four of these are documented as being available to select files for the /SINCE and /BEFORE qualifiers. Three additional qualifiers are available, but are not documented. These three are ACCESS, ATTRIBUTES and UPDATE_DATA. A short description for each of these dates is included in HELP DIRECTORY /DATE.

Date	/SINCE and /BEFORE
ACCESSED	Undocumented
ATTRIBUTES	Undocumented
BACKUP	Documented
CREATED	Documented
DATA_MODIFIED	Undocumented
EFFECTIVE	Unavailable
EXPIRED	Documented
MODIFIED	Documented
RECORDING	Unavailable

The two unavilable options, /EFFECTIVE and /RECORDING, are existing qualifiers to the DIRECTORY command but do not affect the results of the command.

Another qualifier, /LINKCOUNT, may be used to display the link count of a file. This information is available with /FULL, it just wasn't documented as a separate qualifier.

Thanks to Joe Sewell for providing information about the extra date qualifiers to this command.

Disabling and Enabling Queues

A queue may be disabled. The queue must be stopped before it can be disabled. Once disabled, it may not be started with the START /QUEUE command until it has been re-enabled. The SHOW QUEUE command displays the queue as disabled.

$ disable queue hpj4000
$ show queue hpj4000
Printer queue HPJ4000, disabled, on CLASS3::"10.100.0.241:3001", mounted form DEFAULT
$ start /queue hpj4000
%JBC-W-ENABLEQUE, queue must be enabled before it can be started
$ enable queue hpj4000
$ start /queue hpj4000
$ show queue hpj4000
Printer queue HPJ4000, idle, on CLASS3::"10.100.0.241:3001", mounted form DEFAULT

This undocumented feature, and others, has been supplied by Phillip Heblig with DBS.

EDIT /TPU Motif Widget Defaults

The EDIT /TPU command supports the /DEFAULTS=file-spec qualifier. This qualifier allows the user to specify the name of a file to be used with the DECwindows interface to provide the attributes for the widgets. The default file used is DECW$SYSTEM_DEFAULTS:TPU.DAT. This file includes the window and application title and window placement. The file below shows the default settings for these.

# DECTPU V3.2 2006-06-29 23:19 defaults
#
# @ Copyright 2006 2003 Hewlett-Packard Development Company, L.P.
#
#
# The following are all the resource names that DECTPU supports.
#
Tpu.Tpu$MainWindow.Title:               DECTPU © Copyright 2003 Hewlett-Packard Development Company, L.P.
Tpu.Tpu$MainWindow.ApplicationTitle:    DECTPU
Tpu.Tpu$MainWindow.IconName:            DECTPU
Tpu.Tpu$MainWindow.X:                   100
Tpu.Tpu$MainWindow.Y:                   100
#
# The following resource names are commented out so that users can specify
# *rows and *columns and have DECTPU obey those directives. If DECTPU finds
# finds no resource names governing the number of rows and columns it should
# have, it uses 24 rows and 80 columns.
#
#Tpu.Tpu$MainWindow.Columns:    80
#Tpu.Tpu$MainWindow.Rows:       24

MAIL /SERVER Command

The MAIL command is normally used to invoke the OpenVMS mail utility for sending and receiving e-mail. When invoked with the /SERVER qualifier, this command starts up the mail server for network communication.

Thanks to Phillip Heblig for bringing this feature to our attention.

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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.