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From: [email protected] (Hoff Hoffman)
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Organization: HP
Subject: OpenVMS Frequently Asked Questions (FAQ), Part 5/11
Summary: This posting contains answers to frequently asked questions about
the HP OpenVMS operating system, and the computer systems on which
it runs.
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Date: Sun, 04 Sep 2005 19:59:10 GMT
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Archive-name: dec-faq/vms/part5
Posting-Frequency: quarterly
Last-modified: 02 Sep 2005
Version: VMSFAQ_20050902-05.TXT

System Management Information

________________________________________________________________
Table 5-1 (Cont.) PCSI Generation Number

_______________________________________________________
Generation
Number____________Generation_Source____________________

0050160000 V7.2-2

005017xxxx V7.2-2 ECOs

0060000000 V7.3

006001xxxx V7.3 ECOs

0060020000 V7.3-1

006003xxxx V7.3-1 ECOs

0060100000 V7.3-2

006011xxxx V7.3-2 ECOs

0070040000 V8.2

007005xxxx V8.2 ECOs

0070060000 V8.2-1

_________007007xxxx________V8.2-1_ECOs__________________________

__________________________________________________________
5.29 How can I tell what software (and version) is installed?

There is unfortunately no consistent nor single way to
make this determination-this is one of the reasons that
a move to PCSI installations is underway.

On OpenVMS Alpha, you can use VMSINSTAL.HISTORY and
PRODUCT SHOW PRODUCT to determine what packages have
been installed via the VMSINSTAL and PCSI tools,
respectively.

To see which OpenVMS Alpha ECO kits have been applied,
look in VMSINSTAL.HISTORY on OpenVMS Alpha prior to
V7.1-2, and use PRODUCT SHOW PRODUCT/FULL on OpenVMS
Alpha V7.1-2 and later.

On OpenVMS VAX, you can use PRODUCT SHOW PRODUCT and
(for software that is installed via VMSINSTAL on V7.3
and later) in VMSINSTAL.HISTORY.

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For products installed on OpenVMS VAX prior to V7.3
using VMSINSTAL, there is no reliable way to determine
what products have been installed. If the product
provides a RELEASE_NOTES file (as many do), you
can look for the list of these files via DIRECTORY
SYS$HELP:*.RELEASE_NOTES. Again, this approach is NOT
reliable: some kits do not provide release notes, some
system managers will install only the release notes,
some system managers will delete release notes, and
release notes for multiple versions can be present.

On most packages, you can generally use ANALYZE/IMAGE
on one of the core images, looking at the image
identification area. Some of the product-specific
mechanisms available are:

o DQS DQS$VERSION logical name

o C CC/VERSION

o C++ CXX/VERSION

o TCP/IP TCPIP SHOW VERSION command

__________________________________________________________
5.30 What file checksum tools are available for OpenVMS?

The undocumented (prior to V8.2) DCL command CHECKSUM
is the usual means, and provides a rather simple-minded
checksum suitable to detect basic file corruptions.
Starting with V8.2, additional algorithms beyond the
classic XOR scheme are available.

One of the most common schemes beyond the CHECKSUM
XOR scheme is MD5, and information and a source code
example are available via the MD5 RFC. As of this
writing, pre-built versions of MD5 are expected to be
made available at or via the OpenVMS Freeware website
( http://www.hp.com/go/openvms/freeware/ ), and MD5 is
expected to be made available on an OpenVMS Freeware
release after V7.0. Also see the CHECKSUM/ALGORITHM=MD5
command on OpenVMS V8.2 and later.

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System Management Information

The OpenVMS Alpha ECO (patch) kit checksums available
at the ECO website are determined using the following
DCL command sequence:

$ CHECKSUM kitname.pcsi-dcx_axpexe
$ SHOW SYMBOL CHECKSUM$CHECKSUM

See Section 5.17 for information on acquiring OpenVMS
ECO (patch) kits.

__________________________________________________________
5.31 What (and where) is the OpenVMS Management Station?

For information and current kits for the OpenVMS
Management Station (OMS), a PC-based tool that permits
you to manage an OpenVMS system, please see:

o http://www.openvms.compaq.com/openvms/products/argus/

__________________________________________________________
5.32 How to determine current disk fragmentation level?

The HP OpenVMS Disk File Optimizer (DFO)
defragmentation package provides a fragmentation
monitoring tool, and a DFO product authorization key
(PAK) is not required for the fragmentation reporting
tool:

$ DEFRAG SHOW/VOLUME ddcu:

The DFU tool available on the OpenVMS Freeware can
generate a report on the disk fragmentation:

DFU> REPORT ddcu:

__________________________________________________________
5.33 SYSBOOT-I-FILENOTLOC, Unable to locate SYS$CPU_ROUTINES?

A message at the OpenVMS Alpha bootstrap such as the
following:

%SYSBOOT-I-FILENOTLOC, Unable to locate
SYS$CPU_ROUTINES_1C02.EXE
%SYSBOOT-E-LDFAIL, failed to load execlet,
status = 00000910

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System Management Information

indicates that the particular OpenVMS Alpha release
does not contain support for the target platform. In
this case, OpenVMS does not recognize Alpha family 1C
member 02 as a supported platform. A later version of
OpenVMS might support the platform, or there might be
no support on any release. Ensure that you have the
most current firmware, and review the minimum version
requirements for the platform.

The execlet load failure and other similar bootstrap
status values can often be decoded using either of the
following techniques:

$ exit %x910
%SYSTEM-W-NOSUCHFILE, no such file
$

$ x = f$message(%x910)
$ show symbol x
X = "%SYSTEM-W-NOSUCHFILE, no such file"
$

Also see Section 14.4.4.1.

__________________________________________________________
5.34 How can I customize the DCPS device control for a new
printer?

To customize DCPS for an otherwise unsupported printer,
you can try the following sequence:

o Extract the most closely-associated setup modules
from the existing device control library,
DCPS$DEVCTL.TLB. (For instance, you can probably
extract and use the HP LaserJet 4000 series
definitions for the HP LaserJet 4050 series. Each
printer will vary, please consult the printer
documentation for specifics and requirements.)

o rename each extracted setup module to a
corresponding:

LPS$$UNRECOGNIZED_*

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System Management Information

o Insert all of the above-renamed setup modules into a
newly-created device control library specific to the
new printer:

$ LIBRARY/TEXT/CREATE -
SYS$COMMON:[SYSLIB]HP4050_DEVCTL.TLB
LPS$$UNRECOGNIZED*

The above assumes the filename HP4050_DEVCTL.TLB,
alter as required.

o Set up your DCPS startup procedures to include a
search-list logical name such as:

$ DEFINE/SYSTEM/EXECUTIVE DCPS_HP4050_LIB -
SYS$LIBRARY:HP4050_DEVCTL.TLB, -
SYS$LIBRARY:DCPS$DEVCTL.TLB

o Supply DCPS_HP4050_LIB as the library parameter
in the queue startup for this printer, this
is the P3 parameter to the command procedure
SYS$STARTUP:DCPS$EXECUTION_QUEUE.COM.

o The HP4050_DEVCTL library may/will need to be
recreated and modules re-edited and replaced with
each DCPS upgrade, particularly if any modules
are updated in the original library. You will also
want to determine if the upgraded version of DCPS
directly supports the particular printer.

o To customize the processing of file extensions
within DCPS (to enable or disable graybar output,
for instance), use the information available in:

SYS$LIBRARY:DCPS$FILE_EXTENSION_DATA_TYPE.DAT_DEFAULT

to create your own site-specific:

SYS$LIBRARY:DCPS$FILE_EXTENSION_DATA_TYPE.DAT

Also see Section 5.15.

__________________________________________________________
5.35 Why do $GETDEV MOUNTCNT and SHOW DEVICE mount counts
differ?

MOUNTCNT returns the local mount count, while SHOW
DEVICE returns the cluster-wide mount count.

5-48

System Management Information

__________________________________________________________
5.36 What software is needed for Postscript printers?

The NorthLake PrintKit (www.nls.com) and DECprint
Supervisor (DCPS) are common choices for support of
Postscript printers on OpenVMS.

o http://www.nls.com/

o http://www.openvms.compaq.com/openvms/Print/print_
sw_prods.html

You may also require the installation of an IP
transport stack.

Also please see Section 15.2.2 and Section 15.2.3.

__________________________________________________________
5.37 How do I remove a PCSI-installed patch (ECO) kit?

You cannot PRODUCT REMOVE a PCSI patch (ECO) kit.

In order to remove an ECO kit, PCSI would have to have
copies of all the other version of the files from
all other patches and products that previously were
installed. This can clearly involve a large number of
files and a large archive of old file versions and a
substantial quantity of disk space. While removal is
clearly theoretically possible, it is not currently
implemented.

The following is the supported mechanism to remove a
PCSI patch kit.

1 Execute a PRODUCT SHOW PRODUCT product-name. /FULL
command. The "maintenance" column (132 column width)
shows the patches that have been installed. Keep a
copy of this listing.

2 Acquire kits for all of the maintenance kits listed.

3 Re-install the prior FULL version of the product.
This will remove all patch kits, setting to product
back to "original" condition.

4 Re-install all the patches in the list from step 1,
except those patches which you have determined you
do not want.

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System Management Information

The above information also applies to PCSI PARTIAL
kits.

__________________________________________________________
5.38 SYSINIT-E, error mounting system device, status=0072832C

This message can arise during an OpenVMS system
bootstrap...

%MOUNT-F-DIFVOLMNT, different volume already mounted on this device

For details and further information, use the DCL
command:

$ HELP/MESSAGE /STATUS=%X72832C

__________________________________________________________
5.39 Resolving License PAK Problems?

The PAK release date, the PAK termination date, and
the PAK version are the usual culprits when a license
product authorization key (PAK) check failure occurs.

The PAK termination date is the date when the license
PAK will expire.

The PAK release date is the date of the most recent
release date of the software package that will be
permitted by the particular license PAK. (The release
date check is analogous to a product version check.)
The PAK version indicates the most recent product
version that is permitted by the license.

Having multiple license PAKs registered (and active)
can also cause problems if an expired PAK gets loaded.
You will want to DISABLE license PAKs you do not wish
to have loaded.

Other problems include a failure to register each PAK
in all license databases throughout a multiple-system-
disk cluster, with a consistent set of /INCLUDE lists
specified across each of the duplicated PAKs.

Additionally, you could have an invalid LMF$LICENSE
logical name defined. (If no LMF$LICENSE logical
name is defined, the standard license database named
SYS$SYSTEM:LMF$LICENSE.LDB will be used.)

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System Management Information

You can display license failures by defining the
following logical name:

$ DEFINE/SYS/EXEC LMF$DISPLAY_OPCOM_MESSAGE TRUE

Enable your terminal as a license operator
(REPLY/ENABLE=LICENSE), define the LMF$DISPLAY_
OPCOM_MESSAGE logical name, and then try the failing
operation again. You should see one or more OPCOM
messages displayed.

If you have the LMF$DISPLAY_OPCOM_MESSAGE logical name
defined, you can (will?) see spurious license check
failures-various products will check for multiple
licenses, and a few products will check for PAKs that
either have not yet been or will not be issued. Once
you figure out which license has failed, you will want
to deassign this logical name.

Note

That there are no license check failures does not
indicate that the particular product or operation
or use is permissible per applicable licensing
agreements. Please consult the applicable
agreement(s) for licensing-related information
and requirements.

To register a license PAK on a DECwindows system
when DECwindows cannot start (because of an expired
license or other licensing problem), follow the steps
outlined in section Section 5.6 up through the use
of the AUTHORIZE command. In place of the AUTHORIZE
command, use the console to register the license PAKs.
Also see Section 12.4 for licensing and troubleshooting
information.

For information on licensing and on the numbers of
license units required for various products and various
platforms, the License Unit Requirements Table (LURT)
is available at:

o http://www.compaq.com/products/software/info/

5-51

System Management Information

__________________________________________________________
5.40 Changing the OpenVMS Version Number?

Fool your friends, baffle your enemies, run the OpenVMS
version of your choice!

On OpenVMS Alpha systems:

$ SET DEFAULT SYS$COMMON:[SYS$LDR]
$ RUN SYSVER
REPLACE V9.9
WRITE
$ EXIT

On OpenVMS VAX systems:

$ set default SYS$COMMON:[SYS$LDR]
$ copy SYS.EXE SYS.EXE_IN-CASE-I-FAIL
$ patch SYS.EXE
define sys$gq_version=800044b8
set mode ascii
!examine sys$gq_version
!examine sys$gq_version+4
deposit sys$gq_version = "V9.9"
deposit sys$gq_version+4 = " "
update
exit
$ Exit

Then reboot the system at your leisure.

__________________________________________________________
5.41 How to prevent users from choosing obvious passwords?

To prevent users from selecting obvious passwords on
OpenVMS, you will want to use the reserved password
(password screening) mechanism. Effectively, you merge
your list of reserved passwords into the existing
reserved words database maintained by OpenVMS. (You can
also then require all users to reset their passwords-
via the pre-expired password mechanism-thus forcing
users to select new passwords.) For details on the
password screening mechanism, of the reserved password
database (VMS$PASSWORD_DICTIONARY.DATA), and details
of how to merge your list of prohibited passwords
into the database, please see the associated chapter
in the OpenVMS security manual. For details of the

5-52

System Management Information

password expiration mechanism, see the AUTHORIZE
command qualifier /PWDEXPIRED.

You can also implement a site-specific password filter
with the information provided in the back of the
OpenVMS Programming Concepts manual. The password
filter permits you to establish particular and site-
specific password requirements. For details, please
see the system parameter LOAD_PWD_POLICY and the
programming concepts manual, and see the examples in
SYS$EXAMPLES:. (Examples and documentation on V7.3
and later reflect both platforms, the examples are
found only on OpenVMS VAX kits on earlier releases.
The capabilities have existed on both the VAX and Alpha
platforms for some time now.)

To verify current passwords, you can also use a
technique known to system crackers as the "dictionary
attack" - the mechanism that makes this attack somewhat
more difficult on OpenVMS is the hashing scheme used on
OpenVMS, and the file protections used for the SYSUAF
authorization database. Given a dictionary of words and
the unprotected contents of the SYSUAF file, a search
for obvious passwords can be performed. Interestingly,
a "dictionary attack" also has the unfortunate side-
effect of exposing the password to the user-while this
is clearly the goal of a system cracker, authorized
privileged and non-privileged system users should not
know nor have access to the (cleartext) passwords of
other users.

Accordingly, OpenVMS does not store the cleartest
password. Further, OpenVMS uses a password hashing
algorithm, not an encryption algorithm. This means that
storage of a cleartext password is deliberated avoided,
and the cleartext value is deliberately very difficult
to obtain. The hash is based on a Purdy Polynomial,
and the hash itself includes user-specific values in
addition to the password, values that make the results
of the password hash unique to each user.

Regardless of the use of a password hashing scheme, if
a copy of your password file should become available to
a system cracker, you will want to force all users to
use new passwords immediately.

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System Management Information

If you should require a user to verify a password,
use the username, the user's salt value (this value
is acquired via $getuai) and the user's specified
cleartext password, and compare the resulting hashed
value (using a call to $hash_password) against the
saved hashed password value (this value also acquired
via $getqui). For reasons of security, avoid saving
a cleartext password value in any data files, and do
not maintain the cleartext password in memory longer
than required. (Use of sys$acm on V7.3-1 and later is
recommended.)

Kerberos authentication (client and server) is
available on OpenVMS V7.3 and later. Integration of
Kerberos support into various Compaq and into third-
party products is expected.

External authentication is available in V7.3-1
and later, with support for user-written external
authentication in V7.3-2 and later.

If you are simply looking for OpenVMS access and
the SYSTEM and all other privileged passwords are
forgotten or otherwise unavailable, please see section
Section 5.6 and/or the OpenVMS documentation set.

Also please see the NCSC C2 guidelines in the OpenVMS
security manual.

__________________________________________________________
5.42__Please_help_me_with_the OpenVMS BACKUP utility?

5.42.1 Why isn't BACKUP/SINCE=BACKUP working?

If you are seeing more files backed up than previously,
you are seeing the result of a change that was made to
ensure BACKUP can perform an incrementation restoration
of the files. In particular, if a directory file
modification date changes, all files underneath it are
included in the BACKUP, in order to permit incremental
restoration should a directory file get renamed.

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System Management Information

_____________________________
5.42.1.1 Why has OpenVMS gone through the agony of this change?

When a directory is renamed, the modified date is
changed. When the restoration needs to restore the
directory and its contents, and the restoration should
not result in the restoration of the older directory
name when a series of incremental BACKUPs are restored.
Thus an incremental BACKUP operation needs to pick up
all of the changes.

Consider performing an incremental restoration, to
test the procedures. This testing was how OpenVMS
Engineering found out about the problem that was
latent with the old BACKUP selection scheme-the
old incremental BACKUP scheme would have missed
restoring any files under a renamed directory. Hence
the change to the selection mechanisms mentioned in
Section 5.42.1.

_____________________________
5.42.1.2 Can you get the old BACKUP behaviour back?

Yes, please see the /NOINCREMENTAL qualifier available
on recent OpenVMS versions (and ECO kits). Use of
this qualifier informs BACKUP that you are aware of
the limitations of the old BACKUP behaviour around
incremental disk restorations.

_____________________________
5.42.2 What can I do to improve BACKUP performance?

Use the documented commands in the manual for
performing incremental BACKUPs. Use the documented
incremental procedures. Don't try to use incremental
commands in a non-incremental context.

Also consider understanding and then using /NOALIAS,
which will likely be a bigger win than will anything to
do with the incremental BACKUPs, particularly on system
disks and any other disks with directory aliases.

See the OpenVMS documentation for additional details.

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System Management Information

Ignoring hardware performance and process quotas, the
performance of BACKUP during a disk saveset creation is
typically limited by three factors:

1 Default extend size

The default behavior can have poor performance,
as the extend operation can involve extensive
additional processing and I/O operations. Consider
changing the default extend value on the volume, or
change the extend for the process:

$ set rms/extend=65000

2 Output IO size

The default IO size for writing an RMS sequential
file is 32 blocks, an increase from the value of
16 blocks used on earlier versions. Setting this to
the maximum of 127 can reduce the number of IOs by
almost a factor of 4:

$ set rms/block=127

Note that the performance might be better on some
controllers if the block count is a multiple of 4 -
e.g. 124

3 Synchronous writes to the saveset

Starting with OpenVMS V7.3, you can now persuade
RMS to turn on write-behind for sequential files
opened unshared. (Please see the V7.3 release notes
or more recent documentation for details.) Enabling
the write-behind operations involves setting the
dynamic system parameter RMS_SEQFILE_WBH to 1.
This parameter is dynamic, and it can be enabled
and disabled without a reboot, and changes in its
setting can and will directly effect the running
system. In order to get the full benefit from write-
behind operations, you also need to increase the
RMS local buffer count from the default of 2 to a
larger number. Raising the value to 10 is probably a
reasonable first estimate for this value.

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System Management Information

$ run sys$system:sysman
PARAMETERS USE ACTIVE
PARAMETERS SET RMS_SEQFILE_WBH 1
PARAMETERS WRITE ACTIVE
EXIT
$ SET RMS/BUFFER=10/EXTEND=65000/BLOCK=127
$ BACKUP source-specification ddcu:[dir]saveset.bck/SAVE

_____________________________
5.42.3 Why is BACKUP not working as expected?

First, please take the time to review the BACKUP
documentation, and particularly the BACKUP command
examples. Then please download and install the most
current BACKUP eco kit. Finally, please please set the
process quotas per the System Management documentation.
These steps tend to resolve most problems seen.

BACKUP has a very complex interface, and there
are numerous command examples and extensive user
documentation available. For a simpler user interface
for BACKUP, please see the documentation for the
BACKUP$MANAGER tool.

As for recent BACKUP changes, oddities, bugs, etc:

o A change made in OpenVMS V6.2 WILL cause more files
to be included into a file-based BACKUP saveset
using /SINCE=BACKUP as all files underneath any
directory with a sufficiently recent (selected)
date will be included in the saveset. This change
was deliberate and intentional, and was mandated
by the need to provide a functional incremental
restoration.

Without the inclusion of these apparently-extra
files, an incremental saveset can NOT be reliably
restored.

o As part of the OpenVMS V6.2 change, the /SINCE
command-without the specification of the =BACKUP
keyword-selected more files than it should have.
This is a bug. This bug has been remedied in the
OpenVMS BACKUP source code and in some of (all of?)
the BACKUP ECO kits.

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System Management Information

When working with BACKUP, you will want to:

o Ensure you have your process quotas set per the
recommendations in the OpenVMS System Management
documentation. Deviation from these values can and
will lead to access violation (ACCVIO) and other
untoward behaviour.

o Get the current BACKUP ECO kit and install it BEFORE
you attempt to troubleshoot any problems.

o Learn about the /NOINCREMENTAL (new) and /NOALIAS
(V6.2 and later) command qualifiers. The former
qualifier returns to the pre-V6.2 behaviour of the
/SINCE file selection mechanism, while the latter
(specified with /IMAGE) reduces the replication
of files on system disks and other disks with file
alias and directory alias entries. Both of these can
reduce the numbers of files that will be selected
and thus included into the saveset.

Learn what /IGNORE=INTERLOCK means. This command
probably does not provide what you think it does-
those file system interlocks that this command is
ignoring were implemented for a reason, after all.
Ignoring these interlocks can lead to missed data
and potentially to corruptions to individual files
stored within the output saveset, corruptions that
may or may not be reported. For details on this
BACKUP command qualifier, please see the Ask The
Wizard topic (2467).

When working with the BACKUP callable API:

o Build your applications with the most current BACKUP
API available. Changes made to the V7.1-2 and V7.2
API were incompatible with the V7.1 and V7.2-1 and
later APIs, and this incompatibility was repaired
via a BACKUP ECO kit. Do NOT build your application
with the versions of the BACKUP API that shipped
with V7.1-2 and V7.2, as these are incompatible with
the BACKUP API constants that were used on other
versions.

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_____________________________
5.42.4 How do I fix a corrupt BACKUP saveset?

BACKUP savesets can be corrupted by FTP file transfers
and by tools such as zip (particularly when the zip
tool has not been asked to save and restore OpenVMS
file attributes or when it does not support OpenVMS
file attributes), as well as via other means of
corruptions.

If you have problems with the BACKUP savesets after
unzipping them or after an FTP file transfer, you can
try restoring the appropriate saveset attributes using
the tool:

$ @RESET_BACKUP_SAVESET_FILE_ATTRIBUTES.COM

This tool is available on the OpenVMS Freeware (in
the [000TOOLS] directory). The Freeware is available
at various sites-see the Freeware location listings
elsewhere in the FAQ-and other similar tools are also
available from various sources.

In various cases, a SET FILE/ATTRIBUTES command can
also be used. As the parameters of this command must be
varied as the target BACKUP saveset attributes vary,
this approach is not recommended.

Also see the "SITE VMS", /FDL, and various other file-
attributes options available in various FTP tools. (Not
all available FTP tools support any or all of these
options.)

Browser downloads (via FTP) and incorrect (binary or
ascii FTP transfer modes) are notorious for causing
RMS file corruptions and particularly BACKUP saveset
corruptions. You can sometimes help encourage the
browser to select the correct FTP transfer type code
(via RFC1738):

o ftp://host/urlname.ext;type=i ! request ftp
image/binary transfer

o ftp://host/urlname.ext;type=a ! request ftp
ascii/text transfer

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System Management Information

You can also often configure the particular web browser
to choose the appropriate transfer mode by default,
based on the particular file extensions, using a
customization menu available in most web browsers. You
can select that the specific file extentions involved
use the FTP binary transfer mode, which will reduce the
number of corruptions seen.

_____________________________
5.42.5 How do I write a BACKUP saveset to a remote tape?

How to do this correctly was described at DECUS long
ago. On the OpenVMS host with the tape drive, create
the following SAVE-SET.FDL file:

RECORD
FORMAT fixed
SIZE 8192

Then create BACKUP_SERVER.COM:

$ !
$ ! BACKUP_SERVER.COM - provide remote tape service for BACKUP.
$ !
$ set noon
$ set rms/network=16
$ allocate mka500 tapedev
$ mount/nounload/over:id/block=8192/assist tapedev
$ convert/fdl=SAVE-SET sys$net tapedev:save-set.
$ dismount/unload tapedev
$ stop/id=0

On the node where you want to do the backup, use the
DCL command:

$ backup -
srcfilespec -
node"user pwd"::"task=backup_server"/block=8192/save

One area which does not function here is the volume
switch; multi-reel or multi-cartridge savesets. Since
the tape is being written through DECnet and RMS and
the magtape ACP, BACKUP won't see the media switch
and will split an XOR group across the reel boundary.
BACKUP might well be willing to read such a multi-
reel or multi-cartridge saveset (directly, not over

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the net) as the XOR blocks are effectively ignored
until and unless needed for error recovery operations.
BACKUP likely will not be able to perform an XOR-based
recovery across reel or cartridge boundaries.

Unfortunately BACKUP can't read tapes over the network
because the RMS file attributes on a network task
access look wrong; the attributes reported include
variable length records.

_____________________________
5.42.6 How to perform a DoD security disk erasure?

Sometimes refered to as disk, tape, or media
declassification, as formatting, as pattern erasure,
or occasionally by the generic reference of data
remanence. Various references to the US Deparment of
Defence (DoD) or NCSC "Rainbow Books" documentation are
also seen in this context.

While this erasure task might initially appear quite
easy, basic characteristics of the storage media and
of the device error recovery and bad block handling
can make this effort far more difficult than it might
initially appear.

Obviously, data security and sensitivity, the costs
of exposure, applicable legal or administrative
requirements (DoD, HIPPA or otherwise), and the
intrinsic value of the data involved are all central
factors in this discussion and in the decision of the
appropriate resolution, as is the value of the storage
hardware involved.

With data of greater value or with data exposure
(sometimes far) more costly than the residual value
of the disk storage involved, the physical destruction
of the platters may well be the most expedient,
economical, and appropriate approach. The unintended
exposure of a bad block containing customer healthcare
data or of credit card numbers can quite be costly,
of course, both in terms of the direct loss, and the
longer-term and indirect costs of such exposures.

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Other potential options include the Freeware RZDISK
package, the OpenVMS INITIALIZE/ERASE command (and
potentially in conjunction with the $erapat system
service) and OpenVMS Ask The Wizard (ATW) topics
including (841), (3926), (4286), (4598), and (7320).
For additional information on sys$erapat, see the
OpenVMS Programming Concepts manual and the OpenVMS
VAX examples module SYS$EXAMPLES:DOD_ERAPAT.MAR. Some
disk controllers and even a few disks contain support
for data erasure. Some DSSI Disk ISEs, for instance.

For the prevention of casual disk data exposures,
a generic INITIALIZE/ERASE operation is probably
sufficient. This is not completely reliable,
particularly if the data is valuable, or if legal,
administrative or contractual restrictions are
stringent-there may well be revectored blocks that
are not overwritten or not completely overwritten by
this erasure, as discussed above, and these blocks can
obviously contain at least part of most any data that
was stored on the disk - but this basic disk overwrite
operation is likely sufficient to prevent the typical
information disclosures.

You will want to consult with your site security
officer, your corporate security or legal office, with
HP Services or your prefered service organization,
or with a firm that specializes in erasure or data
declassification tasks. HP Services does traditionally
offer a secure disk declassification service.

_____________________________
5.42.7 How to enable telnet virtual terminals?

To enable virtual terminal support for telnet and
rlogin devices, add the following logical name
definitions into SYLOGICALS.COM:

$ DEFINE/SYSTEM/EXECUTIVE TCPIP$RLOGIN_VTA TRUE
$ DEFINE/SYSTEM/EXECUTIVE TCPIP$TELNET_VTA TRUE

See SYS$STARTUP:SYLOGICALS.TEMPLATE for details on the
typical contents of SYLOGICALS.COM.

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System Management Information

In SYSTARTUP_VMS.COM, ensure that a command similar to
the following is invoked:

$ SYSMAN IO CONNECT VTA0/NOADAPTER/DRIVER=SYS$LOADABLE_IMAGES:SYS$TTDRIVER.EXE

In MODPARAMS.DAT, add the following line or (if already
present) mask the specified hexidecimal value into an
existing TTY_DEFCHAR2, and perform a subsequent AUTOGEN
with an eventual reboot:

TTY_DEFCHAR2 = %X20000

This value is TT2$M_DISCONNECT.

On older TCP/IP Services-versions prior to V5.0-you
will have to perform the following UCX command:

$ UCX
UCX> SET CONF COMM/REMOTE=VIRTUAL

_____________________________
5.42.7.1 Volume Shadowing MiniCopy vs MiniMerge?

MiniMerge support has been available for many years
with OpenVMS host-based volume shadowing, so long as
you had MSCP controllers (eg: HSC, HSJ, or HSD) which
supported the Volume Shadowing Assist known as "Write
History Logging".

If you are interested in mini-merge and similar
technologies, please see the Fibre Channel webpage
and the information available there:

o http://www.openvms.compaq.com/openvms/fibre/

Mini-Merge support was originally intended to be
controller-based and was expected with HSG80 series
storage controllers and was expected to require ACS 8.7
and OpenVMS Alpha V7.3-1.

Host-based Mini-Merge (HBMM) is now available for
specific OpenVMS releases via a shadowing ECO kit,
and is also present in OpenVMS V8.2 and later. HBMM
applies to the HSG80 series and-like host-based volume
shadowing-to most other (all other?) supported storage
devices.

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System Management Information

The following sections describe both Mini-Copy and
Mini-Merge, and can provide a basis for discussions.

_____________________________
5.42.7.1.1 Mini-Copy?

A Shadowing Full Copy occurs when you add a disk to an
existing shadowset using a MOUNT command; the entire
contents of the disk are effectively copied to the
new member (using an algorithm that goes through in
127-block increments and reads one member, compares
with the target disk, and if the data differs, writes
the data to the target disk and loops back to the
read step, until the data is equal for that 127-
block section). (This is one of the reasons why the
traditional recommendation for adding new volumes to
a shadowset was to use a BACKUP/PHYSICAL copy of an
existing shadowset volume, simply because the reads
then usually matched and thus shadowing usually avoided
the need for the writes.)

If you warn OpenVMS ahead of time (at dismount time)
that you're planning to remove a disk from a shadowset
but re-add it later, OpenVMS will keep a bitmap
tracking what areas of the disk have been modified
while the disk was out of the shadowset, and when you
re-add it later with a MOUNT command OpenVMS only has
to update the areas of the returned disk that the bit-
map indicates are now out-of-date. OpenVMS does this
with a read source / write target algorithm, which is
much faster than the shenanigans the Full Copy does,
so even if all of the disk has changed, a Mini-Copy is
faster than a Full Copy.

_____________________________
5.42.7.1.2 Mini-Merge?

A Shadowing Merge is initiated when an OpenVMS node
in the cluster (which had a shadowset mounted) crashes
or otherwise leaves unexpectedly, without dismounting
the shadowset first. In this case, OpenVMS must ensure
that the data is identical, since Shadowing guarantees
that the data on the disks in a shadowset will be
identical. In a regular Merge operation, Shadowing uses

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an algorithm similar to the Full Copy algorithm (except
that it can choose either of the members' contents
as the source data, since both are considered equally
valid), and scans the entire disk. Also, to make things
worse, for any read operations in the area ahead of
what has been merged, Shadowing will first merge the
area containing the read data, then allow the read to
occur.

A Merge can be very time-consuming and very I/O
intensive. If a node crashes, the surviving nodes can
query to determine what exact areas of the disk the
departed node was writing to just before the crash,
and thus Shadowing only needs to merge just those few
areas, so this tends to take seconds, as opposed to
potentially requiring many minutes or even hours for a
regular full Merge.

__________________________________________________________
5.43 Please explain DELETE/ERASE and File Locks?

DELETE/ERASE holds the file lock and also holds a
lock on the parent directory for the duration of the
erasure. This locking can obviously cause an access
conflict on either the file or on the directory-
it might well pay to rename files into a temporary
directory location before issuing the DELETE/ERASE,
particularly for large files and/or for systems with
multiple overwrite erase patterns in use; for any
systems where the DELETE/ERASE erasure operation will
take a while.

__________________________________________________________
5.44 Managing File Versions?

Some applications will automatically roll file
version numbers over, and some will require manual
intervention. Some will continue to operate without the
ability to update the version, and some will be unable
to continue. Some sites will specifically (attempt to)
create a file with a version of ;32767 to prevent the
creation of additional files, too.

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System Management Information

To monitor and resolve file versions, you can use
commands including:

$ SET FILE/VERSION_LIMIT=n filename
$ SET DIRECTORY/VERSION_LIMIT=n [directory]

And you can also monitor file version numbers, and
can report problems with ever-increasing file versions
to the organization(s) supporting the application(s)
generating files with ever-increasing version numbers
for details on potential problems, and for any
recommendations on resetting the version numbers for
the particular product or package. If required, of
course.

The following pair of DCL commands-though obviously
subject to timing windows- can be used to rename
all the versions of a file back down to a contiguous
sequence of versions starting at 1:

$ RENAME file.typ;* RENAME.TMP;
$ RENAME RENAME.TMP;* file.typ;

The key to the success of this RENAME sequence is the
specification of (only) the trailing semicolon on the
second parameter of each of the RENAME commands.

You may also see the numbers of files reduced with
DELETE commands, with multiple directories, or with
PURGE commands such as the following examples:

$ PURGE/BEFORE="-2-"
$ PURGE/BEFORE="TODAY-2-"
$ PURGE/KEEP=10"

You can use DFU (Freeware) to quickly and efficiently
scan for all files with large(r) version numbers:

DFU SEARCH/VERSION=MINIMUM=nnnn

If you are creating or supporting an application,
selecting temporary or log file filenames from among
a set of filenames-selecting filenames based on time,
on process id, on the day of week, week number, or
month, on the f$unique lexical (V7.3-2 and later), etc-
is often useful, as this approach more easily permits
on-line adjustments to the highest file versions and
easily permits on-line version compression using

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techniques shown above. With differing filenames,
you are less likely to encounter errors resulting
from files that are currently locked. You can also
detect the impending version number limit within the
application, and can clean up older versions and roll
the next file version creation to ;1 or such.

Also see Section 9.4.

__________________________________________________________
5.45 Host-based Volume Shadowing and RAID?

Host-based Volume Shadowing (HBVS) is Disk Mirroring is
RAID Level 1.

HBVS is capable of shadowing devices of different
geometries, of different block counts (with
dissimilar device shadowing; allowing for mixtures
of hardware) and-with dynamic volume expansion-of
growing volumes on the fly, and HBVS is capable of
shadowing/mirroring/raid-1 operations across cluster
configurations up to the full span-please see the
Cluster SPD for the current supported span; the
supported span limit is currently multiple hundreds
of kilometers-of a cluster. HBVS can be layered onto
controller (hardware) RAID, as well.

For information on host-based striping, please see the
StorageWorks RAID product.

5-67

_______________________________________________________

6 Information on Mail

__________________________________________________________
6.1 MAIL keeps saying I have new messages, but I don't. What do
I do?

if you see the %MAIL-W-NONEWMAIL, no new messages error
reported when MAIL indicates you have messages, then
the NEWMAIL count has become skewed from reality.

The count of new mail messages is kept separately
from your mail folder, and is stored in VMSMAIL_
PROFILE.DATA. It sometimes happens that this count
differs from what is stored in your mail folder. If
this arises, invoke MAIL and repeatedly enter the
READ/NEW command (or press the keypad hyphen key on
an LK-compatible keyboard) until you see no new mail
messages. Then enter the command one more time. This
will resynchronize the counters.

If you are operating in a cluster and find your mail
counts inconsistent across cluster members, your
customer is likely missing a definition of the VMSMAIL_
PROFILE logical name-and is probably also missing
definitions of other logical names associated with
other shared files-or has one or more inconsistent
definitions of this and likely of other logical names.

For details on the configuration data files that
must be shared within a cluster, please see
SYS$STARTUP:SYLOGICALS.TEMPLATE on V7.2 and later.

__________________________________________________________
6.2 How do I send or read attachments in VMS MAIL?

Is there any way to send or read mail with files as
attachments from VMS?

6-1

Information on Mail

Not directly with the OpenVMS MAIL facility, but there
are several other options:

o Install PINE, available commercially from Innosoft
or free from Andy Harper. With PINE you can both
send and receive MIME messages, if you have the
appropriate viewers available.

o http://www.process.com/

o http://www.agh.cc.kcl.ac.uk/files/vms/pine-vms/

o ftp://ftp2.kcl.ac.uk/pub/vms/pine-vms/

o If you are working from an X Windows display, you
can use the OpenVMS version of Netscape Navigator or
Mozilla. The mail download protocol chosen to access
the mail server from the Navigator or Mozilla mail
client can be POP or IMAP, with the former causing
messages to be downloaded while the latter permits
messages to be retained on the mail server. Most
folks prefer IMAP for this reason.

o MPACK/MUNPACK. To send a MIME mail, construct the
message with attachments manually using MPACK. You
cannot send the resulting file directly through MAIL
because an extra blank header line will be inserted
between your message and the OpenVMS MAIL headers,
which will cause the message to appear as plain text
in most mail programs. Some TCP/IP stacks provide
a work around for this problem, and if that doesn't
work, you should generally be able to force the
message directly into the SMTP port of your mail
machine. Examples of both methods are in:

o http://saf.bio.caltech.edu/pub/software/openvms/mmail.com

To read a MIME mail message, open it in MAIL,
extract it to a file, then use MUNPACK to break
out and decode the attachments.

MPACK/MUNPACK tools are also available on OpenVMS
Freeware V5.0.

o With OpenVMS V7.2 and later, use the MIME tool
supplied with OpenVMS.

6-2

Information on Mail

__________________________________________________________
6.3 How can I block SMTP mail relay spam?

Use the anti-spam capabilities present in the TCP/IP
Services V5.1 and later SMTP servers.

Use a firewall.

On earlier TCP/IP Services releases, some simple DCL
can reportedly prevent relay SMTP spam. Use the UCX
command SHOW SERVICE SMTP/FULL to find the directory
containing the UCX$SMTP_RECV_STARTUP.COM file, and
insert the following DCL:

$ !
$ ! Block spam.
$ !
$ MY_ADDRESS_LONG[0,32]=F$INTEGER(F$TRNLNM("SYS$REM_NODE")-"::")
$ MY_ADDRESS=F$FAO("!UB.!UB.!UB.!UB",F$CVUI(0,8,MY_ADDRESS_LONG),-
F$CVUI(8,8,MY_ADDRESS_LONG),F$CVUI(16,8,MY_ADDRESS_LONG),-
F$CVUI(24,8,MY_ADDRESS_LONG))'"
$ MY_ADDRESS_REVERSE=F$FAO("!UB.!UB.!UB.!UB",-
F$CVUI(24,8,MY_ADDRESS_LONG),F$CVUI(16,8,MY_ADDRESS_LONG),-
F$CVUI(8,8,MY_ADDRESS_LONG),F$CVUI(0,8,MY_ADDRESS_LONG))'"
$ WRITE SYS$OUTPUT F$TIME()+" "+F$TRNLNM("SYS$REM_NODE")+MY_ADDRESS
$ UCX SHOW HOST 'MY_ADDRESS_REVERSE'.INPUTS.ORBS.ORG
$ IF $STATUS.EQ.1
$ THEN
$ WRITE SYS$OUTPUT "SPAM from relay rejected"
$ EXIT
$ ENDIF
$ UCX SHOW HOST 'MY_ADDRESS_REVERSE'.SPAMSOURCES.ORBS.ORG
$ IF $STATUS.EQ.1
$ THEN
$ WRITE SYS$OUTPUT "SPAM source relay rejected"
$ EXIT
$ ENDIF
$ !
$ ! Run receiver.
$ !
$ run sys$system:ucx$smtp_receiver.exe
$ goto exit

6-3

_______________________________________________________

7 Information on Utilities

__________________________________________________________
7.1 How do I play an audio CD on my workstation?

If you've installed the DECwindows examples, you'll
find DECW$CDPLAYER.C, .DAT, .EXE, .UIL, and .UID.
Copy the .UID and .DAT files to DECW$USER_DEFAULTS:
(typically SYS$LOGIN:), define the logical name
DECW$CD_PLAYER to be the device name of your CD-ROM
drive (eg. DKA400:), give yourself PHY_IO and DIAGNOSE
privileges, and run the .EXE. (These privileges are
required, as the access to the CD-related extensions
will require the use of the privilege-protected IO$_
DIAGNOSE I/O function code.) You can also install
the image with these privileges. See the source for
additional details - note that the comments regarding
the need for SYSGEN CONNECT are no longer applicable
(at least as of VMS V5.5-2).

There's also SYS$EXAMPLES:CDROM_AUDIO.C and .EXE,
a non-Motif program, available on OpenVMS VAX, and
DECW$EXAMPLES:DECW$CDPLAYER.* on OpenVMS VAX and
OpenVMS Alpha.

The standard OpenVMS ATA (IDE) SYS$DQDRIVER device
driver does not support the necessary does not
support the necessary IO$_DIAGNOSE function code
that is required for access to audio CD media
commands (on OpenVMS versions prior to V7.3), but
an updated SYS$DQDRIVER device driver (source
code and all) with this capability and with the
source code of an updated DECW$CDPLAYER CD audio
player is available on the OpenVMS Freeware website
(www.hp.com/go/openvms/freeware/, look for the
directory /dqdriver/), and these updates are also
included on OpenVMS Freeware V5.0, and OpenVMS ECO
kits containing newer versions of the driver are
available. Freeware V6.0 has a version of DQDRIVER
that is newer than that of the OpenVMS Alpha V7.3-2

7-1

Information on Utilities

release, with additional capabilities and with improved
error diagnostics.

OpenVMS Alpha V7.3 and later include a version of
SYS$DQDRIVER with the necessary IO$_DIAGNOSE support.

__________________________________________________________
7.2 How do I access a Microsoft Windows floppy disk from
OpenVMS?

The HP Advanced Server (formerly known as PATHWORKS)
for OpenVMS product includes an unsupported and
undocumented utility called PCDISK, and this tool can
read and write various Microsoft MS-DOS and Microsoft
Windows FAT-format diskettes, and can usually access
FAT-format volumes written by other operating systems.

ProGIS in Germany sells a product called VMove which
supports DOS files on many different device types. For
more information, send mail to [email protected].

Engineering Software has a product called VAKSAT
which will read, write, and erase files on MS-DOS FAT
diskettes. Available for both VAX and Alpha. Contact
[email protected] for more information.

MadGoat PC Exchange (PCX) is a utility for copying
files to and from MS-DOS and Microsoft Windows (FAT)
format diskettes under OpenVMS, using an RX23 (3.5"),
RX26 (3.5"), or RX33 (5.25") diskette drive. For 3.5"
diskettes, high-density disks can be read or written;
double-density disks are read-only. Only high-density
disks are supported on the RX33.

o http://www.madgoat.com/

The Freeware package WINFX is available on Freeware
V6.0, and can read the FAT volume structure.

o http://www.hp.com/go/openvms/freeware/

7-2

Information on Utilities

__________________________________________________________
7.3 How do I play sound files on an AlphaStation? DECsound
doesn't work.

Various of the more recent AlphaStation systems use
a different sound board (Microsoft Sound System) than
the earlier DEC 3000 series systems, and DECsound,
as supplied by DECwindows Motif, doesn't support
this board nor this interface. HP offers an optional
product, Multimedia Services (MMOV) for OpenVMS:

o http://h18000.www1.hp.com/info/spd/

OpenVMS typically uses SPD 25.01.xx, SPD 41.87.xx,
and SPD 82.35.xx.

which provides a replacement for DECsound for this card
as well as many other features (an AVI and MPEG player,
video capture support, etc.)

Ensoniq sound support is also available.

__________________________________________________________
7.4 How do I read IBM EBCDIC tapes on OpenVMS?

Most (all?) IBM EBCDIC-based systems can read and write
ANSI-labeled ASCII magtapes. Fixed-length records
(MOUNT /FOREIGN /BLOCKSIZE=512 /RECORDSIZE=512, for
one-block records) and the DCL COPY command can be
used to transfer fixed-record-size text files out onto
tape media, or to read from fixed-record tape media.
Please consult the IBM documentation for the details
and command syntax needed when reading and writing ANSI
media using IBM JCL or other applicable IBM command
language.

There exists various freeware around (TAPECOPY, ETAPE,
TCOPY, MTEXCH) that can read and write EBCDIC tapes.
Visit the Encompasserve (DECUS) website software
archives search engine and search for "EBCDIC" for
details.

o http://www.encompassus.org

OpenVMS does not include an integrated tool for
EBCDIC tape processing, but does provide a character
conversion API useful within application programs.

7-3

Information on Utilities

One source for ETAPE is:

o http://www.ualr.edu/ftp/vms/ETAPE_SRC/

The OpenVMS Freeware V5.0 distribution included this
ETAPE tool, as well.

__________________________________________________________
7.5 How can I patch an OpenVMS Alpha image?

Using the OpenVMS Freeware tool ZAP:

o Look for the RMS_TOOLS directory on Freeware V5.0:
http://www.hp.com/go/openvms/freeware/

tell ZAP to read a block (bucket) of information
based on the virtual block number (VBN), using X for
hexadecimal. Dump yourself into the OpenVMS debugger
with R2 pointing into the buffer, EXAMINE/INSTRUCTION
as needed, alter the buffer as required, GO to get out
of the debugger and back into ZAP, and use the ZAP W
command to write the updated block.

7-4

_______________________________________________________

8 DCL Details

__________________________________________________________
8.1 DCL Symbols and OpenVMS Logical Names?

DCL symbols are programming-style variables implemented
within the DCL command interpreter, and these are
used both for programming and to provide command
verb synonyms. Symbols are local to the command
interpreter operating within a particular process,
and are not shared. Lists of symbols can be copied into
subprocesses during a subprocess creation operation,
but these symbols are neither copied back into the
parent process when the subprocess exits, nor are
symbols ever shared across processes.

Symbols can be specified in and utilized in basic
mathematical operations, and bit-level operations are
available with the f$cvsi and f$cvui bit extraction
lexical functions, and with the square-brackets
notation for bit insertion (see Section 8.13 for an
example), and with bitwise operators. Symbols are of
two basic types, STRING and INTEGER, and these (or an
undefined symbol) can be differentiated with the f$type
lexical function. DCL symbols can also be used as a
mechanism to abbreviate a DCL command verb, or an easy
way to invoke a DCL command procedure.

Symbols can have local or global scope within a
process, and scope is affected by nested procedure
calls and DCL constructs such as CALL and SET SCOPE,
but such discussions are beyond the scope of this
section.

OpenVMS Logical names can store device names, device
and directory specifications, rooted or searchlist
specifications, and full filenames. Logical names can
also store arbitrary data, but there are no native
mathematical or bitwise operators available. Analogous
to DCL symbols, process-local logical names can be
copied into subprocesses during a subprocess creation

8-1

DCL Details

operation, but these process-local logical names are
neither copied back into the parent process when the
subprocess exits, nor are these logical names ever
shared.

Logical names are implemented deep within the OpenVMS
executive, and are organized into logical name tables.
Logical names can be stored in tables private to a
process( LNM$PROCESS, the process-local logical name
table) , that can be shared among processes in the same
job tree ( LNM$JOB, the job logical name table) or in
logical name tables that are shared among larger groups
of processes (eg: LNM$GROUP, the UIC group logical
name table and LNM$SYSTEM, the system-wide logical name
table). Logical names are centrally intended to provide
various I/O-related capabilities, including device
independence and configuration customization-correctly-
written application programs can use logical names to
avoid embedding specific device or device and directory
specifications, and to allow filename and configuration
customizations.

One of the most powerful capabilities of logical names
beyond the device independence provided involves the
defaulting capabilities; you can use RMS parsing
(directly, or with mechanisms such as the f$parse
lexical function) to provide a filename and a default
filename. To provide the mechanism that allows SYSUAF
to be located in an arbitrary position or even an
arbitrary filename, a construct similar to the
following is used:

$ UAF = F$PARSE("SYSUAF","SYS$SYSTEM:.DAT")

This design allows the logical name SYSUAF to be
optionally defined, and - when present-to specify the
particular location and name of the file. Portions
of the full file specification that are omitted are
retrieved using the default translation of SYS$SYSTEM:
and the file type of .DAT.

Logical names also have assigned processor modes, as
some translations must be trustworthy. In the example
above, only trusted and privileged system users should
be able to redirect the SYSUAF authorization database,

8-2

DCL Details

so any definition of the SYSUAF logical name must be
made in EXECUTIVE mode in a trusted logical name table.

As for common OpenVMS terminology, logical names are
"defined" and the associated processing is refered to
as "translation", while symbols are "equated" and the
associated processing is refered to as "substitution".
"Lexical functions" are processing routines built
into DCL, and typically prefixed with f$. Many of the
lexical functions are built upon correspondingly-named
system services, though not all.

Symbol substitution occurs only when the DCL command
interpreter is reading and processing the command
input; for information on DCL symbol substitution, see
Section 8.10. For program access, see the RTL routines
lib$set_symbol and lib$get_symbol.)

For information on logical name translation, please see
f$trnlnm lexical function and the DCL commands DEFINE
and DEASSIGN, as well as underlying system services
such as sys$trnlnm. Logical name translation occurs
when requested, or as the file or I/O operation is
started.

Please see the OpenVMS User's Guide in the OpenVMS
documentation set for a far more detailed description
of these constructs.

For related materials, please see Section 8.10 and
Section 8.11.

__________________________________________________________
8.2 How do I run a program with arguments?

The RUN command does not accept arguments. To pass
arguments to a program, you must use what is called
a "foreign command", and either an explicit command
as shown here, or an automatic foreign command. For
example:

$ unzip :== $disk:[dir]unzip.exe
$ unzip -?

8-3

DCL Details

The leading $ in the equivilence name for the symbol
definition is what makes the DCL symbol a foreign
command. If the device and directory are omitted,
SYS$SYSTEM: is assumed.

Under OpenVMS V6.2 and later, DCL supports automatic
foreign command definition via the logical name
DCL$PATH. An example of a definition of this logical
name is:

$ DEFINE DCL$PATH SYS$DISK:[],ddcu:[mytooldir],SYS$SYSTEM:

DCL will first look for a command in the DCL command
table, and if no match is found and if DCL$PATH is
defined, it will then look for command procedures and
executable images with filenames matching the command
specified, in the directories specified via DCL$PATH.
The first match found is invoked, and under OpenVMS,
the DCL$PATH support will cause a command procedure to
be activated in preference to an executable image.

For more information on foreign commands or on
automatic foreign command support, see the OpenVMS
User's Manual.

See also Section 10.3.

If you want to create a detached process that takes
arguments from a command line, it must be run under the
control of a command line interpreter (CLI) (typically
DCL). This is done by placing the command line in a
file, specifying SYS$SYSTEM:LOGINOUT.EXE as the image
to run and the command file as the input. For example:

$ OPEN/WRITE CMD TEMP_INPUT.COM
$ WRITE CMD "$ MYCOMMAND arguments"
$ CLOSE CMD
$ RUN/DETACHED SYS$SYSTEM:LOGINOUT /INPUT=TEMP_INPUT.COM

Various OpenVMS library calls (such as lib$spawn(),
cli$dcl_parse(), and the C library system() call)
require access to a command line interpreter such as
DCL to perform requested actions, and will not operate
if a CLI is not available.

8-4

DCL Details

When a CLI is not available, these calls typically
return the error status SS$_NOCLI. And as mentioned
above, invoke the image LOGINOUT to cause a CLI (such
as DCL) to be mapped into and made available in the
context of the target process.

For examples of how TCP/IP Services sets up its foreign
commands (which includes tools such as uuencode
and uudecode), please see the DCL command procedure
SYS$STARTUP:TCPIP$DEFINE_COMMANDS.COM.

Also see Section 8.12.

__________________________________________________________
8.3 How can I clear the screen in DCL?

The simplest way is the TYPE/PAGE NLA0: command.

You can set up a symbol to clear the screen in your
LOGIN.COM:

$ CLS :== TYPE/PAGE NLA0:

__________________________________________________________
8.4 Using REPLY/LOG from DCL? Disabling Console OPCOMs?

Your terminal must be enabled as an operator terminal
before the REPLY/LOG command can be used, but a DCL
procedure (batch command file, system startup, etc)
does not have an associated terminal. To make this
work, use the following sequence to enable the OPA0:
console as the operator terminal, then the REPLY/LOG
command will be accepted:

$ DEFINE/USER SYS$COMMAND _OPA0:
$ REPLY/LOG
$ DEFINE/USER SYS$COMMAND _OPA0:
$ REPLY/ENABLE

To disable the system console terminal (OPA0:) as an
operator terminal, use the following command:

$ DEFINE/USER SYS$COMMAND _OPA0:
$ REPLY/DISABLE

8-5

DCL Details

Also see SYLOGICALS.COM (and SYLOGICALS.TEMPLATE) for
information on configuring the behaviour of OPCOM,
including the (default) use of the system console
(OPA0:) as an operator terminial and the specific
contents and behaviour of the system operator log file
OPERATOR.LOG.

__________________________________________________________
8.5 How do I generate a random number in DCL?

With V7.3-2 and later, f$unique can be useful
here. Alternatively, here is a pseudo-random number
generator, just do a GOSUB RAND and the global symbol
RANDOM will contain a randomly generated number. You
can feed the generator a ceiling value (__CEIL) or a
new seed (__SEED).

$! RAND - returns a positive random number ("RANDOM") between 0 and
$! __CEIL - 1.
$! sharris-at-sdsdmvax.fb3.noaa.gov
$ RAND:
$
$ IF F$TYPE(__SEED) .EQS. ""
$ THEN
$ ! seed the random number generator, ...
$ __NOW = F$CVTIME()
$ __HOUR = 'F$EXTRACT(11,2,__NOW)'
$ __MINUTE = 'F$EXTRACT(14,2,__NOW)'
$ __SECOND = 'F$EXTRACT(17,2,__NOW)'
$ __TICK = 'F$EXTRACT(20,2,__NOW)'
$
$ __SEED == __TICK + (100 * __SECOND) + (6000 * __MINUTE) + -
(360000 * __HOUR)
$ ! the generator tends to do better with a large, odd seed, ...
$ __SEED == (__SEED .OR. 1)
$ ! clean up, ...
$ DELETEX/SYMBOL __NOW
$ DELETEX/SYMBOL __HOUR
$ DELETEX/SYMBOL __MINUTE
$ DELETEX/SYMBOL __SECOND
$ DELETEX/SYMBOL __TICK
$ ENDIF
$
$ IF F$TYPE(__CEIL) .EQS. "" THEN __CEIL = %X3FFFFFFF

8-6

DCL Details

$
$ __SEED == __SEED * 69069 + 1
$
$ RANDOM == (__SEED.AND.%X3FFFFFFF)/(%X40000000/__CEIL)
$
$ RETURN

__________________________________________________________
8.6 What does the MCR command do?

The MCR is an artifact of RSX compatibility mode, the
operating system from which OpenVMS is descended. MCR
is the Monitor Console Routine, and the command is
intended to activate RSX compatibility mode utilities.
When used on OpenVMS, the command is most commonly
used to run the specified image and-because the tool
detects the image is not a compatibility-mode image-
it acts as a form of RUN command with the default
file specification of SYS$SYSTEM:.EXE. MCR passes any
(optional) command line arguments in a fashion similar
to a foreign command. In other words:

$ MCR FOO BAR

is equivalent to:

$ FOO :== $FOO
$ FOO BAR

MCR is not documented. Use of a foreign command or the
DCL$PATH mechanism is preferred. For details on this,
see Section 8.2.

__________________________________________________________
8.7 How do I change the OpenVMS system prompt?

You can use the SET PROMPT command for this purpose.
SET PROMPT sets the DCL prompt to the specified string.

When you want to display variable information, you
will need to establish a tie-in that provides the
information to the SET PROMPT command as required.

If you wish to display the default directory for
instance, you will have to establish a tie between
the SET DEFAULT command and the SET PROMPT commands, as
there is no direct way to get the default directory as

8-7

DCL Details

the DCL prompt. You can easily acquire or create a set
of DCL command procedures that perform the SET DEFAULT
and SET PROMPT for you. These DCL command procedures
often use a command such as:

$ set prompt='f$environment("default")'

More advanced users could implement a system service or
other intercept, and use these tools to intercept the
directory change and reset the prompt accordingly.
(This approach likely involves some kernel-mode
programming, and requires write access to various
undocumented OpenVMS data structures.)

There are related tools available from various sources,
including the following web sites:

o ftp://ftp.hhs.dk/pub/vms/setpmt/

o ftp://ftp.tmesis.com/sys_service_hook.src

o James F. Duff has also made available a Macro32 tool
known as TIME_PROMPT, a tool that sets the prompt to
the current system time.

o Many folks have contributed DCL procedures to
perform this task. Visit the newsgroup archives
for information and examples.

__________________________________________________________
8.8 Can I do DECnet task-to-task communication with DCL?

Yes, you can do this with DCL.

The OpenVMS DECnet documentation shows various simple
examples using the task object and the TYPE command to
trigger the execution of a DCL command procedure on a
remote node. An example DCL command procedure that is
rather more advanced than using the TYPE command as a
trigger is included in the Ask The Wizard area:

o http://www.hp.com/go/openvms/wizard/

For additional information on the OpenVMS Ask The
Wizard (ATW) area and for a pointer to the available
ATW Wizard.zip archive, please see Section 3.8.

8-8

---------------------------- #include <rtfaq.h> -----------------------------
For additional, please see the OpenVMS FAQ -- www.hp.com/go/openvms/faq
--------------------------- pure personal opinion ---------------------------
Hoff (Stephen) Hoffman OpenVMS Engineering hoff[at]hp.com