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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 See the source for additional details - note that the comments regarding the need for SYSGEN CONNECT are no longer applicable (at least as of VMS V5.5-2).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 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.
ProGIS in Germany sells a product called VMove which supports DOS files on many different device types. For more information, send mail to info@progis.de.
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 ed@cityscape.co.uk 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.
The Freeware package WINFX is available on Freeware V6.0, and can read the FAT volume structure.
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:
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 Why is DECmigrate not working with Fortran?
%OTS-F-INDATCOR internal data corrupted in Run-time Library |
This error can arise with Fortran programs if you are running a recent version of OpenVMS Alpha, and are using DECmigrate to translate Fortran applications. The DECmigrate Run-Time Library attempts to support mixed translated-native I/O to the same unit by sharing the native Fortran RTL's internal data structures, and in OpenVMS 7.2 these structures changed and the translated RTL was not updated accordingly.
You can copy DEC$FORRTL.EXE from OpenVMS 7.1, copying it to some spare directory, and then defining the logical name DEC$FORRTL to point to it before running your translated application. Or rebuilding the application to use the available native Fortran compiler. Or you can apply the current Fortran RTL kit, which has a fix for this.
Also check for upgrades to DECmigrate (VEST and AEST) environments. See
Section 13.12 for details. For DECmigrate-related PL/I information, see
Section 13.3.
7.5 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.
OpenVMS does not include an integrated tool for EBCDIC tape processing, but does provide a character conversion API useful within application programs.
One source for ETAPE is:
The OpenVMS Freeware V5.0 distribution included this ETAPE tool, as
well.
7.6 How can I patch an OpenVMS Alpha image?
Using the OpenVMS Freeware tool ZAP:
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.
The RUN command does not accept arguments. To pass arguments to a program, you must use what is called a "foreign command". For example:
$ unzip :== $disk:[dir]unzip.exe $ unzip -? |
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$dcl_parse(), and the C library system() call) require access to a command line interpreter such as DCL to perform requested actions, and will not operate if a CLI is not available.
When a CLI is not available, these calls typically return the error status SS$_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 8.10.
8.2 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: |
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 |
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.
8.4 How do I generate a random number in DCL?
Here is a 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
$
$ __SEED == __SEED * 69069 + 1
$
$ RANDOM == (__SEED.AND.%X3FFFFFFF)/(%X40000000/__CEIL)
$
$ RETURN
|
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 8.1.
8.6 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 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:
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:
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 3.9.
DCL does not include support asynchronous I/O, thus a predetermined
protocol or a predetermined "turn-around" command sequence must be
implemented in order to avoid protocol deadlocks---cases where both
tasks are trying to write or both tasks are trying to read. The task
that is writing messages to the network must write (or write and read)
a predetermined sequence of messages, or it must write a message that
tells the reader that it can now start writing messages. (This is the
essence of a basic half-duplex network protocol scheme.)
8.8 How can I get the width setting of a terminal?
$ width = f$getdvi(terminal,"DEVBUFSIZ") |
Use DCL ampersand substitution, and not apostrophe substitution.
$ pipe show system | search sys$input opcom | (read sys$input pid ;
pid=f$element(0," ",pid) ; define/system opcom_pid &pid)
$ show log opcom_pid
"OPCOM_PID" = "0000020B" (LNM$SYSTEM_TABLE)
|
With a command to create a detached process such as:
$ RUN/DETACHED SYS$SYSTEM:LOGINOUT /INPUT=TEMP_INPUT.COM |
If you are trying to use a logical name as the /INPUT, /OUTPUT or /ERROR on a RUN/DETACH command, then you must translate the logical name specifications to physical references before passing them, or the definitions must reside in a logical name table that is visible to the newly-created process.
Also note that LOGINOUT only creates the SYS$LOGIN, SYS$LOGIN_DEVICE, and SYS$SCRATCH logical names if it is processing a login that is based on the contents of a SYSUAF record---without access to the associated SYSUAF record, this information is not available to LOGINOUT. (If you want to see these particular logical names created, then please specify the /AUTHORIZE qualifier on the RUN/DETACHED command.)
If you do not specify LOGINOUT as the image, then there is no easy way to get these logical names. Also, any logical names that are used in the target image file specification must also be in a logical name table accessible (by default) by the newly-created detached process. Shared tables include the group (if the process is in the same UIC group) and the system table. (If the target process is to be in another UIC group, a suitablly privileged user or application can create the necessary logical name(s) directly in the other group logical name table.)
When in doubt, create a short DCL command file as input, and use a SHOW LOGICAL and similar commands to examine the context. (And use physical device and directory references on the RUN/DETACH of the LOGINOUT image, when specifying this command file as /INPUT.) Also remember to check both security auditing and system accounting when troubleshooting problems with the RUN/DETACH.
Also see Section 8.1.
8.11 How to use escape and control characters in DCL?
To write a message and then the bell character, use:
$ bell[0,7] = 7 $ write sys$output "Hello''bell'" |
To write blinking text, use:
$ esc[0,7] = 27 $ text = "Blinking Text" $ write sys$output "''esc'[5m''text'''esc'[m" |
Also see sections Section 11.6, Section 12.1.
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