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HP OpenVMS DCL Dictionary

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If you specify more than one function, separate each with a comma and enclose the list in parentheses. If you specify no functions in the /SHOW qualifier, it increments the listing level count; the /NOSHOW qualifier decrements the count in similar circumstances. Because these qualifiers contribute to the listing file, you must also specify the /LIST qualifier when you use them. If you do not specify the /SHOW qualifier, the MACRO command assumes a default of /SHOW=(CONDITIONALS,CALLS,DEFINITIONS). If you specify only one function, you can omit the parentheses.



Positional qualifier. The /UPDATE qualifier cannot be used with the /ALPHA, /LIBRARY, or /MIGRATION qualifier.

Updates the input file it qualifies by using the SUMSLP batch editor and the specified update file or files. By default, the assembler assumes that the update file has the same file name as the input source file and a file type of .UPD. You cannot include the asterisk (*) and the percent sign (%) wildcard characters in the file specifications. If it cannot find a specified update file, the assembler prints an informational message and continues the assembly.

If you specify only one update file, you can omit the parentheses. If you specify more than one update file, the assembler merges the contents into a single list of updates before applying the updates to the source file.

The /NOUPDATE qualifier has the same effect as not specifying the /UPDATE qualifier, or negates any /UPDATE qualifiers specified earlier in the command line. The input source file and update files are not changed by the update operation. The effects of the update appear in the compiled output. If you specify the /LIST qualifier with the /UPDATE qualifier, the assembler writes an audit trail of the changes to the listing file.




In this example, the MACRO command requests two separate assemblies. Using MAR as the default file type, MACRO assembles CYGNUS.MAR to produce CYGNUS.LIS and CYGNUS.OBJ. Then it assembles LYRA.MAR and creates a listing file named LYRA.LIS and an object module named LYRAN.OBJ. The default output file type for a listing is .LIS.

The command requests the search of the MYLIB library file in the current directory for macro definitions.



MACRO assembles the file ORION.MAR and creates an object file named ORION.OBJ. Executing the command in a batch job causes MACRO to create a listing file named ORION.LIS.



MACRO concatenates the files ALPHA.MAR and BETA.MAR to produce an object file named ALPHA.OBJ and a listing file named ALPHA.LIS. The command line requests the search of libraries MYLIB.MLB (in the current default directory) and OLDLIB.MLB (in the directory [TEST]) for macro definitions. When macro calls are found in BETA.MAR, MACRO searches the libraries OLDLIB, MYLIB, and the system library STARLET.MLB, in that order, for the definitions.

The PRINT command prints the listing file ALPHA.LIS.



MACRO requests two separate assemblies. MACRO searches TESTLIB.MLB and the system library STARLET.MLB for macro definitions when macro calls are found in DELTA.MAR, and searches MYLIB.MLB and the system library STARLET.MLB for macro definitions when macro calls are found in ALPHA.MAR.


Invokes the Mail utility, which is used to send messages to other users of the system.

For more information about the Mail utility, refer to the OpenVMS User's Manual or online help.


MAIL [filespec] [recipient-name]


Invokes the Sort/Merge utility, which combines 2 to 10 similarly sorted input files and creates a single output file. Note that input files to be merged must be in sorted order.

For more information about the Sort/Merge utility, refer to the OpenVMS User's Manual or online help.


MERGE input-filespec1,input-filespec2[,...] output-filespec


Invokes the Message utility, which compiles one or more files of message definitions.

For more information about the Message utility, refer to the OpenVMS Command Definition, Librarian, and Message Utilities Manual or online help.


MESSAGE filespec[,...]


Invokes the Monitor utility, which monitors classes of systemwide performance data at a specified interval.

For more information about the Monitor utility, refer to the HP OpenVMS System Management Utilities Reference Manual or online help.


MONITOR [/qualifier[,...]] classname[,...] [/qualifier[,...]]


The Mount command (MOUNT) is used to make a disk or magnetic tape available for processing.


MOUNT device-name[:][,...] [volume-label[,...]] [logical-name[:]]



Specifies the physical device name or logical name of the device on which the volume is to be mounted. On a system where volumes are not connected to HSCs (hierarchical storage controllers), use the following format:

The dd describes the device type of the physical devices used. For example, an RA60 disk drive is device type DJ, and an RA80 or RA81 disk drive is device type DU. The c identifies the controller, and the u identifies the unit number of the device.

On a system with HSCs, use one of the following formats:


If your devices are dual ported to HSCs, use the allocation-class format. For example, $125$DUA23 represents an RA80 or RA81 disk with unit number 23. The disk's allocation class is $125$. The c part of the format is always A for HSC disks. TROLL$DJA12 represents an RA60 disk with unit number 12. The device is connected to an HSC named TROLL. Refer to OpenVMS Cluster Systems for more information about naming conventions.

Device names can be generic so that if no controller or unit number is specified, the system attempts to mount the first available device that satisfies those specified components of the device names. If no volume is physically mounted on the specified device, MOUNT displays a message requesting that you place the volume in the device; after you place the volume in the named drive, MOUNT then completes the operation.

If you specify more than one device name for a disk or magnetic tape volume set, separate the device names with either commas or plus signs. For a magnetic tape volume set, you can specify more volume labels than device names or more device names than volumes.


Specifies the label on the volume.

The number of characters allowed in a label depends on the type of device, as follows:

Device Type Number of Characters
in Label
Magnetic tape 0-6
Files-11 disk 1-12
ISO 9660 disk 1-32

OpenVMS requires disk volume labels to be unique in the first 12 characters within a given domain. For example, disks mounted by different members of the same group using the /GROUP qualifier must be unique. However, disks mounted in different domains, such as one mounted using the /GROUP qualifier and one mounted privately, can use the same volume label.

If you mount an ISO 9660 volume using the /SYSTEM or /CLUSTER qualifier, and the volume label is not unique within the first 12 characters, you must supply an alternate volume label using the qualifier /OVERRIDE=IDENTIFICATION. If you choose this option, then Mount verification is disabled for the device.

In addition, if a volume is part of a volume set and the first 12 characters of the volume-set name are the same as the first 12 characters of the volume label, a lock manager deadlock will occur. To avoid this problem, you must override either the volume label (by using the /OVERRIDE qualifier) or the volume-set name (by using the /BIND qualifier).

If you specify more than one volume label, separate the labels with either commas or plus signs. The volumes must be in the same volume set and the labels must be specified in ascending order according to relative volume number.

When you mount a magnetic tape volume set, the number of volume labels need not equal the number of device names specified. When a magnetic tape reaches the end-of-tape (EOT) mark, the system requests the operator to mount the next volume on one of the devices. The user is not informed of this request; only the operator is informed.

When you mount a disk volume set, each volume label specified in the list must correspond to a device name in the same position in the device name list.

The volume-label parameter is not required when you mount a volume with the /FOREIGN or /NOLABEL qualifier or when you specify /OVERRIDE=IDENTIFICATION. To specify a logical name when you enter either of these qualifiers, type any alphanumeric characters in the volume-label parameter position.


Defines a 1- to 255-alphanumeric character string logical name to be associated with the volume.

If you do not specify a logical name, the MOUNT command assigns the default logical name DISK$volume-label to individual disk drives; it assigns the default logical name DISK$volume-set-name to the device on which the root volume of a disk volume set is mounted. Note that if you specify a logical name in the mount request that is different from DISK$volume-label or DISK$volume-set-name, then two logical names are associated with the device.

If you do not specify a logical name for a magnetic tape drive, the MOUNT command assigns only one logical name, TAPE$volume-label, to the first magnetic tape device in the list. No default logical volume-set name is assigned in this case.

The MOUNT command places the name in the process logical name table, unless you specify /GROUP or /SYSTEM. In the latter cases, it places the logical names in the group or system logical name table.

If you specify the /CLUSTER qualifier, the logical name is established on each node in the cluster.


Avoid assigning a logical name that matches the file name of an executable image in SYS$SYSTEM. Such an assignment prohibits you from invoking that image.

Do not use the logical name assigned to a volume as a distributed file system (DFS) access point. If you attempt to add a DFS access point using the same name as the logical name, DFS fails as in the following example:

%DNS-W-NONSNAME, Unknown namespace name specified

If the logical name of a volume is in a process-private table, then the name is not deleted when the volume is dismounted.


The Mount command (MOUNT) is used to make a disk or magnetic tape available for processing. MOUNT allows you to ensure that the device has not been allocated to another user, that a volume is physically loaded on the device specified, and that the label on the volume matches the label specified. For magnetic tape volumes, MOUNT also checks the volume accessibility field of the VOL1 label.

Normally, MOUNT allocates the device to the user who enters the command. However, mounting volumes with the /SHARE, /GROUP, or /SYSTEM qualifier deallocates the device, because the purpose of these qualifiers is to make the volume shareable.


To mount a volume on a device, you must have read (R) or control (C) access to that device.

Any subprocess in the process tree can mount or dismount a volume for the job. When a subprocess mounts a volume (for the job) as private, the master process of the job becomes the owner of this device. This provision is necessary because the subprocess may be deleted and the volume should remain privately mounted for this job. However, when a subprocess explicitly allocates a device and then mounts a private volume on this device, the subprocess retains device ownership. In this situation, only subprocesses with SHARE privilege have access to the device.

Upon successful completion of the operation, MOUNT notifies you with a message sent to SYS$OUTPUT. If the operation fails for any reason, MOUNT notifies you with an error message.

Certain file utilities such as MOUNT allocate virtual memory to hold copies of the index file and storage bitmaps. Beginning with larger bitmaps in OpenVMS Version 7.2, the virtual memory requirements of these utilities increase correspondingly. To use MOUNT on volumes with large bitmaps, you might need to increase your page file quota. On OpenVMS VAX systems, you might also need to increase the system parameter VIRTUALPAGECNT. The virtual memory size is shown as VAX pages (or Alpha 512-byte pagelets) per block of bitmap. Note that the size of the index file bitmap in blocks is the maximum number of files divided by 4096. The virtual memory requirements for MOUNT is equal to the sum of the sizes of all index file bitmaps and storage bitmaps on the volume set. This requirement applies to MOUNT only if you rebuild a volume.

If you have a disk volume that you do not want the file system to cache, such as a database volume, use the /NOCACHE qualifier. This disables caching for the volume:

  • It stops the following metadata caches from caching any metadata for the volume on the local node:
    The Extent Cache
    The File Identifier Cache
    The Quota Cache
  • It stops the local Extended File Cache or Virtual I/O Cache from caching any files in the volume.

MOUNT Usage Summary

The Mount command (MOUNT) makes a disk or magnetic tape volume available for processing.

To invoke MOUNT, enter the DCL command MOUNT, followed by the device name, volume label, and logical name. You must include a device name and a volume label (unless you specify /OVERRIDE=IDENTIFICATION or use the /FOREIGN or /NOLABEL qualifier); the logical name is optional.

MOUNT returns you to the DCL level after it either successfully completes the operation or fails, generating an error message. If you press Ctrl/Y or Ctrl/C, MOUNT aborts the operation and returns you to the DCL prompt.

You can direct output from MOUNT operations with the /COMMENT and /MESSAGE qualifiers. When the mount operation requires operator assistance, use /COMMENT to specify additional information to be included with the operator request. The /COMMENT text string is sent to the operator log file and to SYS$OUTPUT. The string must contain no more than 78 characters.

Use the /MESSAGE qualifier (this is the default) to send mount request messages to your current SYS$OUTPUT device. If you specify /NOMESSAGE during an operator-assisted mount, messages are not sent to SYS$OUTPUT; the operator sees them, however, if an operator terminal is enabled to receive messages.

Many MOUNT qualifiers require special privileges. Some qualifiers require different privileges according to which qualifier keyword you specify. See the individual qualifiers for details. The following table lists MOUNT qualifiers that require special privileges:

Qualifier Keywords Required Privilege
  SAME:device OPER
  file-spec OPER and CMKRNL

1Or your UIC must match the volume UIC.



Specifies, for ODS-1 disk volumes, the approximate number of directories that will be in use concurrently on the volume. (The /ACCESSED qualifier is meaningless for ODS-2 volumes.)

Specify a value from 0 to 255 to override the default that was specified when the volume was initialized.

You need the user privilege OPER to use /ACCESSED.


The following command requests the volume labeled WORK to be mounted on DKA1, specifying 150 as the number of active directories on the volume:


/ASSIST (default)


Directs the mount operation to allow operator or user intervention if the mount request fails.

When you specify the /ASSIST qualifier, MOUNT notifies the user and certain classes of operator if a failure occurs during the mount operation. If a failure occurs, the operator or user can either abort the operation or correct the error condition to allow the operation to continue.

The operator-assist messages are sent to all operator terminals that are enabled to receive messages; magnetic tape mount requests go to TAPE and DEVICE operators, and disk mount requests go to DISK and DEVICE operators. Thus, if you need operator assistance while mounting a disk device, a message is sent to DISK operators. See the description of the REPLY command for more information about enabling and disabling operator terminals.

Any operator reply to a mount request is written to SYS$OUTPUT to be displayed on the user's terminal or written in a batch job log.

If no operator terminal is enabled to receive and respond to a mount assist request, a message is displayed informing the user of the situation. If a volume is placed in the requested drive, no additional operator response is necessary. If the mount request originates from a batch job and no operator terminal is enabled to receive messages, the mount is aborted. Refer to the OpenVMS System Messages: Companion Guide for Help Message Users for a description of the error messages and their suggested user actions.

The default is /ASSIST and can be overridden by /NOASSIST.


The following command mounts an HSG80 Fibre Channel disk volume labeled DOC and assigns the logical name WORK. The /NOASSIST qualifier signals MOUNT that no operator intervention is necessary.

%MOUNT-I-MOUNTED, DOC         mounted on _$1$DGA0: (NODE)

/AUTOMATIC (default)


Determines whether MOUNT enables or disables automatic volume switching and labeling for magnetic tape or ISO 9660 CD-ROM.

Magnetic Tape

If you have multiple magnetic tape drives allocated to a volume set, the magnetic tape ancillary control process (MTACP) performs the volume switch by sequentially selecting the next available drive allocated to the volume set. The MTACP expects the next reel of the volume set to be loaded on that drive.

If the MTACP is writing to the volume set, it creates a label and initializes the magnetic tape with that label and the protections established for the first magnetic tape of the volume set. If it is reading from the volume set, the MTACP generates the label and attempts to mount the next magnetic tape with that label. If the drive has the wrong magnetic tape (or no magnetic tape) loaded, the MTACP sends a message to the operator's console to prompt for the correct magnetic tape.

The label generated by the MTACP fills the 6-character volume identifier field. The first four characters of the field contain the first four characters of the label specified in the MOUNT command, padded with underscores when the label is not at least four characters. The fifth and sixth characters contain the relative volume number for this reel in the volume set.

If you specify /NOAUTOMATIC, the MTACP requires operator intervention to switch to the next drive during end-of-tape processing, and requires that the operator specify a label for each new reel added to a volume set.


Under ISO 9660, not all volume-set members must be mounted to perform I/O operations against that volume set. By default, if I/O operations attempt to access an unmounted volume-set member, an operator message is sent to all DISK CLASS operators for system-mounted volume sets, or the owning process for privately mounted volume sets. The message specifies the volume-set member to mount to complete the I/O operation requested. If /NOAUTOMATIC is specified, then an I/O operation to a nonmounted volume set member completes with an error message SS$_DEVNOTMOUNT.


The following command instructs MOUNT not to generate its own label for the second volume, but to use the ones supplied with the MOUNT command instead. If the second volume is not already labeled, then the operator must use REPLY/INIT and supply the second label.



Creates a volume set of one or more disk volumes or adds one or more volumes to an existing volume set.

The parameter, volume-set-name, specifies a 1- to 12-alphanumeric-character name identifying the volume set.

An ISO 9660 volume-set name can be from 1 to 128 characters in length.

OpenVMS requires volume-set names to be unique in the first 12 characters. In addition, if the first 12 characters of volume-set name are the same as the first 12 characters of any volume label, a lock manager deadlock will occur. To avoid this problem, you must override either the volume label (by using the /OVERRIDE qualifier) or the volume-set name (by using the /BIND qualifier).

You must specify the /BIND qualifier when you first create the volume set or each time you add a volume to the set. To dismount an individual volume of the volume set, you must use the DISMOUNT qualifier /UNIT; otherwise, dismounting an individual volume dismounts the entire volume set.

When you create a volume set, the volumes specified in the volume-label list are assigned relative volume numbers based on their positions in the label list. The first volume specified becomes the root volume of the set.

When you add a volume or volumes to a volume set, the first volume label specified must be that of the root volume, or the root volume must already be on line.

Note that if you attempt to create a volume set from two or more volumes that already contain files and data, the file system does not issue an error message when you issue the MOUNT/BIND command. However, the volumes are unusable as a volume set because the directory structures are not properly bound.

If you mount an ISO 9660 volume using the /SYSTEM or /CLUSTER qualifier, and the volume label is not unique within the first 12 characters, you must supply an alternate 12-character volume label using the qualifier /BIND=volume-set-name. If you choose this option, then Mount verification is disabled for the device.


Once a volume is bound into a volume set, it cannot easily be unbound. To unbind a bound volume set (BVS):
  1. Do an image backup of the BVS.
  2. Initialize all volumes of the BVS.
  3. Do an image restore to a single volume with the /NOINITIALIZE qualifier, or do a nonimage restore to a single volume.


The following command creates a volume set named LIBRARY. This volume set consists of the volumes labeled BOOK1, BOOK2, and BOOK3, which are mounted physically on devices DMA0, DMA1, and DMA2, respectively.

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