Updated: 11 December 1998

OpenVMS System Manager's Manual

You can enable auditing for the volume object class; the system then audits disk volume access, with the following exceptions:

• The system does not audit volume creation or deletion.
• The system does not audit access for tapes, ODS-1, or foreign-mounted volumes.

Mounting a disk or tape volume establishes a relationship between the volume and the device on which the volume is physically loaded. After you mount a volume, the system knows it exists, and users can access it. (This section assumes that you are performing the mount operation yourself.)

File-Structured and Foreign Volumes

Ordinarily, when you mount volumes, the system imposes a format on each volume that allows you to read, write, create (or execute), and delete files. These mounted volumes have the format of the OpenVMS operating system.

If you specify the /FOREIGN qualifier when you mount a volume, the system does not impose a format on the media, and you cannot access the files on the mounted volume. Use the /FOREIGN qualifier to mount volumes with formats of operating system that are not OpenVMS or with private formats.

Because foreign volumes are not file-structured, you must access them as follows:

• Disks---sequentially or by logical block number
• Tapes---sequentially

At times, the Backup utility (BACKUP) requires you to mount volumes with the /FOREIGN qualifier, when you restore an entire disk, for example. For details, refer to the OpenVMS System Management Utilities Reference Manual.

How to Perform This Task

When mounting volumes, follow these steps:

1. Physically mount all disks and put them on line.
2. Enter the MOUNT command (which invokes the Mount utility), using the following format:

   MOUNT device-name volume-label logical-name

   
   where:

   device-name	Specifies the physical device name or logical name of the device on which the volume is to be mounted.
   volume-label	Specifies the label on the volume.
   logical-name	Defines a logical name to be associated with the device.

Once invoked, the Mount utility performs the following actions:

1. Allocates the device
2. Checks to see that the device is correctly loaded
3. Reads and verifies the volume identification

Using Qualifiers with the MOUNT Command

Under special conditions, you must add qualifiers to the MOUNT command; for example:

• To mount a public volume, use the /SYSTEM qualifier with the DCL command MOUNT using the following format:

  MOUNT/SYSTEM device-name volume-label logical-name

• In an OpenVMS Cluster environment, also specify the /CLUSTER qualifier:

  MOUNT/SYSTEM/CLUSTER device-name volume-label logical-name

Table 8-13 and Table 8-14 show, respectively, the qualifiers you can use when you mount disks and tapes.

The following sections explain how to perform these tasks:

Task	Section
Use MOUNT command qualifiers when you mount disks	Section 8.5.1
Use MOUNT command qualifiers when you mount tapes	Section 8.5.2
Assist users with mounting	Section 8.5.3
Mount a volume with a protected subsystem	Section 8.5.4
Convert an existing volume from one ODS format to another	Section 8.5.5
Modify disk volume characteristics	Section 8.5.6

8.5.1 Using MOUNT Command Qualifiers When You Mount Disks

Table 8-13 lists MOUNT command qualifiers you can use to mount disks. The OpenVMS System Management Utilities Reference Manual has more information about each qualifier.

Table 8-13 MOUNT Command Qualifiers for Mounting Disks

Qualifier	Description
/ACCESSED= n	Requires OPER privilege; specifies the approximate number of directories that will be in use concurrently on the volume. (This qualifier is obsolete for ODS-2.) For example, on a large 500 megabyte (MB) disk you might select a value of 40, but on a small disk you might specify the following value: $ MOUNT/ACCESSED=2 DUA3:
/ASSIST	Directs the mount operation to allow operator or user intervention if the mount request fails. The /ASSIST qualifier is the default except during system startup. Encourage users to take advantage of this feature, which repeatedly alerts the operator of a mount request until the request is satisfied. To disable operator-assisted mounts, enter a command similar to the following: $ MOUNT/SYSTEM/NOASSIST DUA1: SALES_98
/BIND= volume-set-name	Creates a volume set of one or more disk volumes or adds one or more volumes to an existing volume set. For example: $ MOUNT/SYSTEM/BIND=CLIENTS DUA0:,DUA1: EUROPE,ASIA See Section 8.6.1.2 for details.
/CACHE= keyword	Controls whether caching limits established at system generation are disabled or overridden. For example: $ MOUNT/CACHE=(EXTENT=60,FILE_ID=60,QUOTA=20) - _$ DMA0: FILES WORK %MOUNT-I-MOUNTED, FILES mounted on _NODE$DMA0: This command mounts a device labeled FILES and assigns the logical name WORK. The /CACHE qualifier enables an extent cache of 60 entries, a file identification cache of 60 entries, and a quota cache of 20 entries.
/CLUSTER	Requires SYSNAM privilege; specifies that after a volume is successfully mounted on the local node, or if it is already mounted with the /SYSTEM qualifier on the local node, it is to be mounted on every other node in the existing OpenVMS Cluster environment (that is, the volume is to be mounted clusterwide). For example: $ MOUNT/SYSTEM/CLUSTER DUA1: SALES_95
/COMMENT= "string"	Specifies additional information to be included with the operator request when the mount operation requires operator assistance. For example: $ MOUNT/SYSTEM DYA1: SALES_95/COMMENT="Vol. in Rack 2."
/EXTENSION= n	Requires OPER privilege; specifies the number of blocks by which disk files are to be extended on the volume unless otherwise specified by an individual command or program request. The cluster size sets the initial disk block allocation; the /EXTENSION qualifier determines how the file grows. For example, for a small disk with a cluster size of 1 disk block, you might select an extension size of 2 disk blocks: $ MOUNT/EXTENSION=2 DUA3:
/FOREIGN	Indicates that the volume is not in the standard format used by the operating system. Use this qualifier if you want to mount a disk volume with a file structure other than Files--11 or ISO 9660; for example (using DISK as a logical name): $ MOUNT/FOREIGN DISK
/MEDIA_FORMAT=CDROM	Mounts a volume assuming the media to be ISO 9660 (or High Sierra) formatted.
/[NO]MOUNT_VERIFICATION	Enables or disables the mount verification feature on disks. By default, the mount verification feature is enabled. If a device goes off line or becomes write-locked, mount verification notifies the operator of the error condition, and then checks to see that the volume identification before and after the error condition are identical. To disable mount verification, enter a command like the following one: $ MOUNT/SYSTEM/NOMOUNT_VERIFICATION DUA1: ACCOUNTS_DUE
/OVERRIDE= keyword	Inhibits one or more protection checks that the MOUNT command performs.
/PROTECTION= keyword	Specifies the protection code to be assigned to the volume. Keywords are in the following list: Protection code: specifies the protection code according to the standard syntax rules for specifying user protection (that is, system/owner/group/world). XAR: enables enforcement of the extended record attribute (XAR) access controls (ISO 9660 only). DSI: enables XAR permissions owner and group for XARs containing DIGITAL System Identifiers (DSI). (ISO 9660 only.) See Section 8.4.1 for details.
/SHARE	Specifies that other users can access the volume. (However, you must use the /SYSTEM qualifier to mount public volumes.) Two users can access a private volume simultaneously if they both use MOUNT/SHARE. For example: $ MOUNT/SHARE DLA0: COST_ACCOUNT Using the MOUNT/SHARE command on disks already mounted with the /SYSTEM qualifier retains a lock on disk availability even if the disk is dismounted on a systemwide basis. This practice is not usually used for the system disk, but it can occur as a result of invoking a general-purpose command procedure that is sometimes used on system and nonsystem disks. If the DISMOUNT.EXE program is opened by a user and another user enters the MOUNT/SHARE command on the system disk, a subsequent dismount may produce a warning message that the disk cannot be dismounted. To prevent the message, install the DISMOUNT.EXE image.
/SUBSYSTEM	Enables the processing of subsystem ACEs. (The command MOUNT/SUBSYSTEM requires the SECURITY privilege.) By default, the disk from which you boot has /SUBSYSTEM enabled but other disks do not. The following command uses the MOUNT command with the /SUBSYSTEM qualifier to enable the processing of subsystem ACEs on the DUA0: device (DOC is the volume label; WORK8 is an optional logical name for the volume): $ MOUNT/SUBSYSTEM/SYSTEM DUA0: DOC WORK8
/SYSTEM	Requires SYSNAM privilege; makes the volume public, that is, available to all users of the system, as long as the UIC-based volume protection allows them access. The following command mounts the volume labeled WORK and makes it available systemwide: $ MOUNT/SYSTEM DUA1: WORK
/UCS_SEQUENCE= escape_sequence	Supplies the escape sequence to select the coded graphic character set, a requirement when mounting an ISO 9660 volume for one of its Supplementary Volume Descriptors (SVDs).
/UNDEFINED_FAT	Establishes default file attributes to be used for records on ISO 9660 media for which no record format has been specified.
/WINDOWS= n	Requires OPER privilege; specifies the number of mapping pointers to be allocated for file windows. The default number of windows is set with the INITIALIZE command. The following example specifies a modest number of pointers: $ MOUNT/WINDOWS=4 DUA3:

8.5.2 Using MOUNT Command Qualifiers When You Mount Tapes

Table 8-14 lists MOUNT command qualifiers you can use to mount a tape volume. For a complete list of MOUNT command qualifiers, refer to the OpenVMS System Management Utilities Reference Manual.

Unless otherwise noted, you must have VOLPRO privilege to use any of these qualifiers when the volume is a standard-labeled volume containing protection that disallows your process from accessing the volume.

Table 8-14 MOUNT Command Qualifiers for Mounting Tapes

Qualifier	Description
/BLOCKSIZE= n	Specifies the block size for the magnetic tape. The range of valid values for n varies, depending on the density of the volume, whether the data is for input or output, and whether the operation uses OpenVMS RMS. By default, the system writes 2048-byte blocks.
/CACHE=TAPE_DATA	Requires OPER privilege; enables the write cache for a tape device if the tape controller supports one. /NOCACHE is the default for mounting tape devices. You must specify TAPE_DATA to enable write caching. The write buffer stays enabled even after you dismount the tape.
/FOREIGN	Indicates that the volume is not in the standard format used by the operating system.
/HDR3	Controls whether special header labels are written on a tape volume. This is the default.
/[NO]MOUNT_VERIFICATION	Enables or disables the mount verification feature on magnetic tapes. By default, the mount verification feature is enabled. If a device goes off line or becomes write-locked, mount verification notifies the operator of the error condition, and then checks to see that the volume identification before and after the error condition are identical. To disable mount verification, enter a command similar to the following: $ MOUNT/SYSTEM/NOMOUNT_VERIFICATION MUA1: ACCOUNTS_DUE
/OVERRIDE= keyword	Inhibits one or more of the access checks that the MOUNT command performs. For example: $ MOUNT/OVERRIDE=IDENTIFICATION MFA0: This command overrides the volume identification field, thus mounting a magnetic tape on MFA0: without a label specification.
/OWNER_UIC= uic	Requests that the specified UIC be assigned ownership of the volume while it is mounted, overriding the ownership recorded on the volume. Or, if you are mounting a volume using the /FOREIGN qualifier, requests an owner UIC other than your current UIC.
/PROCESSOR= keyword	For magnetic tapes and Files--11 Structure Level 1 disks, requests that the MOUNT command associate an ancillary control process (ACP) to process the volume. You must have the operator user privilege OPER to use the /PROCESSOR qualifier. Keywords are in the following list: UNIQUE For magnetic tape and Files-11 ODS-1, ISO 9660, or High Sierra formatted media being mounted, creates a new process to execute a copy of the default ACP image for the specified device type or controller. For Files-11 Structure Level 2 or 5 disks, allocates a separate block cache. SAME: device For magnetic tape and Files-11 ODS-1, ISO 9660, or High Sierra formatted media being mounted, uses the same ACP process currently being used by the device specified. For Files-11 Structure Level 2 or 5 disks, takes the block cache allocation from the specified device. filespec Creates a new process to execute the ACP image specified by the file specification (for example, a modified or a user-written ACP). You cannot use wildcard characters or node and directory names in the file specification. To use this keyword, you must have CMKRNL and OPER privileges. The /PROCESSOR qualifier causes MOUNT to override the default manner in which ACPs are associated with devices. For example: $ MOUNT/PROCESSOR=SAME:MTA1: MFA0: This command directs MOUNT to mount a magnetic tape on MFA0: using the same ACP process currently associated with the MTA1: device.
/PROTECTION= code	Specifies the protection code to be assigned to the volume for the duration of the mount. See Section 8.4.2 for details.
/RECORDSIZE= n	Specifies the number of characters in each record of a magnetic tape volume. Use this qualifier when you mount a volume that has a file without a second header label (such as RT--11 volumes), or when you mount volumes with the /FOREIGN qualifier, to provide RMS with the size of fixed-length records or the maximum size of variable-length records.

Two other qualifiers that are important for mounting tape volumes are /INITIALIZE and /AUTOMATIC, which are explained in Section 8.8.2.2 and Section 8.8.2.3, respectively.

Example

$ MOUNT MU: TEST_FILES %MOUNT-I-OPRQST, Please mount volume TEST_FILES in device _MUA2: %MOUNT-I-MOUNTED, TEST_FILES mounted on _MUA2:

In this example, the MOUNT command requests an available RA90 device for the volume labeled TEST_FILES. After you physically mount the volume in the device named in the response from MOUNT, the system completes the operation. Note that the device is automatically allocated by MOUNT.

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.

8.5.3 Assisting Users in Mounting Volumes

Large sites often have operators assigned to assist users with mounting volumes. Section 2.4.6 explains how users can send requests to operators. Section 2.4.7 briefly explains how operators reply to those requests.

When a user requests you to mount a specific disk or tape on a device, the following type of message appears on the operator terminal:

%%%%%%%%%%% OPCOM, <dd-mmm-yyyy hh:mm:ss:cc> %%%%%%%%%%% request <request-id>, from user <user-name>

The following steps indicate the sequence of events:

1. A user requests that you mount the volume TEST_FILES on the device DUA2: by entering the following command:

   $ MOUNT DUA2: TEST_FILES/COMMENT="Shelf slot 6B"

2. OPCOM notifies you of the request by displaying a message similar to the following one at the operator terminal:

   %%%%%%%%%%% OPCOM, 28-MAY-1998 15:47:50.26 %%%%%%%%%%% request 5, from user MALCOLM Please mount volume TEST_FILES in device _DUA2: Shelf slot 6B

3. Once you receive the request, OPCOM delivers a confirmation to the user, in a format similar to the following:

   %MOUNT-I-OPRQST, Please mount volume TEST_FILES in device _DUA2: Shelf slot 6B

4. After you locate the volume and place it on the device, OPCOM notifies the user that the volume is on the device and that the task is complete:

   %MOUNT-I-MOUNTED,TEST_FILES mounted on _DUA2: %MOUNT-I-RQSTDON, operator request canceled -- mount completed successfully.

Instead of requesting a specific hardware device, such as DUA2:, for mounting a volume, users can make a generic MOUNT request. A generic MOUNT request specifies a type of device and lets you find an available device in that class. For example, to mount the volume CITIES on any tape drive whose name begins with MU, the user enters the following command:

$ MOUNT MU: CITIES/COMMENT="Slot 12c"

If the user has already allocated a drive whose name begins with MU, the Mount utility requests that you mount CITIES on that particular drive. If no device has been allocated, the Mount utility allocates the first available MU tape drive it finds and requests you to mount CITIES on that drive.

Sending Messages Back to Users

After you mount a disk or tape, follow these steps:

1. Use the operator communication manager (OPCOM) to communicate with system users. OPCOM is a system process that receives input from a process that wants to inform an operator of a particular status or condition; OPCOM passes the message to the operator, and tracks the message.
   To use OPCOM, you must use a terminal that has been designated as an operator terminal. See Section 2.4.5 for instructions.
2. Enter the REPLY command in one of the following forms:

   REPLY Command Qualifiers	Description
   /ABORT= identification-number "message-text"	Indicates that the user request is canceled. (The user's MOUNT command exits with an error status.)
   /PENDING= identification-number "message-text"	Indicates that the request has been put in a wait state until it can be completed. This command implies that the originating request was either a REQUEST/REPLY or a MOUNT command. The user cannot enter other commands until the operator fulfills or aborts the request.
   /TO= identification-number "message-text"	Indicates that the request is fulfilled. (Processing continues.)

   
   If a user enters a MOUNT/ASSIST command and the desired device is unavailable, you can substitute another device. Whenever you must substitute a device, load the requested volume on the alternate device and prepare the device for connection before you enter the REPLY command. Use the following format:

   REPLY/TO=identification-number "SUBSTITUTE device-name"

   
   You can abbreviate the word SUBSTITUTE to "S" and use uppercase or lowercase letters. After a space, use the remainder of the message-text space to name the substituted device.

Examples

1. $ REPLY/TO=24 "SUBSTITUTE DUA1:"

   
   This example shows how an operator redirects the mount operation to the DUA1: device.

2. $ MOUNT/ASSIST MKB500: MYDATA %MOUNT-I-OPRQST, Please mount volume MYDATA in device _MKB500: %MOUNT-I-OPREPLY, Substitute MKA100: 11:44:28.71, request 1 was completed by operator _FTA8:

   
   This is an example of a user's request and the substitution information the user receives. In this example, the MKA100: device has been substituted for the MKB500: device.

Refer to the OpenVMS DCL Dictionary for a complete list of REPLY qualifiers and their functions. See Section 8.8.2.4 for instructions for entering REPLY commands after you mount a volume set with automatic switching disabled.

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