Document revision date: 30 March 2001

## OpenVMS System Manager's Manual

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#### 9.4.1.2 Changing Protection After Disk Volumes Are Mounted

You can change protection by using the SET SECURITY/CLASS=VOLUME command with the /PROTECTION, /OWNER, or /ACL qualifier to change any aspect of the volume security profile.

Changing UIC-Based Protection

To change UIC-based protection after a volume is mounted, use the SET SECURITY/CLASS=VOLUME/PROTECTION command. For example:

    $ SET SECURITY/CLASS=VOLUME/PROTECTION=(S:RWCD,O:RWCD,G:RC,W:RC) DUA0:

The protection set in this example allows the system and owner all types of access. Group and world access types can only read files and run programs. Any category not specified in the protection code (S,O,G,W) is unchanged.

Changing ACL-Based Protection

To change ACL-based protection after a volume is mounted, use the SET SECURITY/CLASS=VOLUME/ACL command. To change the ACL, for example:

    $ SET SECURITY/CLASS=VOLUME/ACL=(IDENTIFIER=DOC,ACCESS=READ+WRITE+EXECUTE) -
    _$ $1$DSA7:

This example gives holders of the DOC identifier read, write, and execute access to the $1$DSA7: volume.

#### 9.4.1.3 Displaying UIC- and ACL-Based Protection

You can use the SHOW SECURITY/CLASS=VOLUME command to display protection. For example:

    $ SHOW SECURITY/CLASS=VOLUME $1$DSA27:

The following example shows the resulting display:

    $1$DSA27: object of class VOLUME
         Owner: [1,1]
         Protection: (System: RWCD, Owner: RWCD, Group: RWCD, World: RWCD)
         Access Control List:
              (IDENTIFIER=[ABC,SADAMS],ACCESS=READ+WRITE+CREATE+DELETE)

In the display are the name and profile of the VOLUME class object $1$DSA27. The profile includes the owner UIC, the protection code, and the access control list (ACL) of the protected object.

### 9.4.2 Protecting Tape Volumes

The system protects magnetic tapes only at the volume level. You establish protection when you initialize tape volumes; after that, the Mount utility (MOUNT) enforces the protection that you have established.

You can use two levels of protection for tape volumes:

Level of Protection | Description
--- | ---
Guidelines of the ISO standard | The ISO standard, which is the first level of protection, is encoded in the accessibility field of the first volume label written on the magnetic tape. With this protection scheme, you can protect tape volumes in environments where interchange exists between the OpenVMS system and the operating system that is not OpenVMS.
UIC-based protection scheme supported by system software | This second level of protection is encoded in the second volume label written on the magnetic tape. Only OpenVMS systems check this scheme; it is ignored in any interchange with operating systems that are not OpenVMS.

Standard-Labeled Tape Protection

The OpenVMS tape file system bases its accessibility protection on the ISO standards. This protection allows an installation routine to use a routine that interprets the contents of the volume- and header-label accessibility field. Refer to the $MTACCESS system service in the OpenVMS System Services Reference Manual for more information about installation routines.

Access Types with Default Protection

When you do not supply a protection code during initialization, all users receive read and write access, explained in Table 9-12.

Table 9-12 Access Types for Tape Volume Protection
Access Type | Gives you the right to...
--- | ---
Read | Examine, print, or copy files from the volume.
Write | Append or write files to the volume.

The security profile of a tape volume is stored in the ANSI VOL1 and VOL2 labels written on the tape. The VOL2 label contains system-specific information. To override the creation of VOL2 labels, specify the /INTERCHANGE qualifier with the INITIALIZE command or the INIT$_INTERCHANGE itemcode on the $INIT_VOL system service.

Foreign Volume Protection

The operating system also supports foreign tape volumes. (Foreign volumes either lack the standard volume label or have been mounted with the /FOREIGN qualifier.) When a tape volume is mounted with the /FOREIGN qualifier, users in the system and owner categories are always given full access (read, write, logical, and physical), regardless of what is specified in the protection code.

#### 9.4.2.1 Using the /PROTECTION Qualifier with Tape Volumes

If you use the /PROTECTION qualifier when you initialize tape volumes, the protection code is written to a system-specific volume label.

With the /PROTECTION qualifier, the system applies only read (R) and write (W) access restrictions. (Execute [E] and delete [D] access do not apply.) The system and the owner always receive both read (R) and write (W) access to magnetic tapes, regardless of the protection code you specify.

#### 9.4.2.2 Protecting Tape Volumes for Interchange Environments

You can protect tape volumes for interchange between OpenVMS and other operating systems.

The following list contains guidelines for protecting specific types of magnetic tapes:

- With tapes processed on any operating system that supports a version of the ANSI standard later than Version 3, the system processes accessibility information in the first volume label.
- To process magnetic tapes created on a Compaq operating system other than the OpenVMS operating system Version 4.0 or later, a user must have VOLPRO privilege and must explicitly override the check on the protection as follows:
  - If the tape was created with a specified accessibility, then a user must have the appropriate privilege and must explicitly override the check on accessibility.
  - If the tape volume was not created with such a protection scheme, then a user is granted read and write access to that tape volume.
- The tape file system allows you to specify values for the fields in which other Compaq operating systems currently write their protection information. Except under the conditions described in the last bulleted item, the OpenVMS operating system does not process these fields. Thus, you can use these fields to store the protection values for another operating system without affecting the system protection characteristics on that particular volume.

### 9.4.3 Auditing Volume Access

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.

## 9.5 Mounting 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 9_13 and Table 9-14 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 9.5.1
Use MOUNT command qualifiers when you mount tapes | Section 9.5.2
Assist users with mounting | Section 9.5.3
Mount a volume with a protected subsystem | Section 9.5.4
Convert an existing volume from one ODS format to another | Section 9.5.5
Modify disk volume characteristics | Section 9.5.6

### 9.5.1 Using MOUNT Command Qualifiers When You Mount Disks

Table 9-13 lists MOUNT command qualifiers you can use to mount disks. The OpenVMS System Management Utilities Reference Manual has more information about each qualifier.

Table 9-13 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 9.6.1.2 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 9.4.1 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:

### 9.5.2 Using MOUNT Command Qualifiers When You Mount Tapes

Table 9-14 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 9-14 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 9.4.2 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.

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