HP OpenVMS System Services Reference Manual

Contents

Index

$MOUNT

Mounts a tape, disk volume, or volume set and specifies options for the mount operation.

Format

SYS$MOUNT itmlst

C Prototype

int sys$mount (void *itmlst);

Argument

itmlst

OpenVMS usage: item_list_3

type: longword (unsigned)

access: read only

mechanism: by reference

Item list specifying options for the mount operation. The itmlst argument is the address of a list of item descriptors, each of which specifies an option and provides the information needed to perform the operation.
The item list must include at least one device item descriptor and is terminated by a longword value of 0.
The following diagram depicts the format of a single item descriptor:

The following table defines the item descriptor fields:

Descriptor Field Definition

Buffer length A word specifying the length (in bytes) of the buffer that supplies the information $MOUNT needs to process the specified item code. The required length of the buffer depends on the item code specified in the item code field of the item descriptor. If the value of the buffer length is too small, $MOUNT truncates the data.

Item code A word containing a user-supplied symbolic code that specifies an option for the MOUNT operation. The $MNTDEF macro defines these codes.

Buffer address A longword containing the address of the buffer that supplies information to $MOUNT.

Return length address This field is not used.

Descriptor Field	Definition
Buffer length	A word specifying the length (in bytes) of the buffer that supplies the information $MOUNT needs to process the specified item code. The required length of the buffer depends on the item code specified in the item code field of the item descriptor. If the value of the buffer length is too small, $MOUNT truncates the data.
Item code	A word containing a user-supplied symbolic code that specifies an option for the MOUNT operation. The $MNTDEF macro defines these codes.
Buffer address	A longword containing the address of the buffer that supplies information to $MOUNT.
Return length address	This field is not used.

Item Codes

[BMNT$_ACCESSED
Specifies the number of directories that will be in use, concurrently, on the volume. The buffer must contain a longword integer value in the range 0 to 255. This value overrides the number of directories specified when the volume was initialized. To specify MNT$_ACCESSED, the caller must have OPER privilege. The MNT$_ACCESSED item code applies only to disks.
MNT$_BLOCKSIZE
Specifies the default block size for tape volumes. The buffer must contain a longword integer value in the range 20 to 65,532 bytes for OpenVMS RMS operations or 10 to 65,534 bytes for operations that do not use RMS. The MNT$_BLOCKSIZE item code applies only to tapes.
If you do not specify MNT$_BLOCKSIZE, the default block size is 2048 bytes for Files-11 tape volumes and 512 bytes for foreign and unlabeled tapes.
You must specify MNT$_BLOCKSIZE when mounting (1) tapes that do not have ANSI HDR2 labels, (2) tapes to which data will be written from compatibility mode, and (3) tapes that are to contain records whose size is larger than the default value.
MNT$_COMMENT
Specifies text to be associated with an operator request. The buffer must contain a character string of no more than 78 characters. This text will be printed on the operator's console if an operator request is issued for the device being mounted.
MNT$_DATA
Specifies the Extended File Cache (XFC) to be enabled on the disk. To specify MNT$_DATA, you require OPER privilege. This is the default unless the NOQUOTA, NOFILEID, NOEXTENT, and WRITETHROUGH qualifiers are all specified with the MOUNT command.
MNT$_DENSITY
Specifies the density at which data is to be written to a foreign or unlabeled tape. The DENSITY item code suppled is dependent on the type of tape device. If a tape device is capable of using the MT3 density codes, the buffer for the MNT$DENSITY item code must contain a longword with one of the MT3 codes, as defined in SYS$LIBRARY:STARLET (MT3$K_TK50, MT3$K_3480, MT3$K_SDLT, MT3$K_AIT2, and so on). Refer to the MT3_SUPPORTED argument for $GETDVI.
If the device does not support MT3 densities, the buffer must contain a longword value that specifies one of the following legal densities: 800 bpi, 1600 bpi, or 6250 bpi.
The specified density will be used only if (1) the tape is foreign or unlabeled and (2) the first operation is a write.
MNT$_DEVNAM
Specifies the name of the device to be mounted. The buffer must contain a character string of from 1 to 64 characters, which is the device name. The device name can be a physical device name or a logical name; if it is a logical name, it must translate to a physical device name.
The MNT$_DEVNAM item code must appear at least once in an item list, and it can appear more than once. It appears more than once when a volume set is being mounted, because, in this case, one device is being mounted for each volume in the volume set.
MNT$_EXTENSION
Specifies the number of blocks by which files will be extended. The buffer must contain a longword value in the range 0 to 65,535. The MNT$_EXTENSION item code applies only to disks.
MNT$_EXTENT
Specifies the size of the extent cache in units of extent pointers. The buffer must contain a longword value, which specifies this size. To specify MNT$_EXTENT, you need OPER privilege. The value 0 (the default) disables caching. The MNT$_EXTENT item code applies only to disks.
MNT$_FILEID
Specifies the size of the file-ID cache in units of file numbers. The buffer must contain a longword value, which specifies this size. To specify MNT$_FILEID, you need OPER privilege. The value 1 disables caching. The MNT$_FILEID item code applies only to disks.
MNT$_FLAGS
Specifies a 2-longword bit vector wherein each bit specifies an option for the mount operation. The buffer must contain a quadword, which is the bit vector.
The $MNTDEF macro defines symbolic names for each option (bit) in the bit vector. You construct the bit vector by specifying the symbolic names for the desired options in a logical OR operation. In the first longword you logically OR the MNT$M_ mask bits, and in the second longword you logically OR the MNT2$M_ mask bits. The following table describes the symbolic names for each option. The MNT2$M_ options are at the end of the table.

Option Description

MNT$M_CLUSTER The volume is to be mounted for clusterwide access; that is, every OpenVMS Cluster node can access the volume. $MOUNT mounts the volume first on the caller's node and then on every other node in the existing cluster.
Only system or group volumes can be mounted clusterwide. If you do not specify MNT$M_GROUP or MNT$M_SYSTEM, $MOUNT mounts the volume as a system volume, provided the caller has SYSNAM privilege. To mount a group volume clusterwide, the caller must have GRPNAM privilege. To mount a system volume clusterwide, the caller must have SYSNAM privilege.
MNT$M_CLUSTER has no effect if the system is not a member of a cluster. MNT$M_CLUSTER applies only to disks.

MNT$M_FOREIGN The volume is to be mounted as a foreign volume; a foreign volume is not Files-11 structured. If you specify MNT$M_FOREIGN, the following item codes can each appear in the item list only once: the caller must either own the volume or have VOLPRO privilege.

MNT$M_GROUP The logical name for the volume to be mounted is entered in the group logical name table, and the volume is made accessible to other users with the same UIC group number as that of the calling process. To specify MNT$M_GROUP, the caller must have GRPNAM privilege. MNT$M_GROUP applies only to disks.

MNT$M_INCLUDE Automatically reconstructs a shadow set to the state it was in before the shadow set was dissolved (due to dismounting or system failure). Use this option to mount a shadow set or a volume set of shadow sets. You must specify the exact name of the original virtual unit and the device name of at least one of the shadow set members. The shadowing software reads the shadow set membership information from the named device to determine the membership of the original shadow set. You can include the MNT$M_INCLUDE option in executable images to have a shadow set reconstructed. Using MNT$M_INCLUDE prevents your having to manually reinstate shadow sets after they have been dismounted.
If you do not select this option, $MOUNT does not automatically reconstruct the former shadow set.

MNT$M_INIT_CONT Additional volumes in the volume set are to be initialized without operator intervention. $MOUNT initializes new volumes with the protections specified for the first magnetic tape of the volume set and creates unique volume label names for up to 99 volumes in a volume set.

If MNT$M_INIT_CONT is specified, you must allocate multiple magnetic tape drives to the volume set. If $MOUNT switches to a drive that has no magnetic tape loaded or has the wrong magnetic tape loaded or if $MOUNT tries to read a magnetic tape that is not loaded, it notifies the operator to load the correct magnetic tape. $MOUNT will dismount and unload volumes as soon as they have been read or written. The operator can load the next volume in the volume set before the current reel of the volume set reaches the end of the magnetic tape.

If writing to the volume set, $MOUNT automatically (1) switches to the next magnetic tape drive, (2) initializes that magnetic tape with the same volume name and protection as specified in the volume labels of the first volume in the set, and (3) notifies the operator that the switch has occurred. If reading the volume set, $MOUNT generates the label for the next volume in the volume set and reads that volume.

The label name that $MOUNT generates for each additional volume in the volume set consists of six characters: the first four characters are the same as the first four characters of the label name of the previous volume; the fifth and sixth characters represent the number of the volume in the volume set.
MNT$M_INIT_CONT applies only to magnetic tapes.

MNT$M_MESSAGE Messages will be sent to the caller's SYS$OUTPUT device.

MNT$M_MINICOPY_OPTIONAL $MOUNT fails if minicopy has not been enabled on the disk.

MNT$M_MINICOPY_REQUIRED $MOUNT continues even if minicopy has not been enabled on the disk.

MNT$M_MULTI_VOL Specifies, for foreign or unlabeled magnetic tapes, that subsequent volumes can be processed by overriding MOUNT's access checks. You can use this option when a utility that supports multivolume magnetic tape sets needs to process subsequent volumes, and these volumes do not contain labels that MOUNT can interpret. You need VOLPRO privilege to specify the MNT$M_MULTI_VOL option. MNT$M_MULTI_VOL can only be used with the MNT$M_FOREIGN option.
HP recommends the use of this qualifier only when it is not possible to alter the utility to explicitly perform MOUNT and DISMOUNT operations on each reel in the set.

MNT$M_NOASSIST $MOUNT does not request operator assistance if errors are encountered during the mount operation. If not specified, $MOUNT requests operator assistance to recover from some error conditions.

MNT$M_NOAUTO Automatic volume labeling (AVL) and automatic volume recognition (AVR) are to be disabled. If MNT$M_NOAUTO is specified, the operator must enter commands from the console to process each additional volume in a volume set. When a volume is finished processing, the operator specifies the drive on which the next volume is loaded and the label name of the next volume. You might want to use MNT$M_NOAUTO to disable AVL and AVR when not reading a volume set sequentially.
You can enable AVL and AVR by specifying MNT$M_INIT_CONT. MNT$M_NOAUTO applies only to magnetic tapes.

MNT$M_NOCACHE All caching associated with the volume is turned off. Specifying MNT$M_NOCACHE is equivalent to (1) specifying MNT$M_WRITETHRU, (2) specifying a value of 1 for the item descriptor MNT$_FILEID, and (3) specifying a value of 0 for the item descriptors MNT$M_EXTENT and MNT$M_QUOTA.

MNT$M_NOCOPY Disables full copy operations on all physical devices being mounted or added to a shadow set. This option provides you with the opportunity to confirm the states of all of the devices or members of a shadow set before proceeding with any full copy operation. This prevents any accidental loss of data that could occur if an unintended device is added to the shadow set.
If you do not select this option, $MOUNT automatically overwrites the data on shadow set members that are not current. When you select this option, a $MOUNT operation fails if any of the specified potential shadow set members require full copy operations.

MNT$M_NODISKQ Disk quotas are not to be enforced for the volume to be mounted. If not specified, disk quotas are enforced. To specify MNT$M_NODISKQ, the caller must either own the volume or have VOLPRO privilege. MNT$M_NODISKQ applies only to disks.

MNT$M_NOHDR3 ANSI HDR3 and HDR4 labels are not to be written to magnetic tapes as they are mounted. If not specified, ANSI HDR3 and HDR4 labels are written to all tapes.
Use MNT$M_NOHDR3 when writing to volumes that will be read by a system, such as the RT-11 system, which does not process HDR3 and HDR4 labels correctly. MNT$M_NOHDR3 applies only to tapes.

MNT$M_NOLABEL The volume is to be mounted as a foreign volume; a foreign volume is not Files-11 structured. If you specify MNT$M_NOLABEL, the following item codes can each appear in the item list only once: MNT$_DEVNAM, MNT$_VOLNAM, and MNT$_LOGNAM. To specify MNT$M_NOLABEL, the caller must either own the volume or have VOLPRO privilege.

MNT$M_NOMNTVER The volume is not marked as a candidate for automatic mount verification. If not specified, the volume is marked as a candidate for mount verification.

MNT$M_NOREBUILD The volume to be mounted should be returned to active use immediately, without performing a rebuild operation. This flag defers the disk rebuild operation, so that the volume to be mounted is returned to active use immediately. A rebuild operation can consume a considerable amount of time, depending on the number of files on the volume and on the number of different file owners (if quotas are in use). The volume can be rebuilt later with the DCL command SET VOLUME/REBUILD to recover the free space; for more information, see the HP OpenVMS DCL Dictionary.
If a disk volume is improperly dismounted, for example, during a system failure, it must be rebuilt to recover any caching limits that were enabled on the volume at the time of the dismount. By default, $MOUNT attempts to rebuild.
When mounting a volume set, you must mount all members of the set to reclaim all available free space.
MNT$M_NOREBUILD applies only to disks.

MNT$M_NOUNLOAD The volume to be mounted is not to be unloaded when it is dismounted. Specifying MNT$M_NOUNLOAD causes the volume to remain loaded when it is dismounted unless the dismount explicitly requests that the volume be unloaded.

MNT$M_NOWRITE The volume to be mounted is software write locked. If not specified, the volume is assumed to have read and write access.

MNT$M_OVR_ACCESS If the installation allows, this option overrides any character in the accessibility field of the volume. The necessity of this option is defined by the installation. That is, each installation has the option of specifying a routine that the magnetic tape file system will use to process this field. By default, the operating system provides a routine that checks this field in the following manner:

If the magnetic tape was created on a version of the operating system that conforms to Version 3 of ANSI, then you must use this option to override any character other than an ASCII space.
If a protection is specified and that magnetic tape conforms to an ANSI standard that is higher than Version 3, then you must use this option to override any character other than an ASCII 1.

To specify MNT$M_OVR_ACCESS, the caller must either own the volume or have VOLPRO privilege. MNT$M_OVR_ACCESS applies only to tapes.

MNT$M_OVR_EXP A tape that has not yet reached its expiration date can be overwritten. To specify MNT$M_OVR_EXP, the caller must own the volume or have VOLPRO privilege.

MNT$M_OVR_IDENT You can mount the volume without specifying the volume name (by using the MNT$_VOLNAM item code). If specified, the following options must not be specified: MNT$M_CLUSTER, MNT$M_GROUP, MNT$M_SHARE, and MNT$M_SYSTEM.

MNT$M_OVR_LOCK The software write lock that occurs when a volume has a corrupted storage bit mask can be overridden.

MNT$M_OVR_SETID Checks on the volume set identification are not to be performed when subsequent reels in the volume set are mounted. MNT$M_OVR_SETID applies only to tapes.

MNT$M_OVR_SHAMEM Allows you to mount former shadow set members outside of the shadow set. If you do not specify this option, $MOUNT automatically mounts the volume write-locked to prevent accidental deletion of data. To specify this option, you must either own the volume or have VOLPRO privilege.
When you use this option, the shadow set generation number is erased from the volume. If you then remount the volume in the former shadow set, $MOUNT considers it an unrelated volume and marks it for a full copy operation.

MNT$M_OVR_VOLO The volume label's owner identifier field is not to be processed. $MOUNT reads volume owner and protection information from the volume owner field of the volume labels.
The operating system requires that you specify MNT$M_OVR_VOLO to process magnetic tapes when all of the following conditions exist: (1) the volume was created on an operating system other than OpenVMS; (2) the volume was initialized with a protection specified; and (3) the volume conforms to the Version 3 ANSI label standard.
To specify MNT$M_OVR_VOLO, the caller must either have VOLPRO privilege or own the volume. MNT$M_OVR_VOLO applies only to tapes.

MNT$M_READCHECK Read checks are to be performed following all read operations.

MNT$M_REQUIRE_MEMBERS Controls whether every physical device specified with the /SHADOW qualifier must be accessible when the MOUNT command is issued in order for the $MOUNT system service to take effect.

MNT$M_SHARE Volume is to be mounted shared and is therefore accessible to other users. MNT$M_SHARE applies only to disks.
If the volume was previously mounted shared by another user and MNT$M_SHARE is specified in the current call, all other options specified in the current call are ignored.
If the caller allocated the device and specified MNT$M_SHARE in the call to $MOUNT, $MOUNT will deallocate the device so that other users can access the volume.

MNT$M_SYSTEM The logical name for the volume to be mounted is entered in the system logical name table, and the volume is made accessible to all other users, provided that UIC-based protection allows access to the volume. To specify MNT$M_SYSTEM, the caller must have SYSNAM privilege. MNT$M_SYSTEM applies only to disks.

MNT$M_TAPE_DATA_WRITE Enables the tape controller's write cache for this device. Enabling the write cache improves data throughput for write operations. By default, the tape controller's write cache is disabled for the device.
This option applies only to tape systems that support a write cache.

MNT$M_VERIFY_LABEL Requires that any member to be added to the shadow set have a volume label of SCRATCH_DISK. This helps ensure that the wrong disk is not added to a shadow set. If you plan to use VERIFY_LABEL, you must first assign the disk to a label. You can do this either by initializing the disk to be added to the set with the label SCRATCH_DISK, or by specifying the label for the disk with the SET VOLUME/LABEL command.

MNT$M_WRITECHECK Write checks are to be performed after all write operations.

MNT$M_WRITETHRU Disables the deferred write feature for file headers. By default this feature is enabled, which improves the performance of the applications, such as PATHWORKS, that use it. The deferred write feature is not available on Files-11 ODS-1 volumes.

MNT2$M_CDROM Mounts a volume assuming the media to be ISO 9660 (or High Sierra) formatted.

MNT2$M_COMPACTION Enables data compaction for those magnetic tapes that support data compaction (TA90, TA91, and others).

MNT2$M_DISKQ Controls whether quotas are to be enforced on the specified disk volume.

MNT2$_DSI Enables XAR permissions Owner and Group for XARs containing DIGITAL System Identifiers (DSI). For more information, see the OpenVMS Record Management Services Reference Manual.

MNT2$_INCLUDE Automatically reconstructs a former shadow set to the way it was before the shadow set was dissolved. Applicable only if you have the volume shadowing option. For more information, see HP Volume Shadowing for OpenVMS.

MNT2$M_NOCOMPACTION Forces the density to no compaction for those magnetic tapes that support data compaction (TA90, TA91, and others).

MNT2$_OVR_LIMITED_SEARCH For disk type devices that do not provide for bad-block revectoring, it is possible that the Files-11 homeblock has been placed numerous I/Os from the start of the volume. To decrease the failover time when accessing media which does not contain a valid Files-11 homeblock, a limited-search algorithm was implemented. This switch overrides the limited-search algorithm so that the entire volume will be searched for a valid Files-11 homeblock.

MNT2$M_OVR_NOFE This bit mask is set to override those SCSI devices that do not support forced error functionality. By overriding those SCSI devices not supporting forced error capabilities, MNT2$M_OVR_NOFE enables those devices to be mounted; otherwise, the shadowing code would report to $MOUNT that the device does not support forced error, and the device would not be mounted.

MNT2$_OVR_SECURITY Enables you to continue mounting a volume if an error is returned because the volume has an invalid SECURITY.SYS file. You must have the VOLPRO privilege or own the volume to use this keyword.

MNT2$M_SUBSYSTEM Enables the processing of protected subsystem identifiers on the volume. By default, subsystem identifiers are ignored on all but the system disk. Requires SECURITY privilege.

MNT2$M_XAR Enables enforcement of the extended record attribute (XAR) access controls. For more information about XAR, see the HP OpenVMS System Manager's Manual.

MNT$_LIMIT
Specifies the maximum amount of free space in the extent cache. The buffer must contain a longword value, which specifies the amount of free space in units of tenths of a percent of the disk's total free space. The MNT$_LIMIT item code applies only to disks.
MNT$_LOGNAM
Specifies a logical name for the volume; this logical name is equated to the device name specified by the first MNT$_DEVNAM item code. The buffer must contain a character string from 1 to 64 characters, which is the logical name.
Unless you specify MNT$M_GROUP or MNT$M_SYSTEM, the logical name is entered in the process logical name table.
MNT$_NODATA
Specifies whether the XFC is to be disabled on the disk. This value is the default, when you specify NOQUOTA, NOFILEID, NOEXTENT, or WRITETHROUGH qualifier with the MOUNT command.
MNT$_OWNER
Specifies the UIC to be assigned ownership of the volume. The buffer must contain a longword octal value, which is the UIC. If the volume is Files-11 structured, the specified value overrides the ownership recorded on the volume. You need either VOLPRO privilege or ownership of the volume to assign a UIC to a Files-11 structured volume.
MNT$_PROCESSOR
For magnetic tapes and Files-11 On-Disk Structure Level 1 disks, MNT$_PROCESSOR specifies the name of the ancillary control process (ACP) that is to process the volume. The specified ACP overrides the default ACP associated with the device.
For Files-11 On-Disk Structure Level 2 disks, MNT$_PROCESSOR controls block cache allocation.
To specify MNT$_PROCESSOR, the caller must have OPER privilege.
The buffer must contain a character string specifying either the string UNIQUE, a device name, or a file specification. Following is a description of the action taken for each of these cases:

String Description

UNIQUE For magnetic tapes and Files-11 Structure Level 1 disks, UNIQUE specifies that $MOUNT create a new process to execute a copy of the default ACP image associated with the device specified by the MNT$_DEVNAM item code.
For Files-11 Structure Level 2 disks, UNIQUE allocates a separate block cache.

ddcu For magnetic tapes and Files-11 Structure Level 1 disks, ddcu specifies that $MOUNT use the ACP process currently being used by the device ddcu. The device specified must be in the format ddcu, for example, DRA3.
For Files-11 Structure Level 1 disks, ddcu specifies that $MOUNT take the block allocation from the specified device.

filespec Specifies that $MOUNT create a new process to execute the ACP image with the file specification filespec. Wildcard characters are not allowed in the file specification. The file must be in the disk and directory specified by the logical name SYS$SYSTEM. This operation requires CMKRNL privilege.

MNT$_QUOTA
Specifies the size of the quota record cache in units of quota records. The buffer must contain a longword value, which is this size. To specify MNT$_QUOTA, you need OPER privilege. The value 0 disables caching. The MNT$_QUOTA item code applies only to disks.
MNT$_RECORDSIZ
Specifies the number of characters in each record and is used with MNT$_BLOCKSIZE to specify the data formats for foreign volumes. The buffer must contain a longword value less than or equal to the block size. The MNT$_RECORDSIZ item code applies only to tapes.

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OpenVMS usage:	item_list_3
type:	longword (unsigned)
access:	read only
mechanism:	by reference

Option	Description
MNT$M_CLUSTER	The volume is to be mounted for clusterwide access; that is, every OpenVMS Cluster node can access the volume. $MOUNT mounts the volume first on the caller's node and then on every other node in the existing cluster. Only system or group volumes can be mounted clusterwide. If you do not specify MNT$M_GROUP or MNT$M_SYSTEM, $MOUNT mounts the volume as a system volume, provided the caller has SYSNAM privilege. To mount a group volume clusterwide, the caller must have GRPNAM privilege. To mount a system volume clusterwide, the caller must have SYSNAM privilege. MNT$M_CLUSTER has no effect if the system is not a member of a cluster. MNT$M_CLUSTER applies only to disks.
MNT$M_FOREIGN	The volume is to be mounted as a foreign volume; a foreign volume is not Files-11 structured. If you specify MNT$M_FOREIGN, the following item codes can each appear in the item list only once: the caller must either own the volume or have VOLPRO privilege.
MNT$M_GROUP	The logical name for the volume to be mounted is entered in the group logical name table, and the volume is made accessible to other users with the same UIC group number as that of the calling process. To specify MNT$M_GROUP, the caller must have GRPNAM privilege. MNT$M_GROUP applies only to disks.
MNT$M_INCLUDE	Automatically reconstructs a shadow set to the state it was in before the shadow set was dissolved (due to dismounting or system failure). Use this option to mount a shadow set or a volume set of shadow sets. You must specify the exact name of the original virtual unit and the device name of at least one of the shadow set members. The shadowing software reads the shadow set membership information from the named device to determine the membership of the original shadow set. You can include the MNT$M_INCLUDE option in executable images to have a shadow set reconstructed. Using MNT$M_INCLUDE prevents your having to manually reinstate shadow sets after they have been dismounted. If you do not select this option, $MOUNT does not automatically reconstruct the former shadow set.
MNT$M_INIT_CONT	Additional volumes in the volume set are to be initialized without operator intervention. $MOUNT initializes new volumes with the protections specified for the first magnetic tape of the volume set and creates unique volume label names for up to 99 volumes in a volume set.
	If MNT$M_INIT_CONT is specified, you must allocate multiple magnetic tape drives to the volume set. If $MOUNT switches to a drive that has no magnetic tape loaded or has the wrong magnetic tape loaded or if $MOUNT tries to read a magnetic tape that is not loaded, it notifies the operator to load the correct magnetic tape. $MOUNT will dismount and unload volumes as soon as they have been read or written. The operator can load the next volume in the volume set before the current reel of the volume set reaches the end of the magnetic tape.
	If writing to the volume set, $MOUNT automatically (1) switches to the next magnetic tape drive, (2) initializes that magnetic tape with the same volume name and protection as specified in the volume labels of the first volume in the set, and (3) notifies the operator that the switch has occurred. If reading the volume set, $MOUNT generates the label for the next volume in the volume set and reads that volume.
	The label name that $MOUNT generates for each additional volume in the volume set consists of six characters: the first four characters are the same as the first four characters of the label name of the previous volume; the fifth and sixth characters represent the number of the volume in the volume set. MNT$M_INIT_CONT applies only to magnetic tapes.
MNT$M_MESSAGE	Messages will be sent to the caller's SYS$OUTPUT device.
MNT$M_MINICOPY_OPTIONAL	$MOUNT fails if minicopy has not been enabled on the disk.
MNT$M_MINICOPY_REQUIRED	$MOUNT continues even if minicopy has not been enabled on the disk.
MNT$M_MULTI_VOL	Specifies, for foreign or unlabeled magnetic tapes, that subsequent volumes can be processed by overriding MOUNT's access checks. You can use this option when a utility that supports multivolume magnetic tape sets needs to process subsequent volumes, and these volumes do not contain labels that MOUNT can interpret. You need VOLPRO privilege to specify the MNT$M_MULTI_VOL option. MNT$M_MULTI_VOL can only be used with the MNT$M_FOREIGN option. HP recommends the use of this qualifier only when it is not possible to alter the utility to explicitly perform MOUNT and DISMOUNT operations on each reel in the set.
MNT$M_NOASSIST	$MOUNT does not request operator assistance if errors are encountered during the mount operation. If not specified, $MOUNT requests operator assistance to recover from some error conditions.
MNT$M_NOAUTO	Automatic volume labeling (AVL) and automatic volume recognition (AVR) are to be disabled. If MNT$M_NOAUTO is specified, the operator must enter commands from the console to process each additional volume in a volume set. When a volume is finished processing, the operator specifies the drive on which the next volume is loaded and the label name of the next volume. You might want to use MNT$M_NOAUTO to disable AVL and AVR when not reading a volume set sequentially. You can enable AVL and AVR by specifying MNT$M_INIT_CONT. MNT$M_NOAUTO applies only to magnetic tapes.
MNT$M_NOCACHE	All caching associated with the volume is turned off. Specifying MNT$M_NOCACHE is equivalent to (1) specifying MNT$M_WRITETHRU, (2) specifying a value of 1 for the item descriptor MNT$_FILEID, and (3) specifying a value of 0 for the item descriptors MNT$M_EXTENT and MNT$M_QUOTA.
MNT$M_NOCOPY	Disables full copy operations on all physical devices being mounted or added to a shadow set. This option provides you with the opportunity to confirm the states of all of the devices or members of a shadow set before proceeding with any full copy operation. This prevents any accidental loss of data that could occur if an unintended device is added to the shadow set. If you do not select this option, $MOUNT automatically overwrites the data on shadow set members that are not current. When you select this option, a $MOUNT operation fails if any of the specified potential shadow set members require full copy operations.
MNT$M_NODISKQ	Disk quotas are not to be enforced for the volume to be mounted. If not specified, disk quotas are enforced. To specify MNT$M_NODISKQ, the caller must either own the volume or have VOLPRO privilege. MNT$M_NODISKQ applies only to disks.
MNT$M_NOHDR3	ANSI HDR3 and HDR4 labels are not to be written to magnetic tapes as they are mounted. If not specified, ANSI HDR3 and HDR4 labels are written to all tapes. Use MNT$M_NOHDR3 when writing to volumes that will be read by a system, such as the RT-11 system, which does not process HDR3 and HDR4 labels correctly. MNT$M_NOHDR3 applies only to tapes.
MNT$M_NOLABEL	The volume is to be mounted as a foreign volume; a foreign volume is not Files-11 structured. If you specify MNT$M_NOLABEL, the following item codes can each appear in the item list only once: MNT$_DEVNAM, MNT$_VOLNAM, and MNT$_LOGNAM. To specify MNT$M_NOLABEL, the caller must either own the volume or have VOLPRO privilege.
MNT$M_NOMNTVER	The volume is not marked as a candidate for automatic mount verification. If not specified, the volume is marked as a candidate for mount verification.
MNT$M_NOREBUILD	The volume to be mounted should be returned to active use immediately, without performing a rebuild operation. This flag defers the disk rebuild operation, so that the volume to be mounted is returned to active use immediately. A rebuild operation can consume a considerable amount of time, depending on the number of files on the volume and on the number of different file owners (if quotas are in use). The volume can be rebuilt later with the DCL command SET VOLUME/REBUILD to recover the free space; for more information, see the HP OpenVMS DCL Dictionary. If a disk volume is improperly dismounted, for example, during a system failure, it must be rebuilt to recover any caching limits that were enabled on the volume at the time of the dismount. By default, $MOUNT attempts to rebuild. When mounting a volume set, you must mount all members of the set to reclaim all available free space. MNT$M_NOREBUILD applies only to disks.
MNT$M_NOUNLOAD	The volume to be mounted is not to be unloaded when it is dismounted. Specifying MNT$M_NOUNLOAD causes the volume to remain loaded when it is dismounted unless the dismount explicitly requests that the volume be unloaded.
MNT$M_NOWRITE	The volume to be mounted is software write locked. If not specified, the volume is assumed to have read and write access.
MNT$M_OVR_ACCESS	If the installation allows, this option overrides any character in the accessibility field of the volume. The necessity of this option is defined by the installation. That is, each installation has the option of specifying a routine that the magnetic tape file system will use to process this field. By default, the operating system provides a routine that checks this field in the following manner: If the magnetic tape was created on a version of the operating system that conforms to Version 3 of ANSI, then you must use this option to override any character other than an ASCII space. If a protection is specified and that magnetic tape conforms to an ANSI standard that is higher than Version 3, then you must use this option to override any character other than an ASCII 1. To specify MNT$M_OVR_ACCESS, the caller must either own the volume or have VOLPRO privilege. MNT$M_OVR_ACCESS applies only to tapes.
MNT$M_OVR_EXP	A tape that has not yet reached its expiration date can be overwritten. To specify MNT$M_OVR_EXP, the caller must own the volume or have VOLPRO privilege.
MNT$M_OVR_IDENT	You can mount the volume without specifying the volume name (by using the MNT$_VOLNAM item code). If specified, the following options must not be specified: MNT$M_CLUSTER, MNT$M_GROUP, MNT$M_SHARE, and MNT$M_SYSTEM.
MNT$M_OVR_LOCK	The software write lock that occurs when a volume has a corrupted storage bit mask can be overridden.
MNT$M_OVR_SETID	Checks on the volume set identification are not to be performed when subsequent reels in the volume set are mounted. MNT$M_OVR_SETID applies only to tapes.
MNT$M_OVR_SHAMEM	Allows you to mount former shadow set members outside of the shadow set. If you do not specify this option, $MOUNT automatically mounts the volume write-locked to prevent accidental deletion of data. To specify this option, you must either own the volume or have VOLPRO privilege. When you use this option, the shadow set generation number is erased from the volume. If you then remount the volume in the former shadow set, $MOUNT considers it an unrelated volume and marks it for a full copy operation.
MNT$M_OVR_VOLO	The volume label's owner identifier field is not to be processed. $MOUNT reads volume owner and protection information from the volume owner field of the volume labels. The operating system requires that you specify MNT$M_OVR_VOLO to process magnetic tapes when all of the following conditions exist: (1) the volume was created on an operating system other than OpenVMS; (2) the volume was initialized with a protection specified; and (3) the volume conforms to the Version 3 ANSI label standard. To specify MNT$M_OVR_VOLO, the caller must either have VOLPRO privilege or own the volume. MNT$M_OVR_VOLO applies only to tapes.
MNT$M_READCHECK	Read checks are to be performed following all read operations.
MNT$M_REQUIRE_MEMBERS	Controls whether every physical device specified with the /SHADOW qualifier must be accessible when the MOUNT command is issued in order for the $MOUNT system service to take effect.
MNT$M_SHARE	Volume is to be mounted shared and is therefore accessible to other users. MNT$M_SHARE applies only to disks. If the volume was previously mounted shared by another user and MNT$M_SHARE is specified in the current call, all other options specified in the current call are ignored. If the caller allocated the device and specified MNT$M_SHARE in the call to $MOUNT, $MOUNT will deallocate the device so that other users can access the volume.
MNT$M_SYSTEM	The logical name for the volume to be mounted is entered in the system logical name table, and the volume is made accessible to all other users, provided that UIC-based protection allows access to the volume. To specify MNT$M_SYSTEM, the caller must have SYSNAM privilege. MNT$M_SYSTEM applies only to disks.
MNT$M_TAPE_DATA_WRITE	Enables the tape controller's write cache for this device. Enabling the write cache improves data throughput for write operations. By default, the tape controller's write cache is disabled for the device. This option applies only to tape systems that support a write cache.
MNT$M_VERIFY_LABEL	Requires that any member to be added to the shadow set have a volume label of SCRATCH_DISK. This helps ensure that the wrong disk is not added to a shadow set. If you plan to use VERIFY_LABEL, you must first assign the disk to a label. You can do this either by initializing the disk to be added to the set with the label SCRATCH_DISK, or by specifying the label for the disk with the SET VOLUME/LABEL command.
MNT$M_WRITECHECK	Write checks are to be performed after all write operations.
MNT$M_WRITETHRU	Disables the deferred write feature for file headers. By default this feature is enabled, which improves the performance of the applications, such as PATHWORKS, that use it. The deferred write feature is not available on Files-11 ODS-1 volumes.
MNT2$M_CDROM	Mounts a volume assuming the media to be ISO 9660 (or High Sierra) formatted.
MNT2$M_COMPACTION	Enables data compaction for those magnetic tapes that support data compaction (TA90, TA91, and others).
MNT2$M_DISKQ	Controls whether quotas are to be enforced on the specified disk volume.
MNT2$_DSI	Enables XAR permissions Owner and Group for XARs containing DIGITAL System Identifiers (DSI). For more information, see the OpenVMS Record Management Services Reference Manual.
MNT2$_INCLUDE	Automatically reconstructs a former shadow set to the way it was before the shadow set was dissolved. Applicable only if you have the volume shadowing option. For more information, see HP Volume Shadowing for OpenVMS.
MNT2$M_NOCOMPACTION	Forces the density to no compaction for those magnetic tapes that support data compaction (TA90, TA91, and others).
MNT2$_OVR_LIMITED_SEARCH	For disk type devices that do not provide for bad-block revectoring, it is possible that the Files-11 homeblock has been placed numerous I/Os from the start of the volume. To decrease the failover time when accessing media which does not contain a valid Files-11 homeblock, a limited-search algorithm was implemented. This switch overrides the limited-search algorithm so that the entire volume will be searched for a valid Files-11 homeblock.
MNT2$M_OVR_NOFE	This bit mask is set to override those SCSI devices that do not support forced error functionality. By overriding those SCSI devices not supporting forced error capabilities, MNT2$M_OVR_NOFE enables those devices to be mounted; otherwise, the shadowing code would report to $MOUNT that the device does not support forced error, and the device would not be mounted.
MNT2$_OVR_SECURITY	Enables you to continue mounting a volume if an error is returned because the volume has an invalid SECURITY.SYS file. You must have the VOLPRO privilege or own the volume to use this keyword.
MNT2$M_SUBSYSTEM	Enables the processing of protected subsystem identifiers on the volume. By default, subsystem identifiers are ignored on all but the system disk. Requires SECURITY privilege.
MNT2$M_XAR	Enables enforcement of the extended record attribute (XAR) access controls. For more information about XAR, see the HP OpenVMS System Manager's Manual.

String	Description
UNIQUE	For magnetic tapes and Files-11 Structure Level 1 disks, UNIQUE specifies that $MOUNT create a new process to execute a copy of the default ACP image associated with the device specified by the MNT$_DEVNAM item code. For Files-11 Structure Level 2 disks, UNIQUE allocates a separate block cache.
ddcu	For magnetic tapes and Files-11 Structure Level 1 disks, ddcu specifies that $MOUNT use the ACP process currently being used by the device ddcu. The device specified must be in the format ddcu, for example, DRA3. For Files-11 Structure Level 1 disks, ddcu specifies that $MOUNT take the block allocation from the specified device.
filespec	Specifies that $MOUNT create a new process to execute the ACP image with the file specification filespec. Wildcard characters are not allowed in the file specification. The file must be in the disk and directory specified by the logical name SYS$SYSTEM. This operation requires CMKRNL privilege.