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The allocatable device name, sometimes called the allocation-class device name, uniquely identifies each device that is currently accessible to any given node in an OpenVMS cluster or to a single-node OpenVMS system. This item code generates the same name on every system for a device that is accessible on multiple cluster nodes through multiple paths or servers.
The device name string returned by the DVI$_ALLDEVNAM item code is recommended for use with the $ASSIGN service, regardless of whether the system is clustered or whether the device is cluster accessible, because it returns the same string value for all conditions.
Another possible use for the DVI$_ALLDEVNAM item code might be an application wherein processes need to coordinate their access to devices (not volumes) using the lock manager. In this case, the program would make the device a resource to be locked by the lock manager, specifying as the resource name the following concatenated components: (1) a user facility prefix followed by an underscore character and (2) the allocatable device name of the device.
Depending on the device type and characteristics, the format of the returned name may include an allocation class or node name prefix.
Use the name returned by the DVI$_DEVLOCKNAM item code to coordinate access to volumes.
The allocation class provides a way for you to access dual-pathed devices through either of the hosts that act as servers to the cluster. In this way, if one host of an allocation class set is not available, you can gain access to a device specified by that allocation class through the other host of the allocation class. You do not have to be concerned about which host of the allocation class provides access to the device. Specifically, the device name string has the following format:
|
$allocation_class$device_name |
For a detailed discussion of allocation classes, see HP OpenVMS Cluster Systems.
The host is the node that makes the device available to other nodes in the OpenVMS Cluster system. A host node can be a VMS system with an MSCP server or an HSC50 controller.
A dual-pathed device is one that is made available to the cluster by two hosts. Each of the hosts provides access (serves a path) to the device for users. One host serves the primary path; the other host serves the alternate path. The primary path is the path that the system creates through the first available host.
Do not be concerned with which host provides access to the device. When accessing a device, you specify the allocation class of the desired device, not the name of the host that serves it.
If the host serving the primary path fails, the system automatically creates a path to the device through the alternate host.
For more information about hosts, dual-pathed devices, and primary and alternate paths, see the description of the DVI$_ALT_HOST_AVAIL item code.
Storage devices are served within an OpenVMS Cluster utilizing the SCS protocol, with the server running on a remote OpenVMS system or on an SCS-capable storage controller. The alternate host type value displayed is determined from the local cluster storage hardware configuration, and indicates the type of devices serving the storage for the available SCS path or paths to the particular storage device.
Item codes in this group include: DVI$_HOST_TYPE, DVI$_ALT_HOST_TYPE, DVI$_HOST_AVAIL, and DVI$_ALT_HOST_AVAIL. Also related is DVI$_HOST_NAME.
HP suggests this item code be used solely for display purposes, and do not use it during an attempt to determine the particular cluster hardware configuration.
| Symbol | Description |
|---|---|
| DEV$V_REC | Device is record oriented. |
| DEV$V_CCL | Device is a carriage control device. |
| DEV$V_TRM | Device is a terminal. |
| DEV$V_DIR | Device is directory structured. |
| DEV$V_SDI | Device is single-directory structured. |
| DEV$V_SQD | Device is sequential and block oriented. |
| DEV$V_SPL | Device is being spooled. |
| DEV$V_OPR | Device is an operator. |
| DEV$V_RCT | Disk contains Revector Cache Table (RCT). This bit is set for every DSA disk. |
| DEV$V_NET | Device is a network device. |
| DEV$V_FOD | Device is files oriented. |
| DEV$V_DUA | Device is dual ported. |
| DEV$V_SHR | Device is shareable. |
| DEV$V_GEN | Device is a generic device. |
| DEV$V_AVL | Device is available for use. |
| DEV$V_MNT | Device is mounted. |
| DEV$V_MBX | Device is a mailbox. |
| DEV$V_DMT | Device is marked for dismount. |
| DEV$V_ELG | Device has error logging enabled. |
| DEV$V_ALL | Device is allocated. |
| DEV$V_FOR | Device is mounted foreign. |
| DEV$V_SWL | Device is software write locked. |
| DEV$V_IDV | Device can provide input. |
| DEV$V_ODV | Device can provide output. |
| DEV$V_RND | Device allows random access. |
| DEV$V_RTM | Device is a real-time device. |
| DEV$V_RCK | Device has read-checking enabled. |
| DEV$V_WCK | Device has write-checking enabled. |
Note that each device characteristic has its own individual $GETDVI item code with the format DVI$_xxxx, where xxxx are the characters following the underscore character in the symbolic name for that device characteristic.
For example, when you specify the item code DVI$_REC, $GETDVI returns a longword value that is interpreted as Boolean. If the value is 0, the device is not record oriented; if the value is 1, it is record oriented. This information is identical to that returned in the DEV$V_REC bit of the longword vector specified by the DVI$_DEVCHAR item code.
The buffer must specify a longword for all of these device-characteristic item codes.
| Symbol | Description |
|---|---|
| DEV$V_CLU | Device is available clusterwide. |
| DEV$V_DET | Device is detached terminal. |
| DEV$V_RTT | Device has remote terminal UCB extension. |
| DEV$V_CDP | Dual-pathed device with two UCBs. |
| DEV$V_2P | Two paths are known to this device. |
| DEV$V_MSCP | Device accessed using MSCP (disk or tape). Before using this bit to differentiate between types of disk and tape devices, be sure that no other more appropriate differentiation mechanism exists. |
| DEV$V_SSM | Device is a shadow set member. |
| DEV$V_SRV | Device is served by the MSCP server. |
| DEV$V_RED | Device is redirected terminal. |
| DEV$V_NNM | Device has node$ prefix. |
| DEV$V_WBC | Device supports write-back caching. |
| DEV$V_WTC | Device supports write-through caching. |
| DEV$V_HOC | Device supports host caching. |
| DEV$V_LOC | Device accessible by local (non-emulated) controller. |
| DEV$V_DFS | Device is DFS-served. |
| DEV$V_DAP | Device is DAP accessed. |
| DEV$V_NLT | Device is not-last-track; that is, it has no bad block. Information is on its last track. |
| DEV$V_SEX | Device (tape) supports serious exception handling. |
| DEV$V_SHD | Device is a member of a host-based shadow set. |
| DEV$V_VRT | Device is a shadow set virtual unit. |
| DEV$V_LDR | Loader present (tapes). |
| DEV$V_NOLB | Device ignores server load balancing requests. |
| DEV$V_NOCLU | Device will never be available clusterwide. |
| DEV$V_VMEM | Virtual member of a constituent set. |
| DEV$V_SCSI | Device is a SCSI device. |
| DEV$V_WLG | Device has write-logging capability. |
| DEV$V_NOFE | Device does not support forced error. |
| Symbol | Description |
|---|---|
| DC$_DISK | Disk device |
| DC$_TAPE | Tape device |
| DC$_SCOM | Synchronous communications device |
| DC$_CARD | Card reader |
| DC$_TERM | Terminal |
| DC$_LP | Line printer |
| DC$_REALTIME | Real-time |
| DC$_MAILBOX | Mailbox |
| DC$_MISC | Miscellaneous device |
| DC$_BUS | Peripheral adapter |
Note that, for terminals only, individual $GETDVI item codes are provided for most of the informational items returned in the DVI$_DEVDEPEND longword bit vector. The names of these item codes have the format DVI$_TT_xxxx, where xxxx is the characteristic name. The same characteristic name follows the underscore character in the symbolic name for each bit (defined by the $TTDEF macro) in the DVI$_DEVDEPEND longword. For example, the DVI$_TT_NOECHO item code returns the same information as that returned in the DVI$_DEVDEPEND bit whose symbolic name is TT$V_NOECHO.
Each such item code requires that the buffer specify a longword value, which is interpreted as Boolean. A value of 0 indicates that the terminal does not have that characteristic; a value of 1 indicates that it does.
The list of these terminal-specific item codes follows this list of item codes.
Note that, for terminals only, individual $GETDVI item codes are provided for most of the informational items returned in the DVI$_DEVDEPEND2 longword bit vector. As with DVI$_DEVDEPEND, the same characteristic name appears in the item code as appears in the symbolic name defined for each bit in the DVI$_DEVDEPEND2 longword, except that in the case of DVI$_DEVDEPEND2, the symbolic names for bits are defined by the $TT2DEF macro.
The list of these terminal-specific item codes follows this list of item codes.
The item code is applicable to all disk volumes and volume sets: mounted, not mounted, mounted shared, mounted private, or mounted foreign.
The device lock name is assigned to a volume when it is first mounted, and you cannot change this name, even if the volume name itself is changed. This allows any process on any node in an OpenVMS Cluster system to access a uniquely identified volume.
One use for the device lock name might be in an application wherein processes need to coordinate their access to files using the lock manager. In this case, the program would make the file a resource to be locked by the lock manager, specifying as the resource name the following concatenated components: (1) a user facility prefix followed by an underscore character, (2) the device lock name of the volume on which the file resides, and (3) the file ID of the file.
Although DVI$_DEVNAM returns a displayable device name, it might not return a unique name for cluster-accessible devices. For this reason, the DVI$_DEVNAM item code is not recommended for use with the $ASSIGN service. Use the DVI$_ALLDEVNAM item code with the $ASSIGN service.
Depending on the device type and characteristics, the format of the returned name may include an allocation class or node name prefix.
The DVI$_DEVNAM item code is provided solely for compatibility with existing programs from previous OpenVMS releases; therefore, HP recommends that you use the DVI$_ALLDEVNAM, DVI$_FULLDEVNAM, or DVI$_DISPLAY_DEVNAM item codes, depending on the function required.
This information allows you to determine if a function works on remote disk devices with DFS. Access control lists (ACLs), for example, cannot be set or displayed on local disk devices with DFS.
The format of the returned name includes the allocatable device name for the device (see DVI$_ALLDEVNAM) followed by any current primary or secondary path information for the device.
Depending on the device type and characteristics, the format of the returned name may include an allocation class or node name prefix.
The device name string returned by the DVI$_DISPLAY_DEVNAM item code cannot be used for the $ASSIGN service. Use the DVI$_ALLDEVNAM item code to form the device name for the $ASSIGN service.
On Alpha and Integrity server systems, this item code can be used with the PATHNAME parameter. If the PATHNAME parameter is omitted, the summation of the error counts for all paths in a multipath device is returned (which was the behavior prior to the introduction of the PATHNAME parameter). If the PATHNAME parameter is specified, only the error count for that path is returned.
DVI$_FULLDEVNAM returns a displayable device name, which includes appropriate identification to distinguish cluster-accessible devices by including the allocation class or node name in the device string.
One use for the DVI$_FULLDEVNAM item code might be to retrieve the name of a device in order to have that name displayed on a terminal. However, do not use this name as a resource name in input to the lock manager; instead, use the name returned by the DVI$_DEVLOCKNAM item code for locking volumes and the name returned by DVI$_ALLDEVNAM for locking devices.
Depending on the device type and characteristics, the format of the returned name may include an allocation class or node name prefix.
The name returned by the DVI$_FULLDEVNAM item code can be used for the $ASSIGN service. HP recommends that you use the DVI$_ALLDEVNAM item code to form the name for the $ASSIGN service, so that the name appears the same regardless of which OpenVMS Cluster node is accessing the device.
For more information about hosts, dual-pathed devices, and primary and alternate paths, see the description of the DVI$_ALT_HOST_AVAIL item code.
For more information about hosts, dual-pathed devices, and primary and alternate paths, see the description of the DVI$_ALT_HOST_AVAIL item code.
For more information about hosts, dual-pathed devices, and primary and alternate paths, see the description of the DVI$_ALT_HOST_AVAIL item code.
Storage devices are served within an OpenVMS Cluster utilizing the SCS protocol, with the server running on a remote OpenVMS system or on an SCS-capable storage controller. The host type value displayed is determined from the local cluster storage hardware configuration, and indicates the type of devices serving the storage for the available SCS path or paths to the particular storage device.
Item codes in this group include: DVI$_HOST_TYPE, DVI$_ALT_HOST_TYPE, DVI$_HOST_AVAIL, and DVI$_ALT_HOST_AVAIL. Also related is DVI$_HOST_NAME.
HP suggests this item code be used solely for display purposes; do not use it during an attempt to determine the particular cluster hardware configuration.
The device drivers for the following adapters do not maintain the link status: DEMNA, any TURBOchannel adapter, any PCMCIA adapter, any Token Ring adapter, Galaxy shared memory, TGEC, DE205, DE422, DE425, DE434, DE435, DE500-XA. (The -AA and -BA variants are supported.)
This item is supported only on newer adapters. To determine whether or not a particular LAN device supports DVI$_LAN_LINK_UP, you must first call $GETDVI using the item code DVI$_LAN_LINK_STATE_VALID. For more information, see that item code.
If DVI$_LAN_LINK_UP is used on an adapter that does not maintain the link status, the returned status from $GETDVI will be SS$_UNSUPPORTED. For more information, see DVI$_LAN_LINK_VALID.
For example, a node with a DECnet Phase IV address of 3.31 gives a decimal representation of 3103 (the value corresponding to the system parameter SCSSYSTEMID) and a hexadecimal representation of 0C1F. If DECnet Phase IV is started on this system, the MAC address of any LAN adapter on this system running DECnet is AA-00-04-00-1F-0C. < PARAMITEM>(DVI$_LAN_PROMISCUOUS_MODE) On Alpha and Integrity server systems, returns an unsigned longword, which is interpreted as Boolean. A value of 1 indicates that the device is enabled to receive all packets, not just packets addressed to the MAC address and enabled multicast addresses.
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