UCL Lexical functions - F$GETDVI

F$GETDVI is the UCL wrapper for the SYS_GETDVI system call. We briefly introduced this system call back in article 62. Here is the definition:

F$GETDVI returns a specific piece of information about the specified device.

Format
F$GETDVI(devicename,item{,pathname})

Return Value
Either an integer or a string, depending upon the item requested. The table below indicates the valid items and the corresponding return values.

Arguments
devicename

Specifies the name of the device for which you are requesting information.

item

Specifies the type of device information to return. See the table below.

pathname

Specifies the path name for a multipath-capable device. If specified, it is validated against the existing paths for the specified device. If such path does not exist, an error is returend - even if the requested item doesn't make use of the path name.

Description
F$GETDVI invokes the GETDVI system service to return information on the specified device. Use F$DEVICE to iterate through available devices. In addition to the items returned by the GETDVI system service, "EXISTS" is also a valid item for F$GETDVI. The following table lists all valid items.

Item	Information returned
ACCESSTIME_RECORDED	TRUE if volume supports recording of access times. FALSE otherwise.
ACPPID	Ancilllary control process (ACP) identification.
ACPTYPE	ACP type code: F11V1, F11V12, F11V3, F11V4, F11V5, F64, HBS, JNL, MTA, NET, REM, UCX, or ILLEGAL. ILLEGAL is returned if the device is not mounted, mounted using /FOREIGN, or the ACPTYPE is not defined.
ALL	TRUE if the device is allocated. FALSE otherwise.
ALLDEVNAM	Allocation class device name
ALLOCLASS	Allocation class of the host.
ALT_HOST_AVAIL	TRUE if host serving the alternate path is available. FALSE otherwise.
ALT_HOST_NAME	Name of the host serving the alternate path
ALT_HOST_TYPE	Hardware type of the host serving the alternate path.
AVAILABLE_PATH_COUNT	Number of available working paths for a multipath-capable device.
AVL	TRUE if device is available for use. FALSE otherwise.
CCL	TRUE if the device is a carriage control device. FALSE otherwise.
CLUSTER	Volume cluser size.
CONCEALED	TRUE if the logical device name translates to a concealed device. FALSE otherwise.
CYLINDERS	Number of cylinders on the volume (local disks only).
DEVBUFSIZ	Device buffer size.
DEVCHAR	Device characteristics.
DEVCHAR2	Additional device characteristics.
DEVCLASS	Device class.
DEVDEPEND	Device dependent information.
DEVDEPEND2	Additional device dependent information.
DEVICE_MAX_IO_SIZE	The maximum contiguous transfer size supported by the device driver. Note that other software layers, such as RMS, may impose a smaller size.
DEVICE_TYPE_NAME	Device type name. For some hardware, such as SCSI, the device type is retrieved from the hardware device itself.
DEVLOCKNAM	A unique lock name for the device.
DEVNAM	Device name.
DEVSTS	Device status.
DEVTYPE	Device type.
DFS_ACCESS	TRUE to indicate a remote virtual disk. FALSE otherwise.
DIR	TRUE if the device is file structured. FALSE otherwise.
DMT	TRUE if device is marked for dismount. FALSE otherwise.
DUA	TRUE if device is generic. FALSE otherwise.
ELG	TRUE if device has error logging enabled.
ERASE_ON_DELETE	TRUE if files are zeroed upon deletion on the volume. FALSE otherwise.
ERRCNT	Error count on device. If pathname is specified, the count is only for that pathname, otherwise it is the aggregate for all paths.
ERROR_RESET_TIME	Time at which the error count was reset
EXISTS	TRUE if the device exists on the system. FALSE otherwise.
EXPSIZE	Current expansion limit on the volume.
FC_HBA_FIRMWARE_REV	Same as FIRMWARE.
FC_NODE_NAME	Fibre Channel host bus adapter node name.
FC_PORT_NAME	Fibre Channel host bus adapter port name.
FIRMWARE_REV	Hardware firmware revision information. If hardware doesn't support this, a null string is returned.
FOD	TRUE if the device is a files-oriented device. FALSE otherwise.
FOR	TRUE if the device is mounted using /FOREIGN. FALSE otherwise.
FREEBLOCKS	Number of free space on the volume (disks only).
FULLDEVNAM	Fully qualified device name.
GEN	TRUE If device is generic. FALSE otherwise.
HARDLINKS_SUPPORTED	TRUE if volume's file system supports POSIX hardlinks. FALSE otherwise.
HOST_AVAIL	TRUE if host serving the primary path is available. FALSE otherwise.
HOST_COUNT	Number of hosts that make the device available to a UOS Cluster.
HOST_NAME	Name of the host serving the primary path.
HOST_TYPE	Hardware type of the host serving the primary path.
IDV	TRUE if the device is capable of producing input. FALSE otherwise.
LAN_ALL_MULTICAST_MODE	TRUE if the device is enabled to receive all multicast packets rather than only packets addressed to the enabled multicast addresses. FALSE otherwise.
LAN_AUTONEG_ENABLED	TRUE if device is set to autonegotiate the speed and duplex settings. FALSE otherwise.
LAN_DEFAULT_MAC_ADDRESS	The default MAC address of the device. Null is returned for non-network devices.
LAN_FULL_DUPLEX	TRUE if the device is operating in full-duplex mode. FALSE otherwise.
LAN_JUMBO_FRAMES_ENABLED	TRUE if jumbo frames are enabled. FALSE otherwise.
LAN_LINK_STATE_VALID	TRUE if the device driver correctly maintains the link status. FALSE otherwise.
LAN_LINK_UP	TRUE if the link is up. FALSE otherwise.
LAN_MAC_ADDRESS	Current MAC address of the device. Null is returned for non-network devices.
LAN_PROMISCUOUS_MODE	TRUE if device is enabled to receive all packets rather than those matching its MAC. FALSE otherwise.
LAN_PROTOCOL_NAME	Name of the LAN protocol running on the device. Null is returned for non-network devices.
LAN_PROTOCOL_TYPE	Type of LAN protocol running on the device. Null is returned for non-network devices.
LAN_SPEED	Speed of the LAN device in megabits per second. Null is returned for non-network devices.
LOCKID	Clusterwise lock identification.
LOGVOLNAM	Logical volume name.
MAILBOX_BUFFER_QUOTA	Current mailbox quota.
MAILBOX_INITIAL_QUOTA	Initial mailbox quota.
MAXBLOCK	Size of volume in bytes.
MAXFILES	Maximum number of files on volume (disks only). 0 if no limit.
MBX	TRUE if device is a mailbox. FALSE otherwise.
MEDIA_ID	Non-decoded media ID. Null if no media on device.
MEDIA_NAME	Name of media type.
MEDIA_TYPE	Device name prefix.
MNT	TRUE if the device is mounted. FALSE otherwise.
MOUNT_TIME	Time at which the device was mounted.
MOUNTCNT	Number of times the device has been mounted on the local system.
MOUNTVER_ELIGIBLE	TRUE if the volume is eligible to udnergo mount verification. FALSE otherwise.
MPDEV_AUTO_PATH_SW_CNT	Number of times a multipath device has autmatically switched paths due to I/O errors or due to falling back to a local path from a remote path.
MPDEV_CURRENT_PATH	Current path name for multipath devices. If the device is not part of a multipath set, this returnes the name of the device path. Returns null string if device doesn't support multipathing.
MPDEV_MAN_PATH_SW_CNT	Number of times a multipath device has manually switched paths.
MT3_DENSITY	Current density of the tape.
MT3_SUPPORTED	TRUE if device supports densities. FALSE otherwise.
MULTIPATH	TRUE if the device is a member of a multipath set. FALSE otherwise.
MVSUPMSG	TRUE if mount verification OPCOM messages are currently supressed on this device. FALSE otherwise.
NET	TRUE if device is a network device. FALSE otherwise.
NEXTDEVNAM	Device name of the next volume in a volume set (disks only).
NOCACHE_ON_VOLUME	TRUE if device is mounted with no caching. FALSE otherwise.
NOHIGHWATER	TRUE if high-water marking is disabled on the device. FALSE otherwise.
NOSHARE_MOUNTED	TRUE if the volume is mounted with /NOSHARE. FALSE otherwise.
ODS2_SUBSET0	TRUE if volume mounted on the device only supports a subset of the ODS-2 file structure.
ODS5	TRUE if volume is mounted OS5. FALSE otherwise.
ODV	TRUE if device is capable of providing output.
OPCNT	Operation count of the device. If the pathname is specified, only the operation count for that path is returned. Otherwise, the aggregate count for all paths is returned.
OPR	TRUE if the device is an operator. FALSE otherwise.
OWNUIC	Owner ID of the device owner.
PATH_AVAILABLE	TRUE if the specified path is vailable. FALSE otherwise. If pathname is omitted, information about the current path of the device is returned.
PATH_NOT_RESPONDING	TRUE if the specified path is marked as not responding. FALSE otherwise. If pathname is omitted, information about the current path of the device is returned.
PATH_POLL_ENABLED	TRUE if the specified path is enabled for multipath polling. FALSE otherwise. If pathname is omitted, information on the current path of the device is returned.
PATH_SWITCH_FROM_TIME	Time from which this path was switched.
PATH_SWITCH_TO_TIME	Time to which this path was switched.
PATH_USER_DISABLED	TRUE if specified path has been disabled. FALSE otherwise. If pathname is omitted, information on the current path of the device is returned.
PID	Process ID of the device owner.
PREFERRED_CPU	A 64-bit integer where the corresponding CPU index that is the preferred CPU for this device is set to 1.
PREFERRED_CPU_BITMAP	Equivalent to PREFERRED_CPU except that the result is a string of 0s and 1s corresponding to the bits returned by PREFERRED_CPU.
PROT_SUBSYSTEM_ENABLED	TRUE if the device is mounted with the protection subsystems enabled. FALSE otherwise.
QLEN	Current queue length of the device. This is the number of I/O requests in the device's driver.
RCK	TRUE if the device has reach checking enabled. FALSE otherwise.
RCT	TRUE if the disk contains RCT. FALSE otherwise.
REC	TRUE if the device is record oriented. FALSE otherwise.
RECSIZ	Current maximum blocked record size of device, in bytes.
REFCNT	Reference count of processes using the device.
REMOTE_DEVICE	TRUE if the device is remote. FALSE otherwise.
RND	TRUE if device allows random access. FALSE otherwise.
ROOTDEVNAME	Device name of the root volume in a volume set (disks only).
RTM	TRUE if the device is real-time. FALSE otherwise.
SCSI_DEVICE_FIRMWARE_REV	Firmware revision number of a SCSI device. Null returned for other devices.
SDI	TRUE if the device is single-directory structured. FALSE otherwise.
SECTORS	Number of sectors per track (disks only). 0 is returned for disks without those metrics available (such as virtual disks).
SERIALNUM	Volume serial number (disks only). For non-disks, if the device reports a serial number, it is returned here. Otherwise null.
SERVED_DEVICE	TRUE if this is a served device. FALSE otherwise.
SET_HOST_TERMINAL	TRUE if the device is a remote terminal from a remote node (via SET HOST). FALSE otherwise.
SHDW_CATCHUP_COPYING	TRUE if the device is a member that is the target of a full copy operation. FALSE otherwise.
SHDW_COPIER_NODE	The name of the node that is actively performing the copy or merge operation.
SHDW_DEVICE_COUNT	The total number of devices in the shadow set, including devices being added as copy targets.
SHDW_GENERATION	Current internal revision number for the shadow set.
SHDW_MASTER	TRUE if this device is a shadow set.
SHDW_MASTER_MBR	Name of master member unit used for merge, copy repair, and recovery operations.
SHDW_MASTER_NAME	Device name representing the name of the shadow set that this device belongs to.
SHDW_MBR_COPY_DONE	The percent of the copy operation completed on this shadow set member unit.
SHDW_MBR_COUNT	The total number of devices in the shadow set, not including devices being added as copy targets.
SHDW_MBR_MERGE	The percent of the merge operation complete on this member unit.
SHDW_MBR_READ_COST	Read cost value for this unit in the shadow set.
SHDW_MEMBER	TRUE if the device is a member of a shadow set. FALSE otherwise.
SHDW_MERGE_COPYING	TRUE if the device is a merge member of a shadow set.
SHDW_MINIMERGE_ENABLE	TRUE if the device will undergo a min-merge instead of a full merge, if a system in the cluster crashes.
SHDW_NEXT_MBR_NAME	Device name of the next member in the shadow set. If the virtual shadow set device name is passed, the first device in the shadow set is returned. If there are no more members, null is returned.
SHDW_READ_SOURCE	The name of the member unit that will be used for reads at this time. This will be the unit with the lowest sum of queue length and read cost.
SHDW_SITE	The site value for the device. This is set by SET DEVICE or SET SHADOW.
SHDW_TIMEOUT	The user-specified timeout value st for the device. If not set, the system default value is used.
SHR	TRUE if the device is shareable. FALSE otherwise.
SPL	TRUE if the device is being spooled. FALSE otherwise.
SPLDEVNAME	Name of the device being spooled.
SQD	TRUE if the device is sequential block-oriented.
STS	Status information.
SWL	TRUE if the device is software write-locked. FALSE otherwise.
TOTAL_PATH_COUNT	Number of paths for a multipath device.
TRACKS	Number of tracks per cylinder (disks only). Will return 0 if the disk has no metrics (such as virtual disks).
TRANSCNT	Volume transaction count.
TRM	TRUE if the device is a terminal. FALSE otherwise.
TT_ACCPORNAM	The terminal server name and port name.
TT_ALTYPEAHD	TRUE if the terminal has an alternate type-ahead buffer.
TT_ANSICRT	TRUE if the terminal is an ANSI video terminal.
TT_APP_KEYPAD	TRUE if the terminal is in keypad applications mode.
TT_AUTOBAUD	TRUE if the terminal has automatic baud rate detection.
TT_AVO	TRUE if the terminal has AVO (VT100-family).
TT_BLOCK	TRUE if the terminal has block mode capability.
TT_BRDCSTMBX	TRUE if terminal uses mailbox broadcast messages.
TT_CHARSET	A bitmap indicating the coded character set supported by the terminal.
TT_CRFILL	TRUE if the terminal requires fill after CR.
TT_CS_HANGUL	TRUE if terminal supports the Hangul character set.
TT_CS_HANYU	TRUE if terminal supports the Hanyu character set.
TT_CS_HANZI	TRUE if terminal supports the Hanzi character set.
TT_CS_KANA	TRUE if terminal supports the Kana character set.
TT_CS_KANJI	TRUE if terminal supports the Kanji character set.
TT_CS_THAI	TRUE if terminal supports the Thai character set.
TT_DECCRT	TRUE if terminal is a DEC CRT terminal.
TT_DECCRT2	TRUE if terminal is a DEC CRT2 terminal.
TT_DECCRT3	TRUE if terminal is a DEC CRT3 terminal.
TT_DECCRT4	TRUE if terminal is a DEC CRT4 terminal.
TT_DIALUP	TRUE if terminal is connected to dialup.
TT_DISCONNECT	TRUE if the terminal can be disconnected.
TT_DMA	TRUE if terminal has direct memory access mode.
TT_DRCS	TRUE if the terminal supports loadable character fonts.
TT_EDIT	TRUE if the terminal edit flag is set.
TT_EDITING	TRUE if advanced editing is enabled.
TT_EIGHTBIT	TRUE if the terminal uses 8-bit ASCII character set.
TT_ESCAPE	TRUE if terminal generates escape sequences.
TT_FALLBACK	TRUE if the terminal uses the multinational fallback option.
TT_HALFDUP	TRUE if terminal is in half-duplex mode.
TT_HANGUP	TRUE if the hangup flag is set.
TT_HOSTSYNC	TRUE if the terminal uses host/terminal sync communication.
TT_INSERT	TRUE if insert mode is the default line editing mode.
TT_LFFILL	TRUE if terminal requires fill after LF.
TT_LOCALECHO	TRUE if terminal has local echo set.
TT_LOWER	TRUE if the terminal supports lowercase letters.
TT_MBXDSABL	TRUE if mailboxes associated with the termainl will receive unsolicited input or input notification.
TT_MECHFORM	TRUE if terminal has mechanical FF.
TT_MECHTAB	TRUE if terminal has mechanical tabs (HT).
TT_MODEM	TRUE if terminal is connected to a modem.
TT_MODHANGUP	TRUE if the modify hangup characterstic is set.
TT_NOBRDCST	TRUE if terminal will not receive briacast messages.
TT_NOECHO	TRUE if input characters are not echoed.
TT_NOTYPEAHD	TRUE if data must be solicited by a read operation.
TT_OPER	TRUE if terminal is an operations terminal.
TT_PAGE	Terminal page/screen height.
TT_PASTHRU	TRUE if PASALL mode with flow control is available.
TT_PHYDEVNAM	Physical device name associated with a handle or a virtual terminal.
TT_PRINTER	TRUE if the terminal has a printer port.
TT_READSYNC	TRUE if the terminal has read synchronization.
TT_REGIS	TRUE if the terminal has ReGID graphics.
TT_REMOTE	TRUE if terminal has established modem control.
TT_SCOPE	True if the terrminal is a video terminal.
TT_SECURE	TRUE if the terminal can recognize a secure server.
TT_SETSPEED	TRUE if the terminal line speed can be set.
TT_SIXEL	TRUE if the sixel is supported.
TT_SYSPWD	TRUE if the system password is enabled for this terminal.
TT_TTSYNC	TRUE if there is terminal/host synchronization.
TT_WRAP	TRUE if CRLF should be inserted if the cursor moves beyond the right margin.
UNIT	Unit number of device.
VOLCHAR	128-bit string indicating the volume characteristics/capabilities. If a bit is set, the feature is supported.
VOLCOUNT	Count of volumes in a volume set.
VOLNAM	Volume name the device is part of.
VOLNUMBER	Number of the current volume in a volume set.
VOLSETMEM	TRUE if the device belongs to a volume set.
VOLSIZE	The current logical volume size.
VOLUME_EXTEND_QUANTITY	Number of bytes that files on the volume are extended by.
VOLUME_MOUNT_GROUP	TRUE if the volume is mounted /GROUP.
VOLUME_MOUNT_SYS	TRUE if volume is mounted /SYSTEM.
VOLUME_PENDING_WRITE_ERR	Number of pending write errors on device.
VOLUME_RETAIN_MAX	Maximum retention time for the volume (via SET VOLUME/RETENTION).
VOLUME_RETAIN_MIN	Minimum retention time for the volume (via SET VOLUME/RETENTION).
VOLUME_SPOOLED_DEV_CBT	The number of devices spooled to the volume.
VOLUME_WINDOW	Default window size for the volume.
VPROT	VOlume protection mask.
WCK	TRUE if the device has write-checking enabled.
WRITETHRU_CACHE_ENABLED	TRUE if volume is mounted with write-through caching enabled.
WWID	Worldwide identifier for a Fibre Channel device.

Example
$ X = F$GETDVI("_DISKA0:","ERRCNT")
This would set X to the error count of DISKA0:.

$ X = F$GETDVI("_TERMA0:","DEVCLASS")
This would set X to "TERM".

        Function_GetDVI : begin
                              if( Missing_Parentheses( '(' ) ) then
                              begin
                                  exit ;
                              end ;
                              if( Parse_GetDVI( Err, Context ) ) then
                              begin
                                  exit ;
                              end ;
                              if( Missing_Parentheses( ')' ) ) then
                              begin
                                  exit ;
                              end ;
                              S := Context ;
                          end ;

// SYS_DVI descriptor codes...
const DVI_DEVCHAR = 1 ; // Get device characteristics
      DVI_ACCESSTIME_RECORDED = 2 ;
      DVI_ACPPID = 3 ;
      DVI_ACPTYPE = 4 ;
      DVI_ALL = 5 ;
      DVI_ALLDEVNAM = 6 ;
      DVI_ALLOCLASS = 7 ;
      DVI_ALT_HOST_AVAIL = 8 ;
      DVI_ALT_HOST_NAME = 9 ;
      DVI_ALT_HOST_TYPE = 10 ;
      DVI_AVAILABLE_PATH_COUNT = 11 ;
      DVI_AVL = 12 ;
      DVI_CLUSTER = 13 ;
      DVI_CONCEALED = 14 ;
      DVI_CYLINDERS = 15 ;
      DVI_DEVBUFSIZ = 16 ;
      DVI_DEVCHAR2 = 17 ;
      DVI_DEVCLASS = 18 ;
      DVI_DEVDEPEND = 19 ;
      DVI_DEVDEPEND2 = 20 ;
      DVI_DEVICE_MAX_IO_SIZE = 21 ;
      DVI_DEVICE_TYPE_NAME = 22 ;
      DVI_DEVLOCKNAM = 23 ;
      DVI_DEVNAM = 24 ;
      DVI_DEVSTS = 25 ;
      DVI_DEVTYPE = 26 ;
      DVI_DFS_ACCESS = 27 ;
      DVI_ERASE_ON_DELETE = 28 ;
      DVI_ERRCNT = 29 ;
      DVI_ERROR_RESET_TIME = 30 ;
      DVI_EXISTS = 31 ;
      DVI_EXPSIZE = 32 ;
      DVI_FC_HBA_FIRMWARE_REV = 33 ;
      DVI_FC_NODE_NAME = 34 ;
      DVI_FC_PORT_NAME = 35 ;
      DVI_FIRMWARE_REV = 36 ;
      DVI_FREEBLOCKS = 37 ;
      DVI_FULLDEVNAM = 38 ;
      DVI_HARDLINKS_SUPPORTED = 39 ;
      DVI_HOST_AVAIL = 40 ;
      DVI_HOST_COUNT = 41 ;
      DVI_HOST_NAME = 42 ;
      DVI_HOST_TYPE = 43 ;
      DVI_LAN_ALL_MULTICAST_MODE = 44 ;
      DVI_LAN_AUTONEG_ENABLED = 45 ;
      DVI_LAN_DEFAULT_MAC_ADDRESS = 46 ;
      DVI_LAN_FULL_DUPLEX = 47 ;
      DVI_LAN_JUMBO_FRAMES_ENABLED = 48 ;
      DVI_LAN_LINK_STATE_VALID = 49 ;
      DVI_LAN_LINK_UP = 50 ;
      DVI_LAN_MAC_ADDRESS = 51 ;
      DVI_LAN_PROMISCUOUS_MODE = 52 ;
      DVI_LAN_PROTOCOL_NAME = 53 ;
      DVI_LAN_PROTOCOL_TYPE = 54 ;
      DVI_LAN_SPEED = 55 ;
      DVI_LOCKID = 56 ;
      DVI_LOGVOLNAM = 57 ;
      DVI_MAILBOX_BUFFER_QUOTA = 58 ;
      DVI_MAILBOX_INITIAL_QUOTA = 59 ;
      DVI_MAXBLOCK = 60 ;
      DVI_MAXFILES = 61 ;
      DVI_MEDIA_ID = 62 ;
      DVI_MEDIA_NAME = 63 ;
      DVI_MEDIA_TYPE = 64 ;
      DVI_MOUNT_TIME = 65 ;
      DVI_MOUNTCNT = 66 ;
      DVI_MOUNTVER_ELIGIBLE = 67 ;
      DVI_MPDEV_AUTO_PATH_SW_CNT = 68 ;
      DVI_MPDEV_CURRENT_PATH = 69 ;
      DVI_MPDEV_MAN_PATH_SW_CNT = 70 ;
      DVI_MSCP_UNIT_NUMBER = 71 ;
      DVI_MT3_DENSITY = 72 ;
      DVI_MT3_SUPPORTED = 73 ;
      DVI_MULTIPATH = 74 ;
      DVI_MVSUPMSG = 75 ;
      DVI_NEXTDEVNAM = 76 ;
      DVI_NOCACHE_ON_VOLUME = 77 ;
      DVI_NOHIGHWATER = 78 ;
      DVI_NOSHARE_MOUNTED = 79 ;
      DVI_ODS2_SUBSET0 = 80 ;
      DVI_ODS5 = 81 ;
      DVI_OPCNT = 82 ;
      DVI_OWNUIC = 83 ;
      DVI_PATH_AVAILABLE = 84 ;
      DVI_PATH_NOT_RESPONDING = 85 ;
      DVI_PATH_POLL_ENABLED = 86 ;
      DVI_PATH_SWITCH_FROM_TIME = 87 ;
      DVI_PATH_SWITCH_TO_TIME = 88 ;
      DVI_PATH_USER_DISABLED = 89 ;
      DVI_PID = 90 ;
      DVI_PREFERRED_CPU = 91 ;
      DVI_PREFERRED_CPU_BITMAP = 92 ;
      DVI_PROT_SUBSYSTEM_ENABLED = 93 ;
      DVI_QLEN = 94 ;
      DVI_RECSIZ = 95 ;
      DVI_REFCNT = 96 ;
      DVI_REMOTE_DEVICE = 97 ;
      DVI_ROOTDEVNAME = 98 ;
      DVI_SCSI_DEVICE_FIRMWARE_REV = 99 ;
      DVI_SECTORS = 100 ;
      DVI_SERIALNUM = 101 ;
      DVI_SERVED_DEVICE = 102 ;
      DVI_SHDW_CATCHUP_COPYING = 103 ;
      DVI_SHDW_COPIER_NODE = 104 ;
      DVI_SHDW_DEVICE_COUNT = 105 ;
      DVI_SHDW_GENERATION = 106 ;
      DVI_SHDW_MASTER = 107 ;
      DVI_SHDW_MASTER_MBR = 108 ;
      DVI_SHDW_MASTER_NAME = 109 ;
      DVI_SHDW_MBR_COPY_DONE = 110 ;
      DVI_SHDW_MBR_COUNT = 111 ;
      DVI_SHDW_MBR_MERGE_DONE = 112 ;
      DVI_SHDW_MBR_READ_COST = 113 ;
      DVI_SHDW_MEMBER = 114 ;
      DVI_SHDW_MERGE_COPYING = 115 ;
      DVI_SHDW_MINIMERGE_ENABLE = 116 ;
      DVI_SHDW_NEXT_MBR_NAME = 117 ;
      DVI_SHDW_READ_SOURCE = 118 ;
      DVI_SHDW_SITE = 119 ;
      DVI_SHDW_TIMEOUT = 120 ;
      DVI_SPLDEVNAME = 121 ;
      DVI_STS = 122 ;
      DVI_TOTAL_PATH_COUNT = 123 ;
      DVI_TRACKS = 124 ;
      DVI_TRANSCNT = 125 ;
      DVI_TT_ACCPORNAM = 126 ;
      DVI_TT_ALTYPEAHD = 127 ;
      DVI_TT_ANSICRT = 128 ;
      DVI_TT_APP_KEYPAD = 129 ;
      DVI_TT_AUTOBAUD = 130 ;
      DVI_TT_AVO = 131 ;
      DVI_TT_BLOCK = 132 ;
      DVI_TT_BRDCSTMBX = 133 ;
      DVI_TT_CHARSET = 134 ;
      DVI_TT_CRFILL = 135 ;
      DVI_TT_CS_HANGUL = 136 ;
      DVI_TT_CS_HANYU = 137 ;
      DVI_TT_CS_HANZI = 138 ;
      DVI_TT_CS_KANA = 139 ;
      DVI_TT_CS_KANJI = 140 ;
      DVI_TT_CS_THAI = 141 ;
      DVI_TT_DECCRT = 142 ;
      DVI_TT_DECCRT2 = 143 ;
      DVI_TT_DECCRT3 = 144 ;
      DVI_TT_DECCRT4 = 145 ;
      DVI_TT_DIALUP = 146 ;
      DVI_TT_DISCONNECT = 147 ;
      DVI_TT_DMA = 148 ;
      DVI_TT_DRCS = 149 ;
      DVI_TT_EDIT = 150 ;
      DVI_TT_EDITING = 151 ;
      DVI_TT_EIGHTBIT = 152 ;
      DVI_TT_ESCAPE = 153 ;
      DVI_TT_FALLBACK = 154 ;
      DVI_TT_HALFDUP = 155 ;
      DVI_TT_HANGUP = 156 ;
      DVI_TT_HOSTSYNC = 157 ;
      DVI_TT_INSERT = 158 ;
      DVI_TT_LFFILL = 159 ;
      DVI_TT_LOCALECHO = 160 ;
      DVI_TT_LOWER = 161 ;
      DVI_TT_MBXDSABL = 162 ;
      DVI_TT_MECHFORM = 163 ;
      DVI_TT_MECHTAB = 164 ;
      DVI_TT_MODEM = 165 ;
      DVI_TT_MODHANGUP = 166 ;
      DVI_TT_NOBRDCST = 167 ;
      DVI_TT_NOECHO = 168 ;
      DVI_TT_NOTYPEAHD = 169 ;
      DVI_TT_OPER = 170 ;
      DVI_TT_PAGE = 171 ;
      DVI_TT_PASTHRU = 172 ;
      DVI_TT_PHYDEVNAM = 173 ;
      DVI_TT_PRINTER = 174 ;
      DVI_TT_READSYNC = 175 ;
      DVI_TT_REGIS = 176 ;
      DVI_TT_REMOTE = 177 ;
      DVI_TT_SCOPE = 178 ;
      DVI_TT_SECURE = 179 ;
      DVI_TT_SETSPEED = 180 ;
      DVI_TT_SIXEL = 181 ;
      DVI_TT_SYSPWD = 182 ;
      DVI_TT_TTSYNC = 183 ;
      DVI_TT_WRAP = 184 ;
      DVI_UNIT = 185 ;
      DVI_VOLCHAR = 186 ;
      DVI_VOLCOUNT = 187 ;
      DVI_VOLNAM = 188 ;
      DVI_VOLNUMBER = 189 ;
      DVI_VOLSETMEM = 190 ;
      DVI_VOLSIZE = 191 ;
      DVI_VOLUME_EXTEND_QUANTITY = 192 ;
      DVI_VOLUME_MOUNT_GROUP = 193 ;
      DVI_VOLUME_MOUNT_SYS = 194 ;
      DVI_VOLUME_PENDING_WRITE_ERR = 195 ;
      DVI_VOLUME_RETAIN_MAX = 196 ;
      DVI_VOLUME_RETAIN_MIN = 197 ;
      DVI_VOLUME_SPOOLED_DEV_CBT = 198 ;
      DVI_VOLUME_WINDOW = 199 ;
      DVI_VPROT = 200 ;
      DVI_WRITETHRU_CACHE_ENABLED = 201 ;
      DVI_WWID = 202 ;

// Device characteristics...
const DEV_V_ALL = 1 ; // Device is allocated.
      DEV_V_AVL = 2 ; // Device is available for use.
      DEV_V_CCL = 4 ; // Device is a carriage control device.
      DEV_V_DIR = 8 ; // Device is directory structured.
      DEV_V_DMT = 16 ; // Device is marked for dismount.
      DEV_V_DUA = 32 ; // Device is dual ported.
      DEV_V_ELG = 64 ; // Device has error logging enabled.
      DEV_V_FOD = 128 ; // Device is files oriented.
      DEV_V_FOR = 256 ; // Device is mounted foreign.
      DEV_V_GEN = 512 ; // Device is a generic device.
      DEV_V_IDV = 1024 ; // Device can provide input.
      DEV_V_MBX = 2048 ; // Device is a mailbox.
      DEV_V_MNT = 4096 ; // Device is mounted.
      DEV_V_NET = 8192 ; // Device is a network device.
      DEV_V_ODV = 16384 ; // Device can provide output.
      DEV_V_OPR = 32768 ; // Device is an operator.
      DEV_V_RCK = $10000 ; // Device has read-checking enabled.
      DEV_V_RCT = $20000 ; // Disk contains Revector Cache Table (RCT). This bit is set for each DSA disk
      DEV_V_REC = $40000 ; // Device is record oriented.
      DEV_V_RND = $80000 ; // Device allows random access.
      DEV_V_RTM = $100000 ; // Device is a real-time device.
      DEV_V_SDI = $200000 ; // Device is single-directory structured.
      DEV_V_SHR = $400000 ; // Device is shareable.
      DEV_V_SQD = $800000 ; // Device is sequential and block oriented.
      DEV_V_SPL = $1000000 ; // Device is being spooled.
      DEV_V_SWL = $2000000 ; // Device is software write locked.
      DEV_V_TRM = $4000000 ; // Device is a terminal
      DEV_V_WCK = $8000000 ; // Device has write-checking enabled.

      DEV_V_CDP = $10000000 ; // Dual-pathed device with two UCBs.
      DEV_V_2P = $20000000 ; // Two paths are known to this device.
      DEV_V_MSCP = $40000000  ; // Device accessed using MSCP (disk or tape).
      DEV_V_SSM = $80000000 ; // Device is a shadow set member.
      DEV_V_SRV = $100000000 ; // Device is served by the MSCP server.
      DEV_V_RED = $200000000 ; // Device is redirected terminal.
      DEV_V_NNM = $400000000 ; // Device has node$ prefix.
      DEV_V_WBC = $800000000 ; // Device supports write-back caching.
      DEV_V_WTC = $1000000000 ; // Device supports write-through caching.
      DEV_V_HOC = $2000000000 ; // Device supports host caching.
      DEV_V_LOC = $4000000000 ; // Device accessible by local (non-emulated) controller.
      DEV_V_DFS = $8000000000 ; // Device is DFS-served.
      DEV_V_DAP = $10000000000 ; // Device is DAP accessed.
      DEV_V_NLT = $20000000000 ; // Device is not-last-track; that is, it has no bad block. Information is on its last track.
      DEV_V_SEX = $40000000000 ; // Device (tape) supports serious exception handling.
      DEV_V_SHD = $80000000000 ; // Device is a member of a host-based shadow set.
      DEV_V_VRT = $100000000000 ; // Device is a shadow set virtual unit.
      DEV_V_LDR = $200000000000 ; // Loader present (tapes).
      DEV_V_NOLB = $400000000000 ; // Device ignores server load balancing requests.
      DEV_V_NOCLU = $800000000000 ; // Device will never be available clusterwide.
      DEV_V_VMEM = $1000000000000 ; // Virtual member of a constituent set.
      DEV_V_SCSI = $2000000000000 ; // Device is a SCSI device.
      DEV_V_WLG = $4000000000000 ; // Device has write-logging capability.
      DEV_V_NOFE = $8000000000000 ; // Device does not support forced error.

      DEV_M_DET = $10000000000000 ; // Terminal is detached
      DEV_M_RTT = $20000000000000 ; // Terminal has remote terminal UCB extension.

Now that we've described the function from a user-perspective, and defined the new constants we are using, we're ready to consider the code that implements the F$GETDVI function (Parse_GetDVI). However, given the length of this article, we'll save that for the next article.

Copyright © 2020 by Alan Conroy. This article may be copied in whole or in part as long as this copyright is included.