Device Name

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Device Name refers to identification of peripheral devices on OpenVMS systems and device naming conventions. For DEVICE_NAMING system parameter, see DEVICE_NAMING.

A device name is a string that uniquely identifies a device such as a disk, tape, network controller, terminal etc. on an OpenVMS system.


Parts of an OpenVMS device name include:

The same SCSI disk, DKA300:, could be represented as $1$GKA300:, TEST$DKA300:, or simply DKA300: depending on the device naming format (see below).


There are three general formats for naming devices depending on the use of clustering and multipath configurations:

  • ddcu - when there is no clustering or multipath devices, e.g. DKA100:
  • node$ddcu - when there is clustering, e.g. TEST$DKA100:
  • $allocation-class$ddcu - when there is clustering and/or multipath devices, e.g. $30$DKA100:

If a device name is preceded by an underscore, this means that the name is a physical device name, not a logical name.

Device Naming Conventions

Allocation Class

Allocation Class is used to uniquely identify shared devices in multipath and cluster configurations. Please see ALLOCATION_CLASS for more information. If allocation classes are used, the format for device names is as follows: $allocation-class$device-name.


An OpenVMS Cluster device name includes the name of the node to which the device is attached and the physical device name, separated by a dollar sign ($). For example, TEST$DKA1 refers to disk DKA1 on node TEST. Allocation classes should be used in multipath configurations.

Device Type

Device Type Meaning Example
CM IPMI device CMA0:
D Disk
DG Fibre Channel disk DGA100:
DK SCSI disk DKA100: - SCSI disk
DS Disk Stripe set (e.g. a shadowed disk) DSA0:
DU Disk connected to MSCP controllers DUA0:
E Ethernet Network Device
EC Ethernet Network Device
EF Ethernet Network Device
EQ Ethernet Network Device
ES Ethernet Network Device
ET Ethernet Network Device
EX Ethernet Network Device
EW Ethernet network adapter connected to PCI EWA0:
EZ Ethernet Network Device
FC Ethernet Network Device
FG Fiber Channel Host Bus Adapter FGA0:
FX Ethernet Network Device
FT Network Terminal
GG Medium Changer
GH DECwindows output device GHA0:
I Token Ring
KB Terminal KBD0:
LT LAT Network Terminal
LM SCSI tape LMA0:
MB Mailbox MBA0:
MG Fibre Channel tape drive MGA300
MK SCSI Tape Drive
MO Terminal MOU0:
MT Tape Drive
MU Tape Drive
NTY Network Terminal
OP Operator's console OPA0: - default operator's console
PK SAS controller PKA0:
RT DECnet Terminal (created with the SET HOST command)
SE ACPI system event SEA0:
T Terminal TNA0:
VT Virtual Terminal
XQ Emulated Ethernet card (DELQA-T (M7516-YM), DELQA (M7516) and DEQNA (M7504) Q-bus Ethernet cards)
XU Emulated Ethernet card (Digital's DEUNA (M7792/M7793) and DELUA (M7521) Unibus Ethernet cards)

Controller Designation

The third letter represents controller designation (in the order detected by hardware): A - first controller, B - second controller, etc. Pseudo-controllers and indirect controllers (shadow, SAN) always use A.

Unit Number

SCSI disks often have unit numbers that are multiples of 100: DKA100:, DKA200:, DKA300 etc. For tapes on parallel SCSI, the device name of a directly attached tape implies the physical location of the device; for example, MKB301 resides on bus B, SCSI target ID 3, and LUN 1. Such a naming scheme does not scale well for Fibre Channel configurations, in which the number of targets or nodes can be very large.