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 simly 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
EW Ethernet network adapter connected to PCI EWA0:
FG Fiber Channel Host Bus Adapter FGA0:
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)

Third letter

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.