The Question is:
Why does VMS see the EGA0 device on a DS25 as EWA0?
The Answer is :
The LAN device naming conventions in OpenVMS attempt to use common
names for the bus type and LAN media type, for example:
Device name first letter is
E - Ethernet
F - FDDI
I - Token Ring
H - ATM
Device name second letter is:
A - FutureBus
C - TurboChannel
E - Unibus
G - Fibre Channel
L - Emulated LAN
Q - Qbus
R - EISA or ISA bus
T - BI bus
W - PCI bus
X - XMI bus
So, PCI Ethernet devices are generally called EW which includes:
10 mbit Ethernet - DE434, DE435, DE436 (quad), DE450
10/100 mbit Ethernet - DE500, DE504 (quad)
10/100/1000 mbit Ethernet - DEGPA, DEGXA
There are exceptions to the EW device naming, with the salient
example being EI, the Intel 82558/82559 device. The SRM console
elected to use the device name EI and OpenVMS followed this
lead, in an attempt to avoid introducing additional confusion.
The SRM console for the DS25 and other systems that have Tigon 3 boot
support (AlphaServer ES40, AlphaServer ES45, AlphaServer ES47,
AlphaServer GS1280, AlphaServer DS20, and potentially other Alpha
platforms) elected to use the device name EG.
As OpenVMS expects to use the EG device name as LAN over Fibre Channel,
and especially since G is the commonly used Fibre Channel device letter,
there will be some confusion.
Given the two-character name-space for device controller prefixes,
some level of confusion is unfortunately inevitable.