topic Re: allocation between ewa0/ewb0 and physical nic in Operating System - OpenVMS

allocation between ewa0/ewb0 and physical nic

Christian Burschka — Thu, 23 Nov 2006 09:00:10 GMT

Dear experts,

I stumbled about a (at least for me) very confusing finding. But may be that You call
it normal.

On an alphastation255 with vms 6.2-1h3

with only onboard ethernet
we0/ewa0 is onboard ethernet (no question)

but

putting in a separate nic, I find, that
this one becomes ewa0

and the onboard ethernet is (suddenly)
we1/ewb0.

Is that alway so ?
Or, which parameters in my system are the reason for this allocation?

Thanks in advance,

Chris.

Re: allocation between ewa0/ewb0 and physical nic

Volker Halle — Thu, 23 Nov 2006 09:35:38 GMT

Chris,

both the console and OpenVMS have specific algorithms to scan the device buses and configure the devices found. These algorithms may even differ, which causes even more confusion, if a device called EWA0 on the cosnole will be called EWB0 under OpenVMS and vice-versa.

You cannot change this behaviour of OpenVMS autoconfiguration, but it might be possible to change the console algorithm.

That's the way it is.

Volker.

Re: allocation between ewa0/ewb0 and physical nic

Steven Schweda — Thu, 23 Nov 2006 10:20:57 GMT

Really? I don't recall seeing this on my
AlpSta 200 4/233 when I added a (fast)
Ethernet card. (But that may not prove
much.)

If the SYSGEN parameter DEVICE_NAMING existed
so long ago, it might change things.

SYSGEN HELP:

SYS_PARAMETERS

DEVICE_NAMING

(Alpha only) DEVICE_NAMING is a bit mask indicating whether port
allocation classes are used in forming SCSI device names.

Following is the bit definition:

Bit Definition

0 If 1, enable new naming.

1 Must be 0. This bit is reserved for use by HP.

As I recall, (the evil) bit 1 was the one to
set to get the VMS device names to match the
SRM console device names. (But no bets.)

Re: allocation between ewa0/ewb0 and physical nic

Volker Halle — Thu, 23 Nov 2006 10:52:28 GMT

Chris,

Steven is right. The undocumented bit 1 in the DEVICE_NAMING SYSGEN parameter seems to control, how OpenVMS scans and configures devices. You may want to test it on your system by setting DEVICE_NAMING = 2 - please report the results...

Volker.

Re: allocation between ewa0/ewb0 and physical nic

Christian Burschka — Thu, 23 Nov 2006 11:08:50 GMT

Volker, Steven,

thanks a lot for Your valuable information.

Right now I am quite happy to have my machine running again. The users are standing in line...

But I will set up a second alphastation
in just the same way, where I can play around with parameters and without the danger of spoiling something. Just next Week.

And I will report here what I find. OK?

Many regards

Chris.

Re: allocation between ewa0/ewb0 and physical nic

Richard Brodie_1 — Thu, 23 Nov 2006 12:08:59 GMT

"putting in a separate nic, I find, that
this one becomes ewa0

and the onboard ethernet is (suddenly)
we1/ewb0.

Is that always so ?"

It was ever thus. The system scans the hardware and assigns physical device names as it pleases, based on whatever algorithm it uses to scan its peripheral busses. You can absolutely not rely on adding a device of the same preserving the order.

Looking at the PCI addresses in the 255 manual, the top slot and the middle slot have higher/lower addresses compared to the built in Ethernet. You might find swapping the card between the top and middle slots changes the ordering. I'm guessing a bit here but you said you had a scratch system to play with.

Do *NOT* use the bottom PCI slot: bad things will happen.