[net.lan] Help! Ethernet configuration

steve@tellab3.UUCP (Steve Harpster) (07/27/84)

I've been trying to get our Ethernet up for a couple months now and I'm
running out of ideas. It seems to come up and go down on its own. Even
rebooting has no effect. I suspect now I may have something configured
incorrectly which would be no surprise --- I only have half of the
documentation for the controller and I'm impatiently waiting for more
to trickle in.

Anyway, we're running several VAX 750's with the Interlan Ethernet 
controller. Each 750 also has 2 DH/DM's and a DZ-11. My question is
where does the Ethernet controller go in the list of floating interrupt
vector devices? My interrupt vectors currently look something like this:

	dm0	320
	dm1	330
	il0	340
	dh0	360
	dh1	400
	dz0	420

Does il0 belong AFTER the dh's? Before the dm's? I moved it there after
the dz and Unix couldn't find it at boot time. It came set at 340 so I
left it there and configured things around it.

A skillion thanks to any help.
-- 
...ihnp4!tellab1!steve
Steve Harpster
Tellabs, Inc.

steveg@hammer.UUCP (Steve Glaser) (07/28/84)

	I seem to recall the CHAOSNET people telling us that
	the interlan boards belong at the very last unibus
	vector.  I'm still not sure why you would want to
	give them the lowest position in the priority scheme...
	seems to me they should go at the second to the highest position,
	just after your uda50's, and other big-time cards.

	Possibly this will help?

Come on now.  Vector assignment has absolutely nothing to do with
priority.  DMA priority is strictly determined by bus position.  The
only thing that matters on vector assignment is that they not be
overlapping.  [At least on 4.1 and 4.2 where they probe the unibus
space during boot causing interrupts to figure out what's where.]

Thus, the only reason for configuring vectors following any particular
scheme is that it makes it easier to run other systems which aren't as
bright about finding things (say VMS and/or diagnostics).

As for the rationale for putting the Interlans at the end of the bus,
that's easy.  Ethernet protocols already deal with lost/damaged packets
by retransmitting so if you get a data late on a recieve, you can
safely ignore the packet.  Actually on the Interlan card, I don't think
you'll ever get these - you just may miss a few NEW packets due to
buffer space limits on the card.

We have a number of large machines (mostly 780s, some 750s) with lots
of Interlan cards, terminal interfaces (DZ and VMZ), tape drives, etc.
We even had to hack the tm11 driver to deal with more than 4 tape
drives and the dmf32 (aka VMZ) driver to not waste interrupt vector
space.

	Steve Glaser, Tektronix
	steveg.tektronix@csnet-relay.csnet	CSNET/ARPANET
	tektronix!steveg			UUCP

dmmartindale@watcgl.UUCP (Dave Martindale) (07/31/84)

If a UNIBUS device appears not to interrupt when it is set for one
interrupt address but does work at others, then in the first case
the interrupt is almost certainly going though a vector that
the uba configuration routines have already reserved for another
device.

Berkeley UNIX, at least, doesn't give a damn where the
device registers or interrupt vectors are, as long as they don't overlap
and the vectors are in the standard range (0-0777, I think).  So pick
anything that is convenient.

If you want to run VMS on the machine for any reason, you may have to
use standard addresses and vectors.