Re: setting up a LAT service via a terminal server

From: Hans Vlems (hvlems.nieuw_at_zonnet.nl)
Date: 08/25/03 

Date: Mon, 25 Aug 2003 14:07:58 +0200

"Phillip Helbig---remove CLOTHES to reply" <helbig@astro.multiCLOTHESvax.de>
schreef in bericht news:bi7sj9$3la$1@online.de...
> Apart from the consoles, I have a VT320 connected to a serial port of a
> node in my hobbyist cluster. If that node is down for some reason,
> however, then of course one can't log in via that terminal. (The
> terminal in question is in my son's bedroom. How many 9-year-olds do
> you know who know how to use EDT? One of my biggest triumphs was when I
> heard him say "Mama's PC doesn't have a PROPER keyboard"!) Thus, I
> would like to have the terminal connect to the CLUSTER instead of to a
> specific node.

:-)

>
> It seems the way to do this would be to connect via a terminal server.
> I have a DECserver 250 and a DECserver 200/MC. Presumably these will
> work fine for what I want to do. I also have the necessary cables etc.
>
> Unfortunately, this stuff is located 500 km from where I spend most of
> my time, so I don't have much time to experiment. What I need is a
> step-by-step guide to setting up what I need. Presumably, the LAT
> service has to be created somehow, perhaps the terminal server has to
> boot from somewhere etc.
>

I have no knowledge of the DS250, it was IIRC intended to connect
lineprinters to ethernet.
A DS200 gets its microcode from a load host. The DS200 uses PR0801ENG.SYS,
the DS100 uses PS0801ENG.SYS. I can email them to you, they're small.
They reside in SYS$SYSROOT:[MOM$SYSTEM], the logical name that points to
that is MOM$LOAD.
Żou can put the download incantations in NCP, like:

$ mc ncp sho node astaat char
Node Volatile Characteristics as of 25-AUG-2003 13:31:15
Remote node = 1.8 (ASTAAT)

Service circuit = EWA-0
Hardware address = 08-00-2B-06-3A-E8
Load file = MOM$LOAD:PS0801ENG.SYS

The decserver 100 has a DECnet address only to put the data in the ncp
database. DECnet is not used, only MOP in the communications. Note that the
circuit (here EWA-0) must have its service cicuit enabled:

$ mc ncp sho circ ewa-0 char

Circuit Volatile Characteristics as of 25-AUG-2003 13:33:21

Circuit = EWA-0

State = on
Service = enabled
Designated router = 1.39 (KALIUM)
Cost = 4

When the DS200 runs, you can use NCP to connect to the server: $ mc ncp
connect node astaat

You get the 3 prompt in return. Type the password ACCESS to get in.
Once in you must make yourself a privileged user:

Local> set priv
SYSTEM

If the DS200 was in use somewhere then it may have different values. you can
reset the DS200 to factory settings as follows: Make sure the device is
power off. Push the square red button on the back and connect the power
cord. Once the DS200 has booted, let go of the red button.

> I have no experience with LAT other than using SET HOST/LAT to connect
> to other nodes (in the cluster) and no experience with terminal servers
> (except as an end-user).
>
> Ideally, switching on the VT and hitting RETURN would bring up the login
> sequence from some machine in the cluster.

The DS200 uses define and set commands in the same way as NCP does, for
permanent and volatile storage. The DS200 has a pretty comprehensive help
tool built in. HELP DEFINE PORT will give you a pretty good idea what to do.
The ports of the DS200 may be configured one by one or all at the same time:

Local> define port all session limit 1 speed 300
Local> define port 1 speed 9600 type ansi

Port 1 is (by default) the console port. Put a VT on it when you power up
the DS200, it'll tell you what is happening.
The DS200 has only 64 kB memory. Most of it is used to buffer the sessions.
So memory is spent on speed and sessions. If you want to conserve memory,
reduce the session limit to 1 and the speed to 300 baud for all ports. Later
you can set the attributes for the port(s) that you are going to use at
reasonable values, like:

Local> define port 2 type ansi preferred service MYCLUSTER autoconnect
enable

The last command will connect that port to the LAT service MYCLUSTER
automatically.

>
> At the moment, the cluster has a VAX at 7.3, a VAX at 7.2 and an ALPHA
> at 7.2-1. There is no DECnet running. LAT is configured so that one
> can SET HOST/LAT to and from any machine in the cluster. With TCPIP I
> have a cluster alias so that to the outside world, the cluster behaves
> as one machine. Ideally, I'd like the same functionality with LAT.

On each node in the cluster use:

$ mc latcp create service MYCLUSTER

 (In
> fact, since the connection to the outside world is via a DSL
> switch/router which does PAT and forwards incoming connections to the
> cluster alias, not only is there just one address for INcoming
> connections, but just one address for OUTgoing connections as well, the
> external address of the router. (Normally, a cluster alias applies to
> just incoming connections, whereas each node will use its own address
> for outgoing connections.))
>
> Load-balancing would be nice just to get some experience with it, but
> for my purposes failover (like with the TCPIP cluster alias) would be
> enough.
>
> While I'm at it, I have an LNO3 sitting around. Can I connect that to
> the terminal server as well?
>
Yes. You need the LATsymbiont to connect to printers. And create a LAT port
on the VMS system, like:

$ mc latcp
set node/conn=both
set node/service_responder
cre port lta8:/applic/log
set port lta8:/queue/node=astaat/port=port_8/log
exit

I'm sure this is not complete but it should get you going.

Hans