[HECnet] Console terminal switch and/or reverse terminal server suggestion?

[Johnny Billquist]

On 2013-05-14 17:07, Bob Armstrong wrote:
Guys    

    Here   s the situation     I   ve got several PDP11s and a couple of PDP8s
and I want them all to be able to share a single console terminal.     I
could just use an old fashioned RS232 switch box, but I was looking for
something better.   For one thing, a    smart    switch that would actually
buffer output from the unselected ports would be nice, and it   d be nice
to be able to change the selected port from the terminal keyboard.
What   d be idea is something like the multi session support that some of
the later VTxxx terminals had, but with multiple physical ports and
without any special host software.   It   d also be nice if I wasn   t
limited to just one physical console but I could use any terminal
anywhere on the network too.

    I thought about using a DECserver in    reverse LAT    for this, but
AFAIK the only way to connect to a DECserver in reverse is from a real
host system, like VMS or RSX.   That means my console terminal would have
to connect to a VAX, log in, and from there connect out again to the
DECserver and the PDP-11 or 8 console port.   Kinda complicated and ugly.

    I don   t think there   s any way to have one terminal server connect
directly to another terminal server w/o a host system in between, at
least not with LAT.     Telnet would be OK, if anybody can recommend a
multi-port telnet terminal server that works in reverse.   It   d be
especially cool if it can telnet to itself     then I could just connect
directly from one port on the server to another.

    Anyway, I was thinking that I can   t be the only collector with a
bunch of computers and room for only one console, so I thought I   d ask
what other people are using.

No. Any DECserver can act both as ingress and egress, without any intermediate system.

What you need to do is to set up a service. Any computer with LAT can set up one or several services. But any terminal server can also setup a service. And with a terminal on a DECserver, you connect to a service. Don't matter who is presenting the service.

Reverse LAT is slightly different, in that you can connect to an outgoing port on a DECserver without using a service, by using reverse LAT. You just tell which DECserver, and which port on that DECserver to connect to.

But you don't need reverse LAT in your case. Connect all console interfaces to ports on a DECserver. Define all ports access as remote, and setup services for all of them, and you're in business.

However, as you note, they will not really buffer anything, so it's not perfect. You'd need something like screen in Unix, with connections to each machine, in order to get buffering and so on working they way you want.

	Johnny