[Simh] [HECnet] TOPS-20 V4.1 DECnet

[Johnny Billquist]

Hi.

On 2014-05-02 20:02, simh at swabhawat.com wrote:
Hi guys,

what you propose will not work.

I already connected a Tops20 4.1 with a phase-III Tops10 Pdp10 and even that
will not work.
Tops20-4.1 to a clone does as well as a Pdp10 phase-III to a clone does.
Tim Litt mentioned a while ago that Tops20 4.1 was rather more of a phase-II
then a III; I call it phase-II+ as it appears to have some routing
functionality.
So it will certainly not work with Rsts-E 10.1L and Rsx11MP46 as all these
are phase-IV.

Well, if it truly is Phase II, then yeah, I would not expect it to work. But I was pretty sure it was Phase III, in which case it should work.

Further there is no difference between the functioning of a Rsts-E 10.1 and
a Rsx11MP46 Pdp11 with respect to Dup/Dmc/Ethernet if Rsts-E will support
the Dup/Dmc lines and will route as it is primarily an Ethernet system.

Well, therein lies the problem. RSTS/E simply did not support a bunch of thing that RSX did support.
But yes, assuming the OS support a device, it should work equally well under RSTS/E and RSX.

To make these things work the following has to be done:
1.	Upgrade Tops20-4.1 Decnet to real phase-III, it then will link to a
Pdp10 Tops10 7.02 based phase-III router.
2.	Repair/upgrade the Tops10 7.02 router code so that it will talk to a
phase-IV node.

What is wrong with the Tops-10 DECnet phase III code if it don't interoperate with a phase IV node?

Both things will require Tops monitor programming; the Tops10 7.02 case will
probably be the most simple of the two.
On the physical plane nothing is wrong as the packets do flow; only the
DDCMP communication process will not startup; it hangs around in the startup
phase.

That's sad.
But DDCMP should not be too hard to get working. And RSX support DDCMP both on synchronous and asynchronous serial lines. And both using devices that implement DDCMP, and software implemented DDCMP.

	Johnny



Best regards

Reindert

-----Original Message-----
From: simh-bounces at trailing-edge.com [mailto:simh-bounces at trailing-edge.com]
On Behalf Of Cory Smelosky
Sent: Friday, May 02, 2014 19:31
To: hecnet at Update.UU.SE
Cc: simh at trailing-edge.com
Subject: Re: [Simh] [HECnet] TOPS-20 V4.1 DECnet

On Fri, 2 May 2014, Paul_Koning at Dell.com wrote:


On May 2, 2014, at 12:59 PM, Mark Pizzolato - Info Comm
<Mark at infocomm.com> wrote:

On Friday, May 02, 2014 at 7:36 AM, Paul Koning wrote:
...If you want a RSTS system to connect to your Phase III machine,
you'll want to use a DMC (or DMR/DMP/DMV, they are all roughly
interchangeable).   In a sufficiently recent SIMH, the DMC emulation
speaks real DDCMP so it should talk with a software DDCMP
implementation, such as one that uses a DUP.

The DUP has only been tested talking to the KDP and DMC/DMR on RSX.   If
someone wants to try on RSTS I'd like to know if any issues are found.

I'll see what I can do.   Since a DMC/DMR does DDCMP itself, it shouldn't
matter what OS is talking to it; if you get success with DECnet/RSX, I would
expect it to work with DECnet/E as well.


Or, since it doesn't know sync from async, it will probably talk to
a software DDCMP implementation that uses a terminal interface.

I believe that it should also talk to an OS based DDCMP implementation
which uses Async ports.     If someone is willing to test this, I'll work on
any kinks which may be found which might inhibit this.

I'm trying to make some progress on that (using RSTS V10.1).


Let me know.   I'm interested in using RSTS/E to link TOPS-20/KS.

	paul


--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects

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-- 
Johnny Billquist                                   || "I'm on a bus
                                                                  ||   on a psychedelic trip
email: bqt at softjar.se                         ||   Reading murder books
pdp is alive!                                         ||   tryin' to stay hip" - B. Idol
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