FWIW, those of us working on DECnet were familiar with Malamud's work and would, when feeling very charitable, describe it as "mediocre".
Part of it are probably reasonably accurate. On the other hand, if you can find the books DEC published on the subject, you'd get material that's far more accurate and far better written.
paul
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of Pinocchio
Sent: Thursday, December 29, 2011 4:05 PM
To: hecnet at Update.UU.SE
Subject: [HECnet] Found free good DECnet books
Hi all!
Recently, while searching for good DNA and DECnet source (besides ODL) I found two wonderful books freely and completely available to anyone via Google Books:
1) McGraw-Hill 1989, Malamud, DEC networks and architectures
http://books.google.com/books?id=0CciAQAAIAAJ&printsec=frontcover&hl=uk
2) VNR 1991, Malamud, Analyzing DECnet OSI phase V
http://books.google.com/books?id=fPJSAAAAMAAJ&printsec=frontcover&hl=uk
Johnny,
I entirely agree with you. I do understand serial signalling, however, I have zero experience with DDCMP. I know it was one of the first pipelined protocols, had the ability to piggyback additional data with ACKs and such as well as error correction capabilities that were not very common at the time of the development completion. I understand entirely that the speeds will be very slow, and I was expecting 1200bps and 2400bps, because that was the technology available at the time is deployed in the field. Once I feel I have a good understanding of the protocol, I will likely move on to ethernet (although I have far more experience there), simply because I will step into the decnet plus arena.
Perhaps it seems more complex that I am making it, but I don't learn from reading as much as I do from using and troubleshooting.
Kevin
> Date: Tue, 3 Jan 2012 04:36:12 +0100
> From: bqt at softjar.se
> To: hecnet at Update.UU.SE
> Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
>
> Kevin, what you are basically talking about here then is how do diagnose
> and debug a broken serial connection. It's the same no matter if you are
> running SLIP, PPP or DDCMP on that serial link. It's still just a cable
> with GND, RX and TX, and possibly some modem control signals.
>
> And it is no different if you instead are doing interactive traffic,
> such as a normal terminal connected to a computer. It's still the same
> serial connection.
>
> If you want to understand how a serial port works, that is excellent.
> But the first thing you need to understand is to differentiate between
> the physical layer, and the communications protocol that runs on top of
> that physical layer.
>
> As for PPP or SLIP on VAX/VMS, no, that did not exist earlier than
> DECnet over serial, as VAX/VMS had DECnet before it had TCP/IP, and SLIP
> can only talk TCP/IP. PPP can in theory run any protocol, but it was
> still not implemented on VAXen for DECnet.
> But my point was that if you want to tunnel DDCMP, it will be exactly
> the same solution you'd do if you wanted to tunnel any protocol using a
> serial interface. There are absolutely no difference from your tunnel
> point of view whatever protocol is used on the link.
> It will only be a stream of bytes on a serial link anyway.
>
> And yes, it will work just fine running DDCMP on top, and you can get
> DECnet connectivity that way. However, it is not very fun, since the
> actual speed of the serial interface will be 9600 bps no matter what, if
> you have physical machines involved, since DECnet insists on setting the
> speed of DDCMP interfaces to that, or slower.
>
> Johnny
>
> On 2012-01-03 04.02, Kevin Reynolds wrote:
> > Johnny,
> >
> > First and foremost, I want to learn how to configure and understand how
> > these devices connected historically so I can troubleshoot the
> > connectivity. This gives me the best feeling of true understanding.
> > Unfortunately, I don't have a slew of these systems (I have a single
> > Microvax II) that I can use to interconnect, so I am locked into
> > simulating at least one end of the connection. I was hoping to do this
> > with simh. Secondly, I was hoping to create error conditions and
> > determine whether I can diagnose the problem.
> >
> > As this is legacy hardware, protocols, and otherwise, I understand that
> > aside from understanding how some of our modern protocols and systems
> > emerged from knowledge of the old systems. I am I really hoping to start
> > a little further back to solidify my understanding of modern technology
> > without all of the additional layers of distraction included with modern
> > systems.
> >
> > Did the VAX/VMS platform have an option to include PPP or SLIP previous
> > to decnet +? I have a good knowledge of these protocols. I used slip
> > back in the day when I had to connect with a pr1mos system that wouldn't
> > allow pass-through connection to the internet. PPP, especially multilink
> > using PPP I have implemented multiple times (even recently...silly, but
> > I didn't choose). My ultimate goal is to pass decnet phase IV (not plus)
> > traffic over the connection.
> >
> > Thanks,
> > Kevin
> >
> > > Date: Mon, 2 Jan 2012 11:15:34 +0100
> > > From: bqt at softjar.se
> > > To: hecnet at Update.UU.SE
> > > Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
> > >
> > > The biggest issue I don't understand here is why.
> > > If you tunnel a serial port, you tunnel a serial port. DDCMP is totally
> > > invisible to you.
> > >
> > > You will not learn, or need to understand anything about DDCMP for this.
> > > A serial port sends bytes. You pass those bytes one. Everyone is happy.
> > >
> > > What kind of protocol is implemented, using those bytes, are very
> > > invisible and irrelevant to the tunnel, just as it is to a cable.
> > >
> > > You might as well tunnel SLIP, or PPP. It will work just the same.
> > > They are all just implementing a network layer on top of a serial
> > > connection.
> > >
> > > What are you really trying to accomplish?
> > >
> > > Johnny
> > >
> > > On 2012-01-01 01.57, The Presence wrote:
> > > > Bob,
> > > >
> > > > I really am wanting to use DDCMP for learning purposes. I want to build
> > > > a decnet phase IV network with DDCMP, however, I want to also have the
> > > > ability to pass traffic through to connect to additional nodes that are
> > > > net connected.
> > > >
> > > > Kevin
> > > >
> > > >
> > ------------------------------------------------------------------------
> > > > To: hecnet at Update.UU.SE
> > > > Date: Sat, 31 Dec 2011 16:41:02 -0800
> > > > Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
> > > > From: bob at jfcl.com
> > > >
> > > >
> > > > What is it that you actually want to connect? For the most part, a
> > > > Multinet link simulates the "user experience" of a DDCMP connection
> > > > tunneled over IP. Multinet is a point-to-point DECnet circuit which,
> > > > except for the device names, is functionally identical to any DDCMP
> > link.
> > > > The only reason I can see for using a real DDCMP serial connection
> > > > (either sync or async) would be to connect a machine that didn't
> > support
> > > > an Ethernet interface.
> > > > Bob
> > > >
> > >
>
Kevin, what you are basically talking about here then is how do diagnose and debug a broken serial connection. It's the same no matter if you are running SLIP, PPP or DDCMP on that serial link. It's still just a cable with GND, RX and TX, and possibly some modem control signals.
And it is no different if you instead are doing interactive traffic, such as a normal terminal connected to a computer. It's still the same serial connection.
If you want to understand how a serial port works, that is excellent. But the first thing you need to understand is to differentiate between the physical layer, and the communications protocol that runs on top of that physical layer.
As for PPP or SLIP on VAX/VMS, no, that did not exist earlier than DECnet over serial, as VAX/VMS had DECnet before it had TCP/IP, and SLIP can only talk TCP/IP. PPP can in theory run any protocol, but it was still not implemented on VAXen for DECnet.
But my point was that if you want to tunnel DDCMP, it will be exactly the same solution you'd do if you wanted to tunnel any protocol using a serial interface. There are absolutely no difference from your tunnel point of view whatever protocol is used on the link.
It will only be a stream of bytes on a serial link anyway.
And yes, it will work just fine running DDCMP on top, and you can get DECnet connectivity that way. However, it is not very fun, since the actual speed of the serial interface will be 9600 bps no matter what, if you have physical machines involved, since DECnet insists on setting the speed of DDCMP interfaces to that, or slower.
Johnny
On 2012-01-03 04.02, Kevin Reynolds wrote:
Johnny,
First and foremost, I want to learn how to configure and understand how
these devices connected historically so I can troubleshoot the
connectivity. This gives me the best feeling of true understanding.
Unfortunately, I don't have a slew of these systems (I have a single
Microvax II) that I can use to interconnect, so I am locked into
simulating at least one end of the connection. I was hoping to do this
with simh. Secondly, I was hoping to create error conditions and
determine whether I can diagnose the problem.
As this is legacy hardware, protocols, and otherwise, I understand that
aside from understanding how some of our modern protocols and systems
emerged from knowledge of the old systems. I am I really hoping to start
a little further back to solidify my understanding of modern technology
without all of the additional layers of distraction included with modern
systems.
Did the VAX/VMS platform have an option to include PPP or SLIP previous
to decnet +? I have a good knowledge of these protocols. I used slip
back in the day when I had to connect with a pr1mos system that wouldn't
allow pass-through connection to the internet. PPP, especially multilink
using PPP I have implemented multiple times (even recently...silly, but
I didn't choose). My ultimate goal is to pass decnet phase IV (not plus)
traffic over the connection.
Thanks,
Kevin
> Date: Mon, 2 Jan 2012 11:15:34 +0100
> From: bqt at softjar.se
> To: hecnet at Update.UU.SE
> Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
>
> The biggest issue I don't understand here is why.
> If you tunnel a serial port, you tunnel a serial port. DDCMP is totally
> invisible to you.
>
> You will not learn, or need to understand anything about DDCMP for this.
> A serial port sends bytes. You pass those bytes one. Everyone is happy.
>
> What kind of protocol is implemented, using those bytes, are very
> invisible and irrelevant to the tunnel, just as it is to a cable.
>
> You might as well tunnel SLIP, or PPP. It will work just the same.
> They are all just implementing a network layer on top of a serial
> connection.
>
> What are you really trying to accomplish?
>
> Johnny
>
> On 2012-01-01 01.57, The Presence wrote:
> > Bob,
> >
> > I really am wanting to use DDCMP for learning purposes. I want to build
> > a decnet phase IV network with DDCMP, however, I want to also have the
> > ability to pass traffic through to connect to additional nodes that are
> > net connected.
> >
> > Kevin
> >
> >
------------------------------------------------------------------------
> > To: hecnet at Update.UU.SE
> > Date: Sat, 31 Dec 2011 16:41:02 -0800
> > Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
> > From: bob at jfcl.com
> >
> >
> > What is it that you actually want to connect? For the most part, a
> > Multinet link simulates the "user experience" of a DDCMP connection
> > tunneled over IP. Multinet is a point-to-point DECnet circuit which,
> > except for the device names, is functionally identical to any DDCMP
link.
> > The only reason I can see for using a real DDCMP serial connection
> > (either sync or async) would be to connect a machine that didn't
support
> > an Ethernet interface.
> > Bob
> >
>
Johnny,
First and foremost, I want to learn how to configure and understand how these devices connected historically so I can troubleshoot the connectivity. This gives me the best feeling of true understanding. Unfortunately, I don't have a slew of these systems (I have a single Microvax II) that I can use to interconnect, so I am locked into simulating at least one end of the connection. I was hoping to do this with simh. Secondly, I was hoping to create error conditions and determine whether I can diagnose the problem.
As this is legacy hardware, protocols, and otherwise, I understand that aside from understanding how some of our modern protocols and systems emerged from knowledge of the old systems. I am I really hoping to start a little further back to solidify my understanding of modern technology without all of the additional layers of distraction included with modern systems.
Did the VAX/VMS platform have an option to include PPP or SLIP previous to decnet +? I have a good knowledge of these protocols. I used slip back in the day when I had to connect with a pr1mos system that wouldn't allow pass-through connection to the internet. PPP, especially multilink using PPP I have implemented multiple times (even recently...silly, but I didn't choose). My ultimate goal is to pass decnet phase IV (not plus) traffic over the connection.
Thanks,
Kevin
> Date: Mon, 2 Jan 2012 11:15:34 +0100
> From: bqt at softjar.se
> To: hecnet at Update.UU.SE
> Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
>
> The biggest issue I don't understand here is why.
> If you tunnel a serial port, you tunnel a serial port. DDCMP is totally
> invisible to you.
>
> You will not learn, or need to understand anything about DDCMP for this.
> A serial port sends bytes. You pass those bytes one. Everyone is happy.
>
> What kind of protocol is implemented, using those bytes, are very
> invisible and irrelevant to the tunnel, just as it is to a cable.
>
> You might as well tunnel SLIP, or PPP. It will work just the same.
> They are all just implementing a network layer on top of a serial
> connection.
>
> What are you really trying to accomplish?
>
> Johnny
>
> On 2012-01-01 01.57, The Presence wrote:
> > Bob,
> >
> > I really am wanting to use DDCMP for learning purposes. I want to build
> > a decnet phase IV network with DDCMP, however, I want to also have the
> > ability to pass traffic through to connect to additional nodes that are
> > net connected.
> >
> > Kevin
> >
> > ------------------------------------------------------------------------
> > To: hecnet at Update.UU.SE
> > Date: Sat, 31 Dec 2011 16:41:02 -0800
> > Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
> > From: bob at jfcl.com
> >
> >
> > What is it that you actually want to connect? For the most part, a
> > Multinet link simulates the "user experience" of a DDCMP connection
> > tunneled over IP. Multinet is a point-to-point DECnet circuit which,
> > except for the device names, is functionally identical to any DDCMP link.
> > The only reason I can see for using a real DDCMP serial connection
> > (either sync or async) would be to connect a machine that didn't support
> > an Ethernet interface.
> > Bob
> >
>
The biggest issue I don't understand here is why.
If you tunnel a serial port, you tunnel a serial port. DDCMP is totally invisible to you.
You will not learn, or need to understand anything about DDCMP for this. A serial port sends bytes. You pass those bytes one. Everyone is happy.
What kind of protocol is implemented, using those bytes, are very invisible and irrelevant to the tunnel, just as it is to a cable.
You might as well tunnel SLIP, or PPP. It will work just the same.
They are all just implementing a network layer on top of a serial connection.
What are you really trying to accomplish?
Johnny
On 2012-01-01 01.57, The Presence wrote:
Bob,
I really am wanting to use DDCMP for learning purposes. I want to build
a decnet phase IV network with DDCMP, however, I want to also have the
ability to pass traffic through to connect to additional nodes that are
net connected.
Kevin
------------------------------------------------------------------------
To: hecnet at Update.UU.SE
Date: Sat, 31 Dec 2011 16:41:02 -0800
Subject: Re: SV: RE: [HECnet] Hecnet and DDCMP
From: bob at jfcl.com
What is it that you actually want to connect? For the most part, a
Multinet link simulates the "user experience" of a DDCMP connection
tunneled over IP. Multinet is a point-to-point DECnet circuit which,
except for the device names, is functionally identical to any DDCMP link.
The only reason I can see for using a real DDCMP serial connection
(either sync or async) would be to connect a machine that didn't support
an Ethernet interface.
Bob
Rob,
If it is passing all bits from the serial port over, it should work. My understanding is that serial was solely DDCMP, at least during the VMS days.
Reviewing the simh archives from 2005 I noticed a reference to ipcom (windows package for connecting a physical rs232 port to a network port, allowing serial login from a remote machine), but this won't work for me, as I need DDCMP, not a console connection, not to mention I'm hoping to physically connect a VMS system in the big picture, not simulations. Perhaps there is some configuration to make this happen, I may test the windows/simh setup just to see.
Mark, the toolset will probably work for your purposes.
http://members.lycos.co.uk/ipcom/
Kevin
Date: Sun, 1 Jan 2012 09:23:33 +0100
Subject: Re: [HECnet] Hecnet and DDCMP
From: robert.jarratt at ntlworld.com
To: hecnet at update.uu.se
Working with a friend, I have written a SIMH emulation of the DMC11 device, so you can do this with SIMH. It tunnels the bytes sent to/from the device over a socket. We have used the SIMH emulation to connect my friend to HECnet over a (simulated) DMC11.
The bit I am not entirely sure about is to what extent this is using DDCMP as I don't have a full understanding of DDCMP.
Regards
Rob
On 31 December 2011 18:46, The Presence <tpresence at hotmail.com> wrote:
Hey guys,
Has anyone worked out a mechanism to connect a node to hecnet using DDCMP? Perhaps some tunneling technology over IP, or virtualized serial?
Kevin
Jarratt, did you make this publicly available on the SIMH list? It
would be great to have a DMC11 device emulated, since I insist on
running RSTS/E v8 (for historical reasons... it was the last real RSTS
before "the pollution"). RSTS/E v8 doesn't have ethernet support, so
the only way I could have DECnet is via a (previously unemulated)
DMC11 interface. Does yours work well?
-Mark
On Sun, Jan 1, 2012 at 3:23 AM, Jarratt RMA <robert.jarratt at ntlworld.com> wrote:
Working with a friend, I have written a SIMH emulation of the DMC11 device,
so you can do this with SIMH. It tunnels the bytes sent to/from the device
over a socket. We have used the SIMH emulation to connect my friend to
HECnet over a (simulated) DMC11.
The bit I am not entirely sure about is to what extent this is using DDCMP
as I don't have a full understanding of DDCMP.
Regards
Rob
On 31 December 2011 18:46, The Presence <tpresence at hotmail.com> wrote:
Hey guys,
Has anyone worked out a mechanism to connect a node to hecnet using DDCMP?
Perhaps some tunneling technology over IP, or virtualized serial?
Kevin
The entire HECnet community now lives in 2012 which, considering the radio silence, must have been an impressive occasion for you all :-)
A Happy and Healthy New Year for all of you.
Hans
Working with a friend, I have written a SIMH emulation of the DMC11 device, so you can do this with SIMH. It tunnels the bytes sent to/from the device over a socket. We have used the SIMH emulation to connect my friend to HECnet over a (simulated) DMC11.
The bit I am not entirely sure about is to what extent this is using DDCMP as I don't have a full understanding of DDCMP.
Regards
Rob
On 31 December 2011 18:46, The Presence <tpresence at hotmail.com> wrote:
Hey guys,
Has anyone worked out a mechanism to connect a node to hecnet using DDCMP? Perhaps some tunneling technology over IP, or virtualized serial?
Kevin
