From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
Big endian, I use htons() to prepare the length for network transmission.
Big-endian, for a DEC-only protocol?! Heresy!
John Wilson
D Bit
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of John Wilson
Sent: 13 December 2012 19:30
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] VCF-East on HECnet?
From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
No. It uses a TCP connection. Each buffer received from the device
driver is sent along on the TCP connection with a 2-byte length prefix,
and that is it. So no DDCMP underneath.
OK cool. Little-endian?
Big endian, I use htons() to prepare the length for network transmission.
[Paul Koning]
If you want to really make your head spin, imagine DMP/DMV emulation
(DDCMP multipoint).
I've never really understood this. Is it a broadcast net, or what?
I'm pretty sure I have a pair of DMVs in this mess somewhere...
John Wilson
D Bit
It is being merged into the official SIMH builds by Mark Pizzolato, I am
hoping it will be in the next release. I just checked with Mark and he is
not ready to share the code quite yet, but there should be some almost
official code to share soon.
Regards
Rob
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of Paul_Koning at Dell.com
Sent: 13 December 2012 15:20
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] VCF-East on HECnet?
On Dec 12, 2012, at 5:32 PM, Rob Jarratt wrote:
...
If you want to peer with me using DMC11 let me know. I will need to
know your IP/DNS address and a port you want to listen on. You can
download a Windows executable of the VAX780 emulation with DMC11
support here:
http://sdrv.ms/Lmg33s I am hoping that the DMC11 will be in the next
release of SIMH, and perhaps in the PDP11 emulation too.
I'd be interested in trying that. The Unibus emulation should just carry
over.
Is the source available?
paul
On Dec 13, 2012, at 2:29 PM, John Wilson wrote:
From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
No. It uses a TCP connection. Each buffer received from the device driver is
sent along on the TCP connection with a 2-byte length prefix, and that is
it. So no DDCMP underneath.
OK cool. Little-endian?
[Paul Koning]
If you want to really make your head spin, imagine DMP/DMV emulation
(DDCMP multipoint).
I've never really understood this. Is it a broadcast net, or what?
I'm pretty sure I have a pair of DMVs in this mess somewhere...
For the gory details, read the DDCMP spec. It's gory, all right.
Physically is's a broadcast net. Logically there is a single master and N-1 slaves. The master polls each of the slaves. The master can send at any time; the slave can send only in response to a poll. I think in theory it can be full duplex, I'm not sure if in practice that made any real difference.
Performance sucks, but if you needed lots of connected stations without using up lots of hardware on the PDP11 side, multipoint is an answer. Ethernet, of course, is vastly superior, but that came later.
It could be worse. I once spent some weeks debugging a communication problem between a PDP11 and some Harris 2200 terminals. Those used multipoint also, but Bisync, not DDCMP. And the interface was a DL11-E. So: half duplex bisync multipoint over a 9600 baud async line. I think it needed the -E variant because the modem control signals were used for poll control. Yikes.
paul
From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
No. It uses a TCP connection. Each buffer received from the device driver is
sent along on the TCP connection with a 2-byte length prefix, and that is
it. So no DDCMP underneath.
OK cool. Little-endian?
[Paul Koning]
If you want to really make your head spin, imagine DMP/DMV emulation
(DDCMP multipoint).
I've never really understood this. Is it a broadcast net, or what?
I'm pretty sure I have a pair of DMVs in this mess somewhere...
John Wilson
D Bit
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On Behalf Of Paul_Koning at Dell.com
Sent: 13 December 2012 19:03
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] VCF-East on HECnet?
On Dec 13, 2012, at 1:58 PM, John Wilson wrote:
From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
If you want to peer with me using DMC11 let me know. I will need to
know your IP/DNS address and a port you want to listen on. You can
download a Windows executable of the VAX780 emulation with DMC11
support here:
http://sdrv.ms/Lmg33s I am hoping that the DMC11 will be in the next
release of SIMH, and perhaps in the PDP11 emulation too. To configure
your side you need the following commands:
So, does the DMC11 emulation just send DDCMP messages in UDP
datagrams, or is it more complicated than that?
No. It uses a TCP connection. Each buffer received from the device driver is
sent along on the TCP connection with a 2-byte length prefix, and that is
it. So no DDCMP underneath.
I've been meaning to add DMC/DMR emulation to Ersatz-11 for centuries,
and obviously I'd want to make sure it interoperates with SIMH.
(There are already undocumented ASSIGN/DEASSIGN/SET/SHOW XM:
commands
since ages ago, but the resulting device doesn't actually work.)
Thanks,
John Wilson
D Bit
If you want to really make your head spin, imagine DMP/DMV emulation
(DDCMP multipoint).
I am hoping to add this one day.
Regards
Rob
On Dec 13, 2012, at 1:58 PM, John Wilson wrote:
From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
If you want to peer with me using DMC11 let me know. I will need to know
your IP/DNS address and a port you want to listen on. You can download a
Windows executable of the VAX780 emulation with DMC11 support here:
http://sdrv.ms/Lmg33s I am hoping that the DMC11 will be in the next release
of SIMH, and perhaps in the PDP11 emulation too. To configure your side you
need the following commands:
So, does the DMC11 emulation just send DDCMP messages in UDP datagrams,
or is it more complicated than that?
I've been meaning to add DMC/DMR emulation to Ersatz-11 for centuries, and
obviously I'd want to make sure it interoperates with SIMH. (There are
already undocumented ASSIGN/DEASSIGN/SET/SHOW XM: commands since ages ago,
but the resulting device doesn't actually work.)
Thanks,
John Wilson
D Bit
If you want to really make your head spin, imagine DMP/DMV emulation (DDCMP multipoint).
:-)
paul
From: "Rob Jarratt" <robert.jarratt at ntlworld.com>
If you want to peer with me using DMC11 let me know. I will need to know
your IP/DNS address and a port you want to listen on. You can download a
Windows executable of the VAX780 emulation with DMC11 support here:
http://sdrv.ms/Lmg33s I am hoping that the DMC11 will be in the next release
of SIMH, and perhaps in the PDP11 emulation too. To configure your side you
need the following commands:
So, does the DMC11 emulation just send DDCMP messages in UDP datagrams,
or is it more complicated than that?
I've been meaning to add DMC/DMR emulation to Ersatz-11 for centuries, and
obviously I'd want to make sure it interoperates with SIMH. (There are
already undocumented ASSIGN/DEASSIGN/SET/SHOW XM: commands since ages ago,
but the resulting device doesn't actually work.)
Thanks,
John Wilson
D Bit
Hi,
to all who are interested in trying the new DMC11 network device within the simh prototype (available from Rob, see his mail), here is a short instruction how to configure it under DECnet/VAX:
DECnet/VAX Setup for DMC11s
If you haven't set up DECnet using netconfig.com yet, so do it now.
The netconfig.com command procedure will recognize and set up your DMC11(s) automatically.
Otherwise (DECnet already configured, e.g for Ethernet), do:
$! ==================================================================
$! Setup for two DMC11s, DMC-0 and DMC-1
$! ==================================================================
$ RUN SYS$SYSTEM:NCP
SET EXECUTOR STATE SHUT
DEFINE LINE DMC-0 STATE ON
DEFINE CIRCUIT DMC-0 STATE ON COST 5
DEFINE LINE DMC-1 STATE ON
DEFINE CIRCUIT DMC-1 STATE ON COST 5
$!
$ @SYS$SYSTEM:STARTNET
$!
That's all!
When everything's o.k. (including your network partner's DMC11) the following command should show the line state "on" a while after DECnet has been started:
$ MC NCP SHOW KNOWN LINES
Known Line Volatile Summary as of 4-NOV-2012 11:22:33
Line State
DMC-0 on
NCP>
More or less unwanted states:
DMC-0 on -starting
means: still trying to connect to the other side ..., should be gone after a maximum of 30 seconds, otherwise there is a problem
DMC-0 on -synchronizing
shows up when the other side has been connected, but is not synchronized yet, usually doesn't last longer than a second or two
To get rid of one or more DMC11s, just do:
$! ==================================================================
$! Removal of e.g. second DMC11 DMC-1
$! ==================================================================
$ RUN SYS$SYSTEM:NCP
SET CIRCUIT DMC-1 STATE OFF
PURGE CIRCUIT DMC-1 ALL
CLEAR CIRCUIT DMC-1 ALL
SET LINE DMC-1 STATE OFF
PURGE LINE DMC-1 ALL
CLEAR LINE DMC-1 ALL
$!
Hope this helps - if not, ask for more!
Regards,
Ulli
---
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On Dec 12, 2012, at 5:32 PM, Rob Jarratt wrote:
...
If you want to peer with me using DMC11 let me know. I will need to know
your IP/DNS address and a port you want to listen on. You can download a
Windows executable of the VAX780 emulation with DMC11 support here:
http://sdrv.ms/Lmg33s I am hoping that the DMC11 will be in the next release
of SIMH, and perhaps in the PDP11 emulation too.
I'd be interested in trying that. The Unibus emulation should just carry over. Is the source available?
paul
