19 Nov
2021
19 Nov
'21
5:14 p.m.
Please can you explain your second sentence somewhat? I read: "... the Ddcmp layer
... it does present it as a device ...". I do not perceive the connotation.
Reindert
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of
Johnny Billquist
Sent: Friday, 19 November, 2021 14:46
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] ANF10 network --> DN200 (RJE, Decnet) --> should be Ddcmp
--> Re:4
RSX definitely can use a DUP11 standalone through DECnet. In which case it's software
side DDCMP.
Heck, you can also use the DDCMP layer yourself, without involving DECnet. It does present
it as a device to the system on which you can send/receive packets.
Johnny
On 2021-11-19 12:22, R. Voorhorst wrote:
Well, that leaves 0,01% chance to see that assumption
defeated so why not test it?
I'll see next week if that can be tested if a software testbed can be found to
support the single Dup11 that wise: VMS at least does not in the Decnet corner but Vax Psi
may be different. Maybe Rsx-11M+ would be a suitable testbed?
Reindert
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On
Behalf Of Mark Pizzolato - Info Comm
Sent: Friday, 19 November, 2021 05:19
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] ANF10 network --> DN200 (RJE, Decnet) --> should
be Ddcmp --Re3
I have not followed the details of this conversation, BUT I'm 99.99% sure that a
PDP11 can be configured with just a DUP with DECnet using that interface, and that DUP can
be "wired" to another simulator which has a DUP, KDP/DUP or a DMC and DECnet can
be spoken just fine.
- Mark
On Thursday, November 18, 2021 at 3:35 PM, Reindert wrote:
--
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
No, the Dup is only simulated as Kdp/Dup combo, hence the Ddcmp
characteristics of the pair.
Reindert
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner- hecnet at Update.UU.SE]
On Behalf Of Johnny Billquist
Sent: Friday, 19 November, 2021 00:31
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] ANF10 network --> DN200 (RJE, Decnet) -->
should be Ddcmp --Re2
Fair enough.
But DUP11 is a sync character based interface. So that one too
requires that you do DDCMP in software. But I didn't think simh simulated a DUP11?
Johnny
On 2021-11-18 23:33, R. Voorhorst wrote:
--
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
Yes, but they are async lines and these are
indeed character based
with
software determining the protocol, not so the sync liness. Async
decnet ddcmp behaves slightly differently from sync decnet ddcmp in
number of characters used. Look at the packet contents in used
characters and in between.
Reindert
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-
hecnet at Update.UU.SE] On
Behalf Of Johnny Billquist
Sent: Thursday, 18 November, 2021 23:23
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] ANF10 network --> DN200 (RJE, Decnet) -->
should be Ddcmp --Re
Well... RSX for example can talk DDCMP over DZ11 or DL11 lines just
as well,
which are plain simple serial lines existing in simh.
Hopefully such lines can be connected with
interfaces doing DDCMP in
hardware (simulated in simh of course), and it should all
work.
And any software running in RSX just have an interface that gives
the
DDCMP packet layer. The actual serial lines are not accessible as
such by any other software than the DDCMP driver.
Johnny
On 2021-11-18 23:01, R. Voorhorst wrote:
> Point in this case is that the ddcmp is handled in Simh and not in
> system
software so software can only deal with packets/messages; there is
need for a simh sync line where the software itself will be able to
communicate in bytes/characters and synthesize the packets/messages
as the next higher organization.
>
> Reindert
>
> -----Original Message-----
> From: owner-hecnet at Update.UU.SE [mailto:owner-
hecnet at Update.UU.SE] On
> Behalf Of Johnny Billquist
> Sent: Thursday, 18 November, 2021 22:39
> To: hecnet at Update.UU.SE
> Subject: Re: [HECnet] ANF10 network --> DN200 (RJE, Decnet) -->
> should be Ddcmp
>
> Well, a serial line over which DDCMP is running is purely a packet
> based
interface.
>
> Johnny
>
> On 2021-11-18 21:46, R. Voorhorst wrote:
>> Indeed it is Ddcmp, but the meaning is the difference between
>> packet/message oriented and character oriented and the latter
>> should
also exist.
>>
>> Reindert
>>
>> -----Original Message-----
>> From: owner-hecnet at Update.UU.SE [mailto:owner-
hecnet at Update.UU.SE]
> On
Behalf Of Robert Armstrong
> Sent: Thursday, 18 November, 2021 21:11
> To: hecnet at Update.UU.SE
> Subject: RE: [HECnet] ANF10 network --> DN200 (RJE, Decnet)
>
>> Paul Koning <paulkoning at comcast.net> wrote:
>> They speak DDCMP, yes, but not DECnet. Any protocol layered over
>> DDCMP
> should work.
>
> Indeed, and we just proved that with ANF10 which uses the
> DMCs and DUPs but is not DECnet.
>
> Bob
>
>
>
19 Nov
19 Nov
5:22 p.m.
I assume it means that RSX (and RSTS too) lets you use a DMC directly from an application
as an I/O device you can open. If so, you get a packet service that lets you transmit
whatever packets you want, which will be sent encapsulated in DDCMP protocol. In the RSX
case I'd assume that includes support for maintenance mode (in RSTS that isn't
supported).
paul
On Nov 19, 2021, at 11:14 AM, R. Voorhorst
<R.Voorhorst at swabhawat.com> wrote:
Please can you explain your second sentence somewhat? I read: "... the Ddcmp layer
... it does present it as a device ...". I do not perceive the connotation.
Reindert
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of
Johnny Billquist
Sent: Friday, 19 November, 2021 14:46
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] ANF10 network --> DN200 (RJE, Decnet) --> should be Ddcmp
--> Re:4
RSX definitely can use a DUP11 standalone through DECnet. In which case it's software
side DDCMP.
Heck, you can also use the DDCMP layer yourself, without involving DECnet. It does
present it as a device to the system on which you can send/receive packets.
Johnny
5:50 p.m.
Well, I meant this in the context of a DUP11, but sure, it's also true
with DMC.
But basically, in RSX, DECnet is just a component of something called
the communications executive, or CEX. CEX provides its own environment
in which multiple processes run, and provide services.
CEX then provides an interface to its drivers from RSX, which means that
any RSX program can make use of the services and protocols that CEX
have, without have DECnet in the picture.
So for example, CEX provides communication lines, which are packet
based. If that is over asynch lines it utlizes DDCMP over async serial.
Any application in RSX can make use of this. If you instead have a synch
line, like a DUP11, or DMC, that is another interface inside CEX. From
the outside it makes no difference if it is a DUP or a DMC. Bottom side
is synch serial, using DDCMP. With DMC this is all done in the hardware.
With a DUP11, CEX is doing the DDCMP layer in software.
For the user program this is all invisible. You just communicate over
the DUP11, and it will be doing DDCMP.
If you actually want to use the DUP11 *whithout* DDCMP, then you'd go
for the DUP11 device driver instead of accessing it through CEX.
And talking to a device using CEX in RSX means you talk to the "direct
line access" interface, or DLX. That is just one interface, independent
of what underlying hardware you are going to access. In the DLX, you
start by opening the link, and for that you use the name, which is the
same as the line name you see for DECnet. But you are in fact then just
talking at the line level, using whatever protocol layer is used for
that line. DDCMP, for example.
Anything using DDCMP is always in packets. Don't matter how the hardware
looks.
DLX is also used to access ethernet, by the way. And that is how I
coexist with DECnet in RSX, since ethernet can allow multiple channels
on the same hardware.
I hope this makes sense. Else I can try to explain it more.
Johnny
On 2021-11-19 17:22, Paul Koning wrote:
I assume it means that RSX (and RSTS too) lets you use
a DMC directly from an application as an I/O device you can open. If so, you get a packet
service that lets you transmit whatever packets you want, which will be sent encapsulated
in DDCMP protocol. In the RSX case I'd assume that includes support for maintenance
mode (in RSTS that isn't supported).
paul
--
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
On Nov 19, 2021, at 11:14 AM, R. Voorhorst
<R.Voorhorst at swabhawat.com> wrote:
Please can you explain your second sentence somewhat? I read: "... the Ddcmp layer
... it does present it as a device ...". I do not perceive the connotation.
Reindert
-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of
Johnny Billquist
Sent: Friday, 19 November, 2021 14:46
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] ANF10 network --> DN200 (RJE, Decnet) --> should be Ddcmp
--> Re:4
RSX definitely can use a DUP11 standalone through DECnet. In which case it's software
side DDCMP.
Heck, you can also use the DDCMP layer yourself, without involving DECnet. It does
present it as a device to the system on which you can send/receive packets.
Johnny
7:06 p.m.
All,
This discussion has been quite interesting! Back in the 1982, I did programming for a
large RSX11M/DECnet based system that input commodity trading data from around eight
different commodity exchanges (CBOT, COMEX, Mercantile, etc.) as well as commodity news
service and distributed it to over 200 VT100s located all over the U.S.
The host system was an 11/44 connected to the development 11/44 via DMCs and
they shared a DT07 bus with box. In the DT07 was a couple DZ11s for data input
from the exchanges and a DV11 with 16 synchronous serial ports that were connected
to twelve remotely located 11/23s running RSX11S & DECnet.
The 11/23s were downloaded RSX11S via their DUV11s and the re-entrant RSX tasks
received DECnet task to task data packets about trades and then displayed individualized
data to ~20 VT100s on DZV11s and DLV11-Js.
A DUP11 on one of the 11/44s also did RJE jobs to an IBM mainframe. A watch-dog
timer ran between the 11/44s so that a semi-hot fail over could occur and the DT07 would
move the I/O to the development system if the primary had hardware issues.
Later I had an 11/24 that connected into this network via the CPUs 2nd DL11 port that
was often used for a TU58. I don?t remember exactly what it connected to on the 11/44
side. All the network connections were 9600 baud point to point lease lines from
AT&T.
If anyone out there has a DECnet distribution for RSX11S, I?d love to get a copy
to experiment with today.
Best,
Mark
On Nov 19, 2021, at 10:50 AM, Johnny Billquist <bqt
at softjar.se> wrote:
Well, I meant this in the context of a DUP11, but sure, it's also true with DMC.
But basically, in RSX, DECnet is just a component of something called the communications
executive, or CEX. CEX provides its own environment in which multiple processes run, and
provide services.
CEX then provides an interface to its drivers from RSX, which means that any RSX program
can make use of the services and protocols that CEX have, without have DECnet in the
picture.
So for example, CEX provides communication lines, which are packet based. If that is over
asynch lines it utlizes DDCMP over async serial. Any application in RSX can make use of
this. If you instead have a synch line, like a DUP11, or DMC, that is another interface
inside CEX. From the outside it makes no difference if it is a DUP or a DMC. Bottom side
is synch serial, using DDCMP. With DMC this is all done in the hardware. With a DUP11, CEX
is doing the DDCMP layer in software.
For the user program this is all invisible. You just communicate over the DUP11, and it
will be doing DDCMP.
If you actually want to use the DUP11 *whithout* DDCMP, then you'd go for the DUP11
device driver instead of accessing it through CEX.
And talking to a device using CEX in RSX means you talk to the "direct line
access" interface, or DLX. That is just one interface, independent of what underlying
hardware you are going to access. In the DLX, you start by opening the link, and for that
you use the name, which is the same as the line name you see for DECnet. But you are in
fact then just talking at the line level, using whatever protocol layer is used for that
line. DDCMP, for example.
Anything using DDCMP is always in packets. Don't matter how the hardware looks.
DLX is also used to access ethernet, by the way. And that is how I coexist with DECnet in
RSX, since ethernet can allow multiple channels on the same hardware.
I hope this makes sense. Else I can try to explain it more.
Johnny
905
days inactive
905
days old
3 comments
4 participants
participants (4)
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bqt＠softjar.se -
mark＠matlockfamily.com -
paulkoning＠comcast.net -
R.Voorhorst＠swabhawat.com