[Simh] Error in DMC11/DMR11 Emulation in RSTS/E 10.1

[Paul Koning]

> On Jan 4, 2016, at 12:34 AM, Christian Gauger-Cosgrove <captainkirk359 at gmail.com> wrote:
> 
> Just an addendum because I think I may not have been too clear:
> 
> On 4 January 2016 at 00:03, Christian Gauger-Cosgrove
> <captainkirk359 at gmail.com> wrote:
>> Also, this might be more my inexperience, but I can't seem to figure
>> out how to get DECnet to "speak" to the other machine.
>> 
> What I mean to say is, I can't seem to figure out a way to get the one
> host to connect to the other, mostly since I don't "know" DECnet that
> well. (I know what TLK and NET do.)
> 
> Trying NET:
> $ net HOUOU::HELLO
> ?Connect Failure - HOUOU is an unknown node.

DECnet (Phase IV and before) doesn't have anything like DNS.  (Phase V does.)  So each system has its own set of node definitions, analogous to /etc/hosts on a Unix system.  That message indicates that HOUOU isn't a defined node name.

You can find the nodes that are defined by "NCP LIST KNOWN NODES".  You can define new entries:
$ ncp define node 7.7 name testme
$ ncp set node 7.7 name testme

"define" puts the name in the permanent database, which is used at startup to initialize the volatile database.  "set" puts the name in the volatile database.  Similarly, "list" reads the permanent, and "show" the volatile database.  The above is for RSTS; details vary slightly among implementations, in particular the notions of volatile and permanent database.

Another possible issue is that the name is defined but not reachable.  An endnode would not know until you try to connect; a routing node does know (at least for in-area nodes).  For example:
$ ncp sho kno node
Known Node Volatile Summary as of 4-JAN-16 10:21:26

Executor Node = 1.43 (SIMH43)

State                      = On
Identification             = DECnet/E V4.1
Active Links               = 0

Remote Node = 1.1 (PYTHON)

State                      = Unreachable

Remote Node = 1.2 (TEST2)

State                      = Unreachable
...

If you ask for "show active nodes" you get only the executor (local node) plus reachable nodes.  "known" means all nodes with a name (defined nodes) and/or reachable nodes (whether with a name or not).

Trying to connect to an unreachable node results in a connect error, for example:

$ net python
?Connect Reject - NSP reason code = 39

or

$ ncp loop node python

?Listener response - Mirror connect failed, Node unreachable
Messages not looped = 1.


	paul