[HECnet] FW: More NRT --> VMS and others

[R. Voorhorst]

From: R. Voorhorst [mailto:R.Voorhorst at swabhawat.com] 
Sent: Tuesday, 05 May, 2020 12:04
To: 'owner-hecnet at Update.UU.SE' <owner-hecnet at Update.UU.SE>
Subject: RE: [HECnet] More NRT --> VMS and others

 

Hi Thomas,

 

I use NRT frequently on the older systems as CTERM does not work well with
them; often bursty IO.

On VAX/VMS, NRT usually works well, at least as host and cooperates well
with Tops10/Tops20 Panda.

Also on Rsx11M and Rsts 10.1.

 

Sethost on Tops20 Panda to VMS however does not:

 

sethost

Escape character(^Y):

Host name: swbv89

 

? Communication with VMS not supported by SETHOST

 

Even on OpenVms alpha 8.3 it works to vax, however with connection to
tops10/20, the process crashes with an exception.

Maybe it could be repaired on Alpha, but I doubt sufficient sources are
around.

 

 

You can test initial connect on Swbv55 on hecnet when it is up, as it is a
VAX VMS 7.3 hecnet area router, though you cannot login on it (yet?).

 

 

Best regards,

 

R.V. 

 

From: owner-hecnet at Update.UU.SE <mailto:owner-hecnet at Update.UU.SE>
[mailto:owner-hecnet at Update.UU.SE] On Behalf Of Thomas DeBellis
Sent: Tuesday, 05 May, 2020 07:14
To: hecnet at Update.UU.SE <mailto:hecnet at Update.UU.SE> 
Subject: [HECnet] More NRT

 

What's fun about the Tops-20 NRT client (SETHOST) is that it doesn't do much
aside from parsing for an escape character and node name.  It builds a
connection string and checks to make sure the remote system is either a 10
or a 20.  Then it twiddles a few things on the terminal (a few more if
you're running my changes to handle page mode).  Finally, and this is the
cool part, it issues an MTOPR% to directly connect the local user's terminal
to the open DECnet connection (port 23).

Thereafter, the client does nothing until the interrupt character is typed
or the connection is broken.  So response can be pretty snappy because you
are never running in user space; no context switching.  The CTERM client on
the other hand is reading and writing data and otherwise handling the
specifics of the protocol in user space.  So, more overhead and more context
switching.

As an experiment, I removed the checks for Tops-10 and Tops-20 and tried
connecting to a few hosts on HECnet.

*	Tops-20; TOMMYT and TWENEX worked (of course)
*	Tops-10; VENTI worked
*	RSX-11+; MIM accepted the connection and broke it as soon as I
started typing.  
*	VMS; LEGATO accepted the connection and broke it as soon as I
started typing.
*	RSTS; TRON accepted the connection and then did nothing.  It never
broke the connection, but never displayed any banner or anything else.  It
appeared hung.

So it would appear that NRT servers only exist on the 36 bit line.  Perhaps
it's possible to configure the service for other platforms?

The first few RSTS systems I tried didn't appear to be online; MEZZO, PLUTO,
RSTSE and BITXOT.  The few Windows systems I checked didn't appear to be
online, either; WXP, MISSY, KIBBEH and WATAN.  I'm not sure if that means
they refused the connection attempt outright.

 

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