7 May
2020
7 May
'20
5:25 a.m.
On Tue, May 5, 2020 at 9:34 PM Paul Koning <paulkoning at comcast.net> wrote:
> On May 5, 2020, at 1:14 AM, Thomas DeBellis <tommytimesharing at gmail.com>
wrote:
>
> 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.
Try NI1D, user ID 100,100. I just checked it and TRON, both correctly
answer the
RSTS remote terminal protocol.
TRON is my system! Glad it was useful for something. It has a guest
account also...66,66 to match the one on MIM.
Regards, Tim.