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<p>Whoops, an IBMSPL communications endpoint was called a DN60, not
a DN20.</p>
<p>None of that stuff ran over an Ethernet, which IBM did not sell,
yet. You had to use KMC11's.<br>
</p>
<div class="moz-cite-prefix">On 7/14/2019 1:48 PM, Thomas DeBellis
wrote:<br>
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<blockquote type="cite"
cite="mid:898ba9d6-c695-c07c-276a-8a54095c2a1c@gmail.com">
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<p>I had been wondering about the RSX DECnet packaging.</p>
<p>Pre-CI DECSYSTEM-20's may be modeled according to a loosely
coupled multi-processor paradigm, with the main KL being
communicated with DTE20's, the master one having additional
rights. These were connected to either a front end
communications processor (which handled the communications, unit
record equipment and I believe the ANF10) and other networking.
These were packaged in separate cabinets as DN20's.</p>
<p>The DN20 subsystems were 11/34 - 11/40 class machines, which
might now be better thought of as ancillary processors or even
embedded systems, but sometimes were running cut down versions
of full blown operating systems. The front end ran a version
of RSX called RSX20F and was somewhat stripped down, not having
a login.</p>
<p>A DN20 was termed a DN20 if it ran the 2780/3780/HASP
communications code that IBMSPL talked to. Since I was Columbia
Galaxy nerd and knew PDP-11 assember, I also maintained that
code (and worked with our VM/MVS folks to fix a pesky bug in the
multi-leaving implementation). As I recall, this was embedded
code and precisely RSX based (but it's been at least 35 years
since I assembled any of that). I think I used a 20 based cross
assembler to do it.<br>
</p>
<p>We did have an RSX20F pack, but I don't recall as I ever looked
at source on that. Or maybe it was on microfiche.</p>
<p>Do you know how DECnet would have been packaged for the DN20
and DN200 (the DECnet based RJE station)? One assumes it would
have been built off of RSX.</p>
<p>I can't remember whether the DN20 would do anything past Phase
III.<br>
</p>
<blockquote type="cite"
cite="mid:F9A42C87-6D5D-48CC-86F0-83CA7A57F425@forecast.name">
<hr width="100%" size="2">On 7/5/2019 7:57 PM, John Forecast
wrote:
<pre class="moz-quote-pre" wrap="">What you see in CEXBF.MAC is all there ever was for CEX. When I joined the development team in Jan ’77, an implementation of Phase II NSP was running standalone under a “Communications Executive”. The decision was made to “port” this “Communications Executive” into each of the RSX-11 Decnet implementation (11M/11S/11D and IAS) and they would all use this NSP implementation. As a side benefit we would get all the device drivers that had been implemented as well.
</pre>
<pre class="moz-quote-pre" wrap="">[...] that would be too expensive if every packet had to flow through NETACP. When a packet is queued to a process (asynchronous rather than direct call) it is queued to the NS: fork block. When NS: driver runs as a result it peeks at the request and may queue it to NETACP or process it immediately.
</pre>
</blockquote>
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