[HECnet] DECnet Implementation and Productization of RSX-11M, 11S, 11D and IAS (was Re: Anonymous FAL (Tops-20))

[Johnny Billquist]

As far as I can remember, the DN20 didn't go beyond phase III, but I 
could be wrong.

Also, RSX20F is a sort of bastard RSX. It's something of a mix between 
RSX-11D and RSX-11M, running without an MMU (called an unmapped system 
in RSX speak). It is rather weird. I believe the sources are available. 
I seem to remember reading through them a couple of years ago when I was 
having an argument with Timothy Litt (if I remember right). I had 
earlier thought that it was more purely -11M, and Litt claimed it was 
not at all. He was closer to correct than I was, but it turned out 
RSX20F was a really odd thing.

   Johnny

On 2019-07-14 19:48, Thomas DeBellis wrote:
> I had been wondering about the RSX DECnet packaging.
> 
> 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.
> 
> 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.
> 
> 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.
> 
> 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.
> 
> 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.
> 
> I can't remember whether the DN20 would do anything past Phase III.
> 
>> ------------------------------------------------------------------------
>> On 7/5/2019 7:57 PM, John Forecast wrote:
>> 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.
>>
>> [...] 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.

-- 
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