[HECnet] Tops-20 ANONYMOUS FAL Preliminary Testing Results/DAP Query

[John Forecast]

> On Dec 24, 2019, at 8:56 PM, Paul Koning <paulkoning at comcast.net> wrote:
> 
> 
> 
>> On Dec 24, 2019, at 11:59 AM, John Forecast <john at forecast.name <mailto:john at forecast.name>> wrote:
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>> 
>> 
>>> On Dec 23, 2019, at 5:51 PM, Johnny Billquist <bqt at softjar.se <mailto:bqt at softjar.se>> wrote:
>>> 
>>> On 2019-12-23 20:24, John Forecast wrote:
>>>>> ...
>>>> That was implemented on RTS-8 and looks like a Phase I implementation - all hand-crafted PAL code. The floppies are available on the net and includes full source code. When I joined the DECnet development group in early 1977, there were a couple of PDP-8 developers as part of the group. I don’t know if they were developing a Phase II implementation but they disappeared after about 6 months - not surprising given the difficulties we were having getting it to fit in a 28KW PDP-11.
>>> 
>>> Poul took a look at the DECNET-8 sources, and figured it was actually not phase I (I thought it was phase I as well). Poul thinks it's close to, if not actually phase II. There are things in there that apparently did not exist in phase I.
>>> 
>> Yes, I agree. I just took a look at the code and the early dates match when Phase I was available (I was using it around the middle of 1976) and the later dates (mid-1977) would have been when we were finalizing the DECnet-RSX Phase II system architecture. The code claims to support NSP version 2.2 but I have no way to map that to a particular phase, only that version 1.0 was dated July 1975 and version 3.1 (Phase III) was dated March 1978.
> 
> A while ago I found a Phase I RTS-8 document that describes the protocol in reasonable detail.  It's clear that Phase I has only a vague resemblance to the later protocols.  For example, the NSP protocol is there, but it's seriously different.  For example, it offers both a connection service and a datagram service.  And various other things work entirely differently than the later versions.  So while Phase III and IV can talk to Phase II NSP with no real trouble, there is no way for any of them to make sense out of what a Phase I node is saying.
> 
> If you have source code, it should be pretty obvious if it's Phase I or Phase II from looking at the NSP packet formats.
> 
I’ve never seen a Phase I protocol spec but DECnet/8 was probably closer to Phase I than Phase II although the dates in the source code appear to cover both phases. Even after Phase II development started the protocols were still being updated - datagram service was still in the NSP spec in early 1977 but was dropped about half way through the development cycle. One advantage we had for DECnet-RSX development (11M/11S/11D and IAS) was that they all shared common protocol processing code, which had been written for an earlier advanced development project, so protocol changes were relatively easy to make.

   John.

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