> On Jan 29, 2022, at 7:37 PM, Johnny Billquist <bqt@softjar.se> wrote:
>
> On 2022-01-30 01:04, R. Voorhorst wrote:
>> L.S.
>> With a bit time on hand and the standstill after Paul's initial test from
>> dup to pydecnet which appeared to be successful, I now undertook a test as
>> Mark liked to have it preferably.
>> So I did a fresh netgen on a simple configuration from simple basic install
>> Rsx11MP system for only a Decnet end-node with one single Dup line
>> communicating to a known working Pdp11 Rsx11MP Dmc circuit.
>> I saw no difference from what I reported initially and later with logging,
>> as was to be expected; my complex setup behaves exactly the same in this
>> respect as it does for years in a complex network setup for Rsx and Rsts,
>> and RT11 without network.
>> This is on a Windows-2008R2 server and I suspect Paul did his test on
>> unix/linux , however although it differs,  that should be moot as far as
>> Simh is concerned.
>> There could be another difference though. Paul would probably have taken the
>> default route and used Ddcmp withouth KG11 support: Dup without Kdp is the
>> only sync line to use it, though async Decnet DL/DZ/VH might use it as well.
>> As I prefer the most complex configs possible (any two of a kind where
>> possible as Dec used to have them), I do also employ the KG11, so for Dup
>> support it will be used when configured so in Decnet11MP.
>
> I would suspect Paul did not run with KG11.

Correct, I was not aware it's possible to use it.  The only software I have seen that uses the KG11 is 2780 emulation.

> I agree that the host system shouldn't make a difference.

Not unless it's big endian, in which case getting this stuff to come out right requires some care.

>> On a sim it is not that effective, but in hardware in the past it did make a
>> difference for fast crc computing.
>
> Actually, as the DECnet installation manual mentions, on an 11/44 or 11/70, you probably do not want to use the KG11 even if you have it, as the software computation is faster than the hardware device
> (see page 5-31 of the DECnet-RSX generation and installation manual).

Makes sense.  The KG11 is pretty old; if it was created back in the 11/20 days that would make much more sense, with basic instruction times in the 3-5 microsecond range.

        paul

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