[HECnet] Re: Hecnet addition

[Paul Koning]

"Johnny" == Johnny Billquist <bqt at softjar.se> writes:

Johnny> Paul Koning wrote:
RSTS does too (for sufficiently recent versions, like V10 or so)
-- though the NCP bits don't seem to be there.   But there's a
driver and it can be told to turn on if you issue the DECnet
control syscalls directly.

Johnny> Aha. I think I looked at RSTS/E DECnet SPD only, and didn't
Johnny> find any mention of it, back when I was playing with that.

That would make sense given that the support isn't complete.

Johnny> I wonder why you can't set it from NCP though? Weird if they
Johnny> have the functionality, but no "normal" way of enabling it.

Probably history.   I created the async DDCMP driver when I was doing
the (unreleased) PRO port for RSTS (9.6 originally).   I handed it to
RSTS development, and they integrated it into the release.   But I
personally never did the NCP work.   Probably because it wasn't
familiar code and it would have been a lot of work.   Instead, I just
wrote a little 10 line utility to issue the line on/off syscalls to
the kernel.

On a Pro it even works in synchronous mode (because there the
"UART" is actually a USART).

Johnny> I don't think you can set it to synch mode in DECnet, though,
Johnny> so that is more of a theoretical thing.   But yes, RSX
Johnny> supports both synch and asynch mode.

What I meant is that I did synch mode, including for DECnet, in RSTS.
It successfully talked to a DMR (both in 4.0 mode and DMC mode -- I
remember digging up the details of the "DMC bugs" that DMC mode on the
later devices is meant to handle).

It was an interesting experience.   The DDCMP spec is so well written
that you can simply implement what it says and it all works.   That's
how it should be, but specs that good are unfortunately quite rare
(and essentially nonexistent in more recent times).

BTW, a DDCMP driver for Linux would be a pretty easy thing to do.   I
started looking into it but didn't have the spare time to do the
actual coding. 

        paul