[HECnet] Re: Hecnet addition

[Paul Koning]

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

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.

Johnny> Way fun, and impressive. Thanks for that piece of information
Johnny> and history.   I guess they didn't see much need of DDCMP
Johnny> support in RSTS/E at that point. How did you select which
Johnny> serial port it would use, by the way? Or was this only done
Johnny> for the PRO?   Hmm, I guess it could have been passed in in
Johnny> the syscall...

There is an "assign" syscall (which normally in RSTS means "reserve
this device for me even when it's not open") which binds a ddcmp
driver pseudo-device unit to a tty device unit number, via a syscall
parameter.   So you could have, say, up to 8 ddcmp ports, and those
could be bound at runtime to any of your terminal ports.

          paul