[HECnet] Re: Hecnet addition

[Paul Koning]

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

Johnny> Paul Koning wrote:
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.

Johnny> Way nice. In RSX, you need to reserve the whole controller at
Johnny> netgen, and no ports can be used by anything else than DECnet
Johnny> if you set it up.   DECnet/RSX has its own device driver for
Johnny> the serial port cards.

For RSTS it's a connection from the regular terminal driver to the
DDCMP driver, which acts as a sort of coprocessor.

Linux has the same notion; it's called "line discipline" if I remember
right, and is nicely modular.   That's where DDCMP would go if one were
to do it for Linux.

    paul