"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