ttyd0/cuad0 - why is there still this duality ?

[Kurt J. Lidl]

On Mon, Jan 24, 2005 at 04:16:13PM +0100, Bernd Walter wrote:
> On Mon, Jan 24, 2005 at 09:30:43AM +0100, Christoph P. Kukulies wrote:
> > Just a question. Maybe it isn't true but to me it seems there
> > is still this duality between ttyd and cuad serial devices.
> > 
> > Why is that? I'm just asking because someone I was talking with 
> > about modems an comm programs was 'criticising' this fact
> > in FreeBSD "while other systems long have abandoned this dualism"?
> 
> Because modems are still used for dial-in and dial-out.
> tty handing out to getty and cua to the dial out process.
> Moreover this handling was recently added for usb serials under
> -current.
> If other systems loose features - well it's their problem.

That's a very limited way of looking at the functionality.  If you
want to support the functions of both dialin and dialout on one
serial port, there doesn't need to be more than one kernel device.
Just because support for this got hacked into 4.2BSD in a gross
manner doesn't mean that there isn't a better of doing this.

Having seperate dialout and dialin devices really are just a kludge
for having the kernel doing locking that could be done in userland
code.

Just because FreeBSD does this the same way it's been done on
BSD-ish systems for the last 15 years doesn't mean there isn't a
better way of doing it.

-Kurt