Subject: Re: autoconfiguration question
To: <>
From: Ignatios Souvatzis <>
List: tech-kern
Date: 05/23/1997 11:46:32
Jason Thorpe wrote:

> ...err, why?  If you just handle HDLC in zstty, then you can use
> any line discipline ith it, yes?  Then localtalk is a line discipline
> like ppp...

Don't think so. HDLC is packet-oriented stuff.

You can implement the lower half of HDLC as:

- sync HDLC, which is done by special hardware, or
- async HDLC, which can be implemented (if you insist) as a line discipline
  on a async serial terminal.

You can't implement sync HDLC as a line discipline on top of special
hardware ... because the line discipline interface is (currently)
byte-oriented, and the driver wouldn't be able to signal packet
boundaries to the line discipline. 

Well, if you were pervert enough, you could make the driver recode the
sync HDLC into async HDLC, which the line discipline could transform
back into packets. :-)

The real solution would be, to have some stackable interface which at
least CAN signal packet boundaries (for normal tty applications, they
would just be ignored).