Path: utzoo!attcan!uunet!cs.utexas.edu!csd4.csd.uwm.edu!mailrus!ames!haven!decuac!shlump.nac.dec.com!mipsbx.nac.dec.com!thomas
From: thomas@mipsbx.nac.dec.com (Matt Thomas)
Newsgroups: comp.unix.ultrix
Subject: Re: LAT Terminal Server Manager for Ultrix
Keywords: LAT, DECserver
Message-ID: <4212@shlump.nac.dec.com>
Date: 19 Aug 89 17:18:05 GMT
References: <7683@cbmvax.UUCP> <1989Aug16.233014.9741@acd4.UUCP>
Sender: news@shlump.nac.dec.com
Reply-To: thomas@decwrl.dec.com
Organization: Digital Equipment Corporation
Lines: 26

> Of course, the how to do whatever ccr(8) does is something that DEC has
> chosen not to document.  This may not be so horrible, I've been looking
> at what lpd does to dynamically attach LAT connections, and it's gross!

It is gross.  No argument from me (no, I didn't write the code) on that.
But that's one of the reasons lcp -h /dev/ttyxx:server:port was included
in V3.0.  So that the mechanics are taken care of in the kernel.  Hopefully
a better way will come along to do the dynamic attaching that lpd needs.
It might even be done via an ioctl similar to LIOCTTYI.  But then again, maybe not.  

> It's not a simple "lat_atttach" system call, rather there's a bunch of
> procedureal gruk that reflects that fact that LAT is neither TCP nor
> DECnet, rather it's more of a do-it-yourself talk direct to the ethernet
> I/F hack, which, like DECnet, is sort of grafted onto the Unix networking
> while remaining it's own rather perverse view of the world...

Except for the HIC support (which I admit is not very pretty), LAT is very
well integrated into the kernel.  The LAT ttys are real ttys (not ptys which
rlogin/telnet/dlogin use).  LAT talks to the network interfaces just like 
IP or DECnet and talks to the tty code just like a DZ or DHU driver.  Granted
the code has its bugs and warts but it is getting better.
-- 
Matt Thomas                     Internet:   thomas@decwrl.dec.com
DECnet-Ultrix Development       UUCP:       ...!decwrl!thomas
Digital Equipment Corporation   Disclaimer: This message reflects my own
Littleton, MA                               warped views, etc.