AT&T 630MTG

[Doug Gwyn]

In article <10925 at sol.ARPA> dibble at cs.rochester.edu (Peter C. Dibble) writes:
>Does anyone have an idea where I can get enough information about the
>630's operating system to write code for it?  I bought the Software
>Development Guide and found nothing in there but fluff about C programming
>and utilities.  I don't even know how to _invoke_ the operating system yet!
>I imagine that I could learn enough from the source package but I would
>rather do this without using secret stuff.  I'd like to be able to
>give OS-9 support for the terminal away when I'm done with it.

Unfortunately there really is no substitute for the software development
system source code.  For one thing, it defines all the entry points to
the terminal's firmware.  For another, you need a LOT of support software
to fully exploit the terminal.  I'm rather familiar with the terminal and
its software, but I wouldn't even dream of trying to construct the support
software from scratch.

The protocol "understood" by layers-based terminals while operating in
non-layers mode is described in their manuals.  Basically, they have a
magic ANS X3.64 escape sequence to initiate code downloading for standalone
applications, or the built-in layersys "layers operating system".  AT&T
UNIX System V Release 3 "wtinit" is supposed to be useful for this, but
actually you need more than that to operate in layers mode (also, I'm
not sure that all versions of "wtinit" work right with a 630).  The host
"layers" program takes care of kicking the terminal into layers mode and
providing shell processes on the host when windows are created, among
other similar functions.  

Once started, layersys (actually I think it's called "mpxterm" now)
communicates with the host multiplexor via AT&T's "xt" packet protocol,
which is described in SVR3 manuals.  However, it is really hard to produce
a working version of "layers" just from the documentation, and it is almost
impossible to build downloadable applications to run as processes in the
terminal without using the 630 software development source code from AT&T.
I don't think the support code is very expensive, though, and sublicensing
is probably quite inexpensive.  I haven't checked recently; maybe someone
who has could tell us what it costs.

P.S.  I forgot to mention in an earlier note that there are vendors
other than AT&T and Pyramid from whom you can obtain 630 host support.
Usually you have to specifically ask for it, as it is an add-on product.
Alliant is one such vendor.  Also, Keith Muller's port for 4.3BSD is
advertised as working correctly on several implementations of 4.3BSD
as well as on SunOS (where a bug in the pty handler may have to be fixed
first).  I think the latter is obtainable directly from AT&T Teletype;
perhaps someone there would please enlighten us.