Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!uunet!mcsun!cernvax!jmg
From: jmg@cernvax.UUCP (john gerard)
Newsgroups: comp.unix.ultrix
Subject: Re: TN3270 on DS3100 working
Keywords: TN3270, DS3100, Pmax, compiling, ftp
Message-ID: <1130@cernvax.UUCP>
Date: 30 Oct 89 12:56:57 GMT
References: <9149@batcomputer.tn.cornell.edu>
Reply-To: jmg@cernvax.UUCP (john gerard)
Organization: CERN European Laboratory for Particle Physics, CH-1211 Geneva, Switzerland
Lines: 40

In article <9149@batcomputer.tn.cornell.edu> hurf@tcgould.tn.cornell.edu (Hurf Sheldon) writes:
>
>There was some interest in this from all corners of the globe...

Not surprised. My only surprise was that it didn't work anyway.

Actually, here I have taken an alternative path, which is to hack the
3270 (not TN3270) source, with the object of providing a LAT to 3270
gateway for terminals on DECservers, to be run on DS3100s (when the disks
arrive). One thing led to another, so I finished up doing all sorts of mods.
I think mine is now much more efficient, both in CPU usage and in minimising
the number of characters sent to the ASCII terminal. The original curses
refresh routine was ABYSMAL when the new screen was similar to the old
screen, with many unnecessary escape sequences: I originally rewrote the
curses refresh routine but then decided that curses was too limited anyway,
especially because of its generality and the limitation of 8 bits per
character on the screen. I still use the low-level termcap routines (with
extensions). Of course, I have lost the multi-window aspect of curses, but
my users on a simple ASCII terminal won't care.

Extra facilities that I found useful were inclusion of a 3270 status
line, automatic checking of terminal screen size and occasional intelligent
use of blinking mode. There is also a graphics possibility, whereby the
IBM program starts to put out transparent mode characters to drive a
display such as Tektronix 401x or 410x.

 I would be interested to hear from any other 3270 "hackers". I would be
especially interested in anyone who knows how to handle colour on colour
terminals (or PCs with terminal emulation, since we can then telnet from
them to the DS3100 and run the emulator). I hear about ANSI colour sequences,
but all that I have found are simple sequences to change foreground and
background colours, not the colour of individual characters. As for how
to get colour on a VT340...!

Mike Gerard
-- 
 _ _  o |             __                    |    jmg@cernvax.uucp
| | |   |     _      /  \  _   __  _   __  _|    jmg@cernvax.bitnet
| | | | |_)  /_)     |  __/_) | (___\ | (_/ |  J. M. Gerard, Div. DD, CERN,
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