From: Eric Backus <ericb AT lsid DOT hp DOT com>
Subject: Re: DVANSI Problem: Demacs arrow keys not same as ANSI.SYS
To: jdk5906 AT tamsun DOT tamu DOT edu
Date: Fri, 23 Apr 93 14:59:45 PDT
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu (djgpp)
Mailer: Elm [revision: 66.25]

Jason Kridner / jdk AT tamu DOT edu writes:
> > >   I own DV/X serial no. xxx-xx-xxxx and have noticed what I
> > > believe to be an incompatibility between ANSI.SYS (MS-DOS 6) and
> > > DVANSI.COM (DV/X 1.0).  When I load DEMACS with ANSI.SYS loaded,
> > > I have no problems with my arrow keys.  The arrow keys do not
> > > operate however when I use DVANSI.COM, before loading DV/X or in
> > > a window.  I asked DEMACS to give me the keys for what it thinks
> > > I am pressing when I pressed up arrow and it told me 'C-@ H'.
> > > This is opposed to 'C-p' for ANSI.SYS.  I can write work-around
> > > lisps to solve the problem, but I would like to know if there is
> > > a more compatible version of DVANSI.COM available for
> > > downloading via Internet or otherwise.

The original DEMACS distribution used keyboard remapping to handle
many of the keys on the IBM PC keyboard.  Keyboard remapping is a
little-used feature of ANSI.SYS.  It's not completely clear from your
.emacs whether you are still using keyboard remapping, but I believe
that you are.

A major clue is that DEMACS reports "C-p" for an up-arrow, which is
not what an IBM PC keyboard normally sends when an up-arrow is hit.

Keyboard remapping is a feature which should in general be frowned
upon.  Many replacements for ANSI.SYS do not provide this, on purpose,
and it wouldn't surprise me if DVANSI.COM does not.  The problem with
keyboard remapping is that simply viewing a suitable-rigged text file
can remap the keys on your keyboard.  This allows the creation of
"ansi-bomb" text files, which unexpectedly remap your keyboard and
cause traumatic effects when you try to use your keyboard after
viewing them.

It is possible to rework the DEMACS files so that keyboard remapping
is not needed.  I have done this, as I am sure many others have.  If I
recall correctly, you have to modify both _emacs in your home
directory, and the lisp/term/ibmpc.el file somewhere else.
--
				Eric Backus
				ericb AT lsid DOT hp DOT com
				(206) 335-2495