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From: barmar@mit-eddie.UUCP (Barry Margolin)
Newsgroups: net.info-terms
Subject: Re: vt100, :am:, :xn:, :in:
Message-ID: <2912@mit-eddie.UUCP>
Date: Thu, 18-Oct-84 01:11:01 EDT
Article-I.D.: mit-eddi.2912
Posted: Thu Oct 18 01:11:01 1984
Date-Received: Sun, 21-Oct-84 10:20:08 EDT
References: <459@uwvax.UUCP> <5084@brl-tgr.ARPA> <194@bragvax.UUCP> <297@ptsfa.UUCP> <5339@brl-tgr.ARPA> <368@umcp-cs.UUCP>
Reply-To: barmar@mit-eddie.UUCP (Barry Margolin)
Organization: MIT, Cambridge, MA
Lines: 25

In article <368@umcp-cs.UUCP> chris@umcp-cs.UUCP (Chris Torek) writes:
>VT100s have neither behaviour.  Instead, after writing in column 80,
>the cursor is in sort of a ``virtual 81st column''.  If you put out a
>backspace, the cursor goes to column 80 (i.e., it doesn't move).  Same
>for ESC[D.  For ESC[C (cursor right) the cursor stays in col. 81.  For
>any printing character, the cursor immediately moves to col. 1 of the
>next line, then you get the printing character (or tab) done, and then
>the cursor moves to col. 2.  For line feeds and up & down motions in
>col. 81, the cursor moves to the next or previous line and col. 80.
>
>In-Real-Life: Chris Torek, Univ of MD Comp Sci (301) 454-7690
>UUCP:	{seismo,allegra,brl-bmd}!umcp-cs!chris
>CSNet:	chris@umcp-cs		ARPA:	chris@maryland

I believe that this is not the case for VT100's, although it would be
nice if it were.  When the cursor is in the "virtual 81st column" it is
displayed in the "physical 80th column".  If you then backspace (and
presumably also when you use the cursor-left escape sequence) you end up
in the 79th column (physical AND virtual).  I also use Honeywell VIP
terminals at work; they do it right (one of the few things that VIPs do
right).
-- 
    Barry Margolin
    ARPA: barmar@MIT-Multics
    UUCP: ..!genrad!mit-eddie!barmar