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From: thad@cup.portal.com (Thad P Floryan)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: Full vt100 emulation
Message-ID: <26488@cup.portal.com>
Date: 1 Feb 90 11:34:45 GMT
References: <8711@cbnewsm.ATT.COM> <26393@cup.portal.com>
  <3060@becker.UUCP>
Organization: The Portal System (TM)
Lines: 50

bdb@becker.UUCP (Bruce Becker) in <3060@becker.UUCP> brings up some good
points re: VT100 emulation, termcap/terminfo, etc.

If one calls INTO one's UNIXPC and selects TERM=dt80 (a faster, better VT100
emulation) using a DT80 (or a VT100 :-), everything is fine for the remote
user.

If one wishes to (logically) "cu" OUT from one's system, THEN the need for a
proper VT100 (or whatever) emulation package becomes painfully evident; no
termcap or terminfo will help under this condition.

As I replied to someone else in e-mail, the areas in which most terminal
emulations fail miserably (on any system (3B1, Amiga, Mac, IBM PC, Atari ST,
etc.)) include:

	double-wide and double-wide/-high characters
	VT100 alternate and graphics character sets
	scrolling regions
	video attributes (bold, blink, underline, reverse, etc.)
	80 and 132 column displays
	other "DECPRIVATE" functions

Even expensive commercial products such as Mirror II for the IBM-PC fail
miserably ... they just don't work properly when calling INTO other systems
that insist on a "proper" VT100 emulation.

This is NOT a trivial concern.  A *LOT* of commercial applications REQUIRE
proper emulation.

I didn't realize myself how BAD the problem is until last week when one of
my clients started using an existing application on one of my VAX systems
and NOTHING they could run on their IBM PCs performed properly because of
the poor VT100 emulation (of their PC-based terminal emulators).

So-called "developers" have ASSUMED (there's THAT word again! :-) that VT100
implies ANSI ... that is NOT the case, and that's why the Per Lindberg VT100
Validation Suite (whose availability on UUNET, osu-cis, elsewhere) I posted
recently.  The Per Lindberg suite is a UNIX- or DEC-20 hosted emulation test
package whose use is mandatory if one is using or writing an emulator.

For the record, NO version of PCOMM emulates a VT100, and NO claim was made
by the author that it did.

Contrast that with all the hokey emulators which DO claim "VT100" but don't
perform worth beans when talking to a VT100-based application.

"X", curses and termcap/terminfo notwithstanding, there are a LOT of
applications in the real world requiring proper emulation.

Thad Floryan [ thad@cup.portal.com (OR) ..!sun!portal!cup.portal.com!thad ]