Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!jarthur!mti!dave
From: dave@mti.mti.com (Dave Stuit)
Newsgroups: comp.sys.ti
Subject: Re: TELCO problems (was Re: Charter available??)
Keywords: TELCO, terminal emulation, keyboard
Message-ID: <1078@mti.mti.com>
Date: 13 Jul 90 02:08:49 GMT
References: <633@compnect.UUCP> <1990Jun18.134728.4886@ecn.purdue.edu> <1071@mti.mti.com> <697@compnect.UUCP>
Reply-To: dave@mti.UUCP (Dave Stuit)
Organization: Micro Technology, Anaheim, CA
Lines: 54

In article <697@compnect.UUCP> dave@compnect.UUCP (Dave Ratcliffe) writes:
>In article <1071@mti.mti.com>, dave@mti.mti.com (Dave Stuit) writes:
>> [lots of questions and some bitching and whining ;-) ]
> [lost of answers with good info on TELCO, Fasterm, the Geneve, etc.]

Thanks, Dave, for your replies to all my questions.

>>     The problem I had was missing functions.  Perhaps
>>     the biggest omission I found was that none of the emulations supported
>>     the line insert/delete capabilities of the emulated terminals.
>>     [...]
>Again, still a problem even with the Geneve with a full PC style keyboard.

I suspect my original posting was unclear.  Except for a few annoyances
(like the DEL character *not* being the usual FCTN-V, and thus *not*
touch-typable), i don't have problems with the keyboard.  I don't like giant
keyboards with lots of useless function keys, anyway.  And the editors i use
(jove [an emacs variant], vi, etc.) require nothing more than an ASCII
keyboard, which the 4A/TELCO provide.

The missing functions i was referring to are the host-controlled functions
performed by the terminal (i.e., those described in termcap).  Let me
explain with an example.  If i'm using my favorite text editor and i want to
delete a line, i hit ^K twice.  No problem.  The editor gets two ^K's and
the lines are gone, but now it has to update my screen.

If i was using a Wyse 50, the editor would need to send only two
characters:  ESC R.  This would cause the terminal to delete the line where
the cursor was positioned, and move all lower lines up one to fill the space,
leaving the bottom line blank.  The editor knows this, and would then send
the right characters to fill the bottom line on my screen with the next line
of the file.  Thus, no matter where my cursor is when i delete a line, no
more than 100 characters (and sometimes only a few) have to be sent.  The
same goes for other "intelligent" terminals (vt100, tvi925, a210, to name
but a few).

But a "dumb" terminal (e.g., adm3a) isn't capable of doing much more than
putting the cursor where it's told and displaying each character it receives
on the screen.  Thus when my editor wants to update my screen after i delete
a line, the only way to do so is to redraw the entire screen, from the line
i'm on to the bottom.  This could be just a few characters (if i'm on the
bottom line), or almost 2,000 (if i'm at the top).  At low baud rates, this
becomes pretty painful.

Unfortunately, all of the partial emulations provided by TELCO fall into the
dumb-terminal category.  (It's not my intention to be trashing this fairware
product that performs remarkably well considering the limitations of the
video display processor, memory, etc.  I'm just trying to figure out if
there's a reasonable way to do what i'm trying to do.)

--dave
-- 
Dave Stuit		( dave@mti.com  or  uunet!mti!dave )
Micro Technology, 5065 E. Hunter Ave., Anaheim, CA  92807  (714)693-2396