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From: jpn@teddy.UUCP
Newsgroups: comp.sources.d,comp.terminals
Subject: Re: VT100's keeping up at high baud rates
Message-ID: <4101@teddy.UUCP>
Date: Mon, 15-Jun-87 10:37:39 EDT
Article-I.D.: teddy.4101
Posted: Mon Jun 15 10:37:39 1987
Date-Received: Wed, 17-Jun-87 01:07:39 EDT
References: <1149@carthage.swatsun.UUCP> <8601@tekecs.TEK.COM> <6828@mimsy.UUCP> <1075@laidbak.UUCP> <1119@copper.TEK.COM>
Reply-To: jpn@teddy.UUCP (John P. Nelson)
Organization: GenRad, Inc., Concord, Mass.
Lines: 24
Xref: utgpu comp.sources.d:782 comp.terminals:281

>> - Some (all?) PC/clones cannot keep up with speeds > 4800 baud in the VT100
>> - terminal emulator
>> 
>Heck, even the VT100 "emulation" inside a bona-fide _V_T_1_0_0 can't
>keep up at speeds of more than 4800 baud.
>

I once did some benchmarking that you all might find interesting.  I
wrote a program which did nothing but fill a 80x24 screen with blanks
several times, to time the terminal throughput (admittedly, without
scrolling, since that was not part of our requirement).  The only
escape sequences I used were 'ESC [ H' to home the cursor after
reaching the bottom, and the inverse video character attribute on/off
(toggled after every pass, so you could watch the progress of the
benchmark on the screen).  I wrote an entire screen at a time to
minimize system overhead.  Flow control was enabled to avoid overruns.

Anyway, true VT100's had a throughput just over 9600 baud.  VT101's had
a throughput of only 4800!!!!  VT220's could go a sustained 19200 baud!

Sorry, I don't have the program anymore, but i would be interested to see
similar benchmarks on other terminal types.  Also, I would be
interested in seeing a "scrolling" version of this benchmark.  Any
takers?