Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!unmvax!uokmax!d.cs.okstate.edu!unx2.ucc.okstate.edu!minich
From: minich@unx2.ucc.okstate.edu (Robert Minich)
Newsgroups: comp.sys.mac.hardware
Subject: Re: Mac+ terminal emulation speeds
Message-ID: <1991Mar24.091155.26577@unx2.ucc.okstate.edu>
Date: 24 Mar 91 09:11:55 GMT
References: <1991Mar22.155813.11505@rcf.rsmas.miami.edu>
Organization: Oklahoma State University Computer Center
Lines: 52

by miller@rcf.rsmas.miami.edu:
|As a followup to the Mac+ accelerator thread, I posted an article regarding
|the speed of terminal emulators (e.g., Versaterm Pro) and whether or not they
|would run faster on an accelerated Mac+. I stated that my Mac+ running
|Versaterm was much slower than a "real" terminal connected to the same line.
|After further (more careful) comparisons, I see that this is not true.
| 
|I have listed a file containing 500 80-character lines from a mainframe to the
|Mac+'s screen and to a couple of terminals. Herewith is the data:
|TERMINAL                                       CHARACTERS/SECOND
|DEC VT240                                            460
|Human Designs HDS3200                                889
|MAC+ with Versaterm emulating a DEC VT220            615

As far as scrolling speed, I have found that people here often perceive
terminals that use jump scrolling as being faster than the same term
with smooth scroll on, even though I've found that at the typical
2400bps rate here there is no difference except for very short line
(approximately 20 characters or less.) I can actually read the stuff on
my screen (when I'm stuck away from my Mac on a dumb term) but others 
have to do ^S and ^Q flow control...

|So, there are two surprises here. First, the Mac+/Versaterm VT220 is *faster*
|than DEC's VT240 which is only about half as fast as a third party terminal.
|Second, all 3 are much slower than I would have guessed....
| 
|How many characters per second should my nominal 19.2k baud connection yield?
| 
|P.S. The numbers shown above remain the same regardless of whether I am
|doing the listing directly from the DEC VAX to which I am connected via
|a LAT server or whether i am doing the listing from a DEC ULTRIX machine
|across an ethernet.

Some things you might try to test effects on transfer rates:
1) resize the window to a be short vertically
2) time an ascii file capture (assuming you can choose to NOT have the
   data echoed to the screen)

I have a for-all-intents-and-purposes-but-not-really direct serial line
that is 9600bps and I DO get text rates of ~950cps if the screens are
dense or I minimize the scrolling that occurs by applying #1 above.
  If you find that scrolling is slowing down your term emulator, then
an accelerator should help out. I find my SE/30 significantly better
at keeping up with scrolling than SEs and Pluses, although all Macs do
just fine on the serial ports for the data rates in question. Ideally,
a graphics coprocessor would do all the work, but then Apple would have
to change their philosophy on the Macintosh architecture. 
-- 
|_    /| | Robert Minich            |
|\'o.O'  | Oklahoma State University| "I'm not discouraging others from using
|=(___)= | minich@d.cs.okstate.edu  |  their power of the pen, but mine will
|   U    | - "Ackphtth"             |  continue to do the crossword."  M. Ho