From: jsm2r@poe.acc.Virginia.EDU (John S. Mitchell)
Subject: Forwarded: Supra V.32bis (Disappointment)
Summary: Mail received from badbunny@gnh-starport.cts.com
Organization: University of Virginia
Distribution: usa
Date: Mon, 13 Apr 1992 23:38:40 GMT

The author of the following mail requested that
I post it to the net for him.

BEGIN Mail from badbunny@gnh-starport.cts.com === CUT HERE ===

Look, my Apple IIGS (2.8MHz, 8 bit data bus, 16 bit internal data bus, 24 bit
external addressing) can keep up with 57,600 bps.  Surely your Mac IIsi can.
We both use the EXACT SAME serial port chip (the SCC) which has a top asynch
speed of 57,600 and the exact same pinout as the Mac SE.  If I can download
'the-wave.txt' using Ymodem-G at v.32bis/v.42bis, so can you.
 
Things that were required for me.
 
#1)  TURN OFF APPLETALK!!!  I know this can be traumatic (I've got an
appletalk network in my room - 2 Apple IIGSs and an AppleTalk IWII), but I
use my modem much more than Appletalk - its easier just to leave it off most
of the time for me.   Appletalk takes a big chuck of time when it generates
an interrupt.  Lots of time to lose characters.  This may not be a problem
for a Mac IIsi (68030 at 16+ MHz?) but it was for me, even at 10MHz/64k cache
(yeah, all I/O goes at 1MHz on any II <bleah>).
 
#2)  Use a HW handshaking cable.  You're already doing that.
 
#3)  Use telecom software written in assembly for speed which supports HW
handshaking.  The software that I use is called ProTERM 3.0 (InSync) - it, of
course, uses the text screen (which Macs don't have) so scrolling at high
speeds isn't a problem.  That doesn't help you since you have a Macintosh.
Ask around on comp.sys.mac to find the most well written Mac telcom software.
I have a feeling the Macintosh communications toolbox (or whatever the
way-cool drop in module comminications manager is called) might have too much
overhead to run at 57,600.  The software has to support accessing the SCC
directly and has to have way fast interrupt driven internal buffering so that
while your Mac is spending gobs of processor time redrawing graphics windows,
you aren't losing data.
 
Needless to say - faster processors make for sloppier programming.  Its
probably likely that the software that comes with the Supra isn't really the
best in the world.
 
Slightly humorous note:  Its kinda nice having a computer that is considered
archaic.  I got a ZyXEL U-1496E at the recommendations of comp.dcom.modems
people.  I love it.  It came with the Zfax software - you know, the one that
was distributed with the MICH virus?  Good thing I don't have a PC.  :)
<grin>
No one writes viruses for the II/IIGS anymore (and NO thats not an
invitation).
 
I'm just talking off the toppa my head here, but I think this is pretty
common sense info.
I'd appreciate it if you'd post this to comp.dcom.modems for me if you think
its of general enuff interest.  Since I don't 'really' have an INET account,
I can read news fine, but can't post directly (unless someone gives me the
address of the specific group <hint, hint>).
 
Thanks and good luck,
Brendan


Late note:  Realize that I wrote this all up before noticing I was replying to
something about 6 days old - I hope by the time you get this that everything
is already worked out.

See ya on the nets...

Brendan Gallagher Hoar -=- badbunny@gnh-starport.cts.com  (INET -> Apple //)
1641 Mt. Eagle Pl.  Alexandria, VA 22302  (703) 998-5687/8657/8032
Newsgroups: comp.dcom.modems