🚀 go-pugleaf

In article <Apr.12.13.47.28.1990.7927@pilot.njin.net> limonce@pilot.njin.net (Tom Limoncelli) writes:
>In article <02373.AA02373@spirit.kref.sub.org> rob@spirit.kref.sub.org (Roland Bless) writes:
|[ The Amiga can't handle high baud rates.]
|
|| He tested it with different Kickstarts, Workbenchs, serial-devices and
|| port-handlers. He thought that it is maybe his A-1000, so we tested it with
|| my AMIGA-2000 (A-2000B Rev4.3, European/PAL-Model, A2058, A2090-ST1096N).
|
|First of all, use AmigaDOS 1.3.  There were improvements to the
|serial.device.  Also, just for completeness, you might want to use
|AmigaDOS 1.3.2 since it's always nice to be running with the latest
|bug-fixes.

Even better: you *SHOULD* run 1.3.2, because that release came with a new 
serial device that fixes a few bugs (that used to crash the Amiga) and 
improves performance somewhat.

|You did a pretty good analysis, but you had one big flaw:
|You used 2 slow terminal programs.  JRcomm is good, but not at high
|speeds.  Platinum Online is a silly little program that is not well
|respected.  Try VT100 2.9A (free) or ATalk-III+ (commercial).

Thanks for the recommendation.  In fact, we had both Courier HSTs and
Trailblazers in early 1989, when we added support for such modems. With
the Courier HST it is imperative to use RTS/CTS handshake (no X-on/X-off).
Make sure that the cable uses the RTS and CTS lines correctly, and you also
might want to play with the input buffer size (A-Talk III accepts your 
Serial Device Preferences). There are two types of problems to consider:
terminal emulations and file transfers.

1. Terminal Emulations 

A Good terminal emulator should be able to keep up with 9600, *WHEN NOT 
SCROLLING*.  If it can't keep up with it, then you bought a lemon :-)
SCROLLING at high speeds is not feasable, unless the emulator bypasses
a lot of software (i.e. it handles only 1 fixed font, for example).

2. File Transfers

There should never be any problem with "half-duplex" transfers like XMODEM
or KERMIT at speeds up to 19,200, since the packets are small and there is
a large turnaround time (due to the acknowledgement).

When using "streaming" mode protocols, such as ZMODEM or YMODEM-g, you MUST
use hardware handshaking, "optimize" the input buffer size and such things.
We were able to use 19.2K or 38.4K Amiga<->Modem speeds, though at 38.4K we
did get some CRC errors, which are the result of "overrruns" on the serial
port.  Note that when I say "you must use RTS/CTS", I mean that your host
also has to be set up to support it, otherwise you'll still get overruns.

|You asked "why do term program permit high baud-rates when they can't
|handle them?"  Well, it's because most aren't tested at high baud
|rates.  Commercial software does get good testing and you'll only see
|the baud rates listed that they can actually do.  (Oops, I should say
|"*good* commercial software gets good testing).  If you notice, 
|VT100 2.9A only lists the tested baud rates.  The next version will
|include 19.2Kbps because I've tested it at that rate.

Agreed.  VT100 2.9A does indeed work with at speeds.  A-Talk III also
includes support for 57.6K, since the serial port works just fine
"SENDING" at those speeds (and higher).  We use it to send files
to 80x86 systems, that can keep up at those speeds on input, since they do
not multitask.  One thing that you might notice on the Amiga at high speeds,
is the fact that the mouse will not move or will jerk when moved.  There
are just not enough cycles available on a stock 68000 Amiga.  The situation
is much better with a 68020 or 68030-based Amiga.

|So, basically the solution is to get better software: (1) get a new
|application and (2) get 1.4.  Sadly, you can only do #1 right now.

Nah. I can do #2, too :-)

-- Marco
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