Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!purdue!decwrl!shelby!labrea!dudevoir@bernoulli.Stanford.EDU
From: dudevoir@bernoulli.Stanford.EDU (Glen P. Dudevoir)
Newsgroups: comp.sys.mac
Subject: Re: zterm emulation problems
Keywords: vt100
Message-ID: <24@bernoulli.stanford.edu>
Date: 14 Jul 89 20:40:59 GMT
References: <23@bernoulli.stanford.edu>
Sender: dudevoir@bernoulli.Stanford.EDU (Glen P. Dudevoir)
Reply-To: dudevoir@bernoulli.UUCP (Glen P. Dudevoir)
Distribution: na
Organization: Stanford University
Lines: 56

I thought I would post a summary of the responses to my previous
posting because some of them have been via email.

In article <23@bernoulli.stanford.edu> dudevoir@bernoulli.stanford.edu (Glen P. Dudevoir) writes:
>I have tried out both versions 0.75 and 0.8 of Zterm and have found
>some problems in the vt100 emulation. Neither version will handle
>editing in vi or gnuemacs.  0.75 scrolls the entire screen after 
>a cr in the command line (bottom line of terminal) and then fails
>to redraw the screen so the cursor positioning is not correct.

After posting this I realized that this problem also affects 0.8.

Stephen Robinson (robinson%prism@gatech.edu) replies:

I found that I had to increase the
zterm window size to 25x81 (keeping the shell's crt length at 23 or 24)
to get rid of the scroll/fail to redraw problem.

>In version 0.8 moving the cursor to the left in the editors causes the
>characters that it is passing over to be erased from the screen, but
>not from the file being edited.

Dave Platt posted the patch to 0.8 that fixes this problem.
I would also like to point out that the ZTerm 0.8 in the info-mac
archive at SUMEX seems to already have this patch applied.

>One other note: I have had some problems transferring files using the
>zmodem protocol at 19200.  I consistently get errors of the type 
>ZRPOS 0 . At 9600 everything goes well.

Dave Platt replies:
My experiments with a USR Courier HST modem seem to indicate that
19200-bps connections between the modem and my Sun 3/60 are not
reliable.  The Sun appears to drop characters on the floor if they
arrive at high speeds from the modem.  I suspect that the Sun's serial
port isn't fast enough to keep up with sustained input bursts at 19200.
This sort of occasional character-loss would raise merry hell with
ZMODEM handshaking.  I had similar problems connecting the HST to our
Sun 3/260's ALM-2 serial-port expander board... the ALM-2 ports simply
aren't fast enough to keep up with sustained input at 19200 bits/sec.
The only Sun serial ports that I've found to work reliably at this speed
are the two CPU-board ports on the 3/260 server.

I have not had enough time to finish checking this out yet and admit
a lack of knowledge on how these protocols are working exactly, but
I have not noticed any problems before in using the sun 3/60 serial
ports at 19200, most notably using mac xmodem transfers with
Versaterm. In fact, I have even gotten mac xmodem to work at 38400
from versaterm, but I can't remember if I ever tried uploading at this
speed or download (sun to mac) only.

Again, I like ZTerm and think zmodem has a whole lot to offer that 
mac xmodem doesn't. I am not trying to knock this program, just get
the best performance possible from it.

Glen   dudevoir@bernoulli.stanford.edu