Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!ncar!umigw!umiami!tcwan
From: tcwan@umiami.miami.edu
Newsgroups: comp.sys.mac.comm
Subject: ZTerm Uploads (SUMMARY)
Message-ID: <6762.26caa73f@umiami.miami.edu>
Date: 16 Aug 90 18:01:34 GMT
Organization: Univ. of Miami (IR)
Lines: 73

Well, here's the summary for the problems encountered with zmodem
uploads to a Unix/Ultrix host:

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The Problem:

In article <6509.26939a0f@umiami.miami.edu> tcwan@umiami.miami.edu writes:
<>
<>We have the same problem here using a MicroVax running Ultrix 3.0. It'll hang
<>on sending files from ZTerm to the Ultrix host, but downloading from the host
<>has no problems (It's the fastest protocol I've found by far!). The error
<>message is something like "ZRPOS returns zero" and ZTerm will keep retrying.
<>
<>I'm using ZTerm 0.85 and rz 3.00 dated 4-19-89.

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Dave Alverson replies:

There are two things to try.  First, check the "Escape Controls" option
in ZModem Parms.  Some digital switchs or term servers can swallow
some control chars and kill any transfer.  This option will cause
control chars to be sent as a two byte sequence.

Also, try putting a multiple of 512 in the Window Size option in
ZModem Parms.  This puts the protocol into a windowed mode (for
send only).  2048 is a good first guess for this option.

The message "ZRPOS <number>" is just the receiver saying Hey, I got
an error.  Please back up to file location <number>.

Also, note that some Unix box serial drivers may not be able to keep
up with data coming in full bore at 9600 bps.

  -- Dave

-- 
Z  Dave Alverson,   Cincinnati & Mason, Ohio
Z  Address: davea@kgw2.bwi.WEC.COM                                           
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I tried all the above, but none applies, although they might solve some
problems for others. After talking with my sys. admin., I discovered
that the Ultrix box is set to enforce the parity bit on input. 
Output is set to ignore parity, so downloads from the Ultrix host will work.

If you do a "stty everything", there is a parameter "pass8" (at least, in
Ultrix) which should be set. If it shows as "-pass8" this will result in
the "ZRPOS = 0" condition described above. Doing a "stty pass8" to set the
flag does not work as I guess ZTerm resets the parameters on the beginning
of the transfer. The gettytab file needs to be modified to accomplish that,
as far as I know (at least, that's what the sys. admin. did).

Also, I noticed that ZTerm is not too robust whenever the ZRPOS error occurs.
Of all the times I've tried it, it hung up the Mac II so completely that
the on/off switch does not work. I had to pull the power plug to restart
the computer. (System 6.0.4, Finder 6.1.4, quite a few inits)

Someone also emailed me concerning how ZTerm will not upload a file if
the same name is present on the Unix host. This pretty much defeats the
purpose of upload crash recovery of zmodem. (That's how the duplicate name 
problem occurs normally).

If you're trying to get the latest versions of rz/sz, they can be
obtained via anon. ftp from sumex-aim.stanford.edu, as
info-mac/unix/zmodem-part?.shar. The versions I saw there last was sz 3.03
and rz 3.00. Newer versions exist but I'm not sure where to get them.

Well, I hope this answers all the questions. It has been rather frustrating,
but then again, serial connections tend to be that way... :0(

T.C. Wan
Univ. of Miami Computing Facilities
Internet: tcwan@umiami.miami.edu