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From: ked@garnet.berkeley.edu (Earl H. Kinmonth)
Newsgroups: comp.dcom.modems
Subject: Re: xyzmodem problems
Message-ID: <24597@agate.BERKELEY.EDU>
Date: 19 May 89 03:41:17 GMT
References: <24404@agate.BERKELEY.EDU> <1399@bucket.UUCP> <765@omen.UUCP> <24552@agate.BERKELEY.EDU> <25165@coherent.com>
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In article <25165@coherent.com> dplatt@coherent.com (Dave Platt) writes:
>In article <24552@agate.BERKELEY.EDU> Earl H. Kinmonth writes:
>
>XMODEM has been implemented on _many_ systems, because it's a simple
>protocol to code up and because the protocol description is in the
>public domain.

This would suggest that the term "brain dead" is best applied to the
people who installed it on the VAX I use - a system without an "honest"
eight-bit path from the outside - without documenting the limitations
of the protocol. Back where I come from, we'd call something like this,
"About as useful as teats on a boar hog!"

>ZMODEM can, at least, deal with situations in which the reverse path
>(receiver-to-transmitter) is not 8-bit-transparent... this covers a
>large percentage of the download-lots-of-data-over-a-network situations.

After my original posting, I was able to get zmodem to work for both
up and down loads.  The trick for uploads was to use

rz -e

to force quoting of all control characters.  I have not run any precise
benchmarks yet, but given my path

ATT6310 (Xenix) <==> 9600 baud line <==> switch <==> Develnet <==> SUN

my IMPRESSION is that (large packet) kermit and zmodem offer similar
performance for ascii files.  For binary files, zmodem seems quite a
bit faster.  As time permits, I'll try to make serious tests.

>running.  My impression is that there was less emphasis laid on its
>ability to permit _uploading_ of data over these same networks;  I could
>very well be wrong.  [Chuck... care to comment, if you're following this
>thread?]

As noted above, rz -e, works fine. The documentation leaves much to be
desired however. I figured out for myself how to run zmodem from kermit
and how to patch Sandy's version of CU to call zmodem. I would say that
I figured this out in spite of the ZMODEM documentation, not because of
it.

Presumably (flame me if I'm wrong as I'm sure you will) the author of
Zmodem is between a rock and a hard place on this: he'd like to have
the protocol become more widespread BUT he'd prefer this happen through
purchase of PRO Yam (a name that rubs me the wrong way) rather than
splicing the protocol into public domain software.

I can supply a version of Sandy Z's CU hacked to properly call zmodem.
Whether this is equivalent to the "seamless integration" promised in
Pro Yam (which has received mixed reviews), I do not know.  At least
it's free.

Earl H. Kinmonth
History Department
University of California, Davis
Davis, California  95616
916-752-1636 (2300-0800 PDT for FAX)
916-752-0776 (secretary)
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