Path: utzoo!mnetor!uunet!seismo!sundc!hqda-ai!yendor!fujiirm
From: fujiirm@yendor.UUCP (Roger Fujii)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DSZ downloads
Message-ID: <683@yendor.UUCP>
Date: 20 Apr 88 21:39:00 GMT
References: <8036@iuvax.cs.indiana.edu>
Organization: Applied Computing Technology, Reston, VA
Lines: 34

From article <8036@iuvax.cs.indiana.edu>, by bobmon@iuvax.cs.indiana.edu (RAMontante):
> boneill@hawk.ulowell.edu (SoftXc Coordinator) writes:
> .> 

> .> on my PC running at 2400 baud, and I download a binary file, I get many CRC
> .> fail errors, some timeout errors, and bad data errors every 8K or so. This
> .> tends to slow down the progress of the download, especially when enough
> .> errors arise to cause it to switch to 256 byte packets. Sometimes it even
> .> aborts the download.
> 
> much less any transfer.  I know little about the Sytek cable (Sytek is a
> brand name), but I do know that it thinks it's 8-bit and it processes some
> characters including ctrl-S and ctrl-Q.  I'm kind of impressed that dsz got

This is most of the problem.  The best that I can figure, the reason why you
die at about 8K or so is because the host overruns the sytek's internal
buffer.  A good way to stop making it bomb is to set zmodem's output buffer
to 2-4k.  This prevents the 8K problem.  If you are unfortunate, then you
have additional problems with the mux.  The above is correct.  The sytek
can be configured to nuke the 8th bit and process LOCALLY an XOFF
sent to it (This is really great if the HOST sends the mux an xoff....
this effectively locks the line until you hang up because the host
is waiting for an XON/char, but the SYTEK will NOT pass any characters
back to the host unless the host sends it a XON.  Can you say deadlock?)
Anyway, I hacked up a zmodem so that the crc/block numbers wouldn't
send 8-bit stuff (it's gross.  Translates crc/block # to ascii HEX).  
--
Roger Fujii - ACT, Reston, VA			Phone:		(703)471-9433
Internet: fujiirm@cml.rpi.edu
UUCP: ..!{mimsy,sundc}!{prometheus,hqda-ai}!yendor!fujiirm
-- 
Roger Fujii - ACT, Reston, VA			Phone:		(703)471-9433
Internet: fujiirm@cml.rpi.edu
UUCP: ..!{mimsy,sundc}!{prometheus,hqda-ai}!yendor!fujiirm