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From: scott@csusac.csus.edu (L. Scott Emmons)
Newsgroups: comp.sys.ibm.pc
Subject: Re: XMODEM,YMODEM,ZMODEM,KERMIT Which is best and why?
Keywords: ZMODEM, KERMIT
Message-ID: <1990Jan2.070518.1822@csusac.csus.edu>
Date: 2 Jan 90 07:05:18 GMT
References: <32428@news.Think.COM> <919@eecea.eece.ksu.edu> <9457@spool.cs.wisc.edu>
Reply-To: scott@csusac.UUCP (L. Scott Emmons)
Organization: California State University, Sacramento
Lines: 28

In article <9457@spool.cs.wisc.edu> thaler@shorty.cs.wisc.edu (Maurice Thaler) writes:
>>ZMODEM -
>>3.  Not as robust as KERMIT.
>> [...]
>Sorry Dwight, I don't buy this one. ZMODEM is very robust. 32bit-crc
>gives your virtually identical files including date and time stamping.
> [...]

I have noticed that ZMODEM fails miserably when attempting transfers through
a buffered environment, as from what I understand ZMODEM requires stricter
timing than KERMIT, XMODEM, YMODEM, et al.  When I am on a clean line, not
running through many boxes (i.e. direct telco line to one of our micro-vaxen)
ZMODEM runs perfectly.  However, when I use it via our AT&T ISN network, which
runs through a PBX, and several other boxes, ZMODEM fails (It gets a timeout
error _EVERY_ 10K or so [where I assume the buffering is a problem
somewhere in our system]), while YMODEM runs perfectly, 0% packet loss.

So my opinion is that ZMODEM is the best protocol in direct CPU-modem-modem-CPU
installations, while other protocols may be preferable in environments where
data will undergo transformation/transportation through several different
devices, especially equipment akin to AT&T's ISN, which is noisy...at least
at our site...

-- 
			L. Scott Emmons
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