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From: treesh@vangogh.helios.nd.edu
Newsgroups: comp.sys.cbm
Subject: Re: Interfacing a Commodore 64 with a VAX/VMS
Message-ID: <1991Apr9.130813.8840@news.nd.edu>
Date: 9 Apr 91 13:08:13 GMT
References: <S!R_S_+@cs.widener.edu> <1991Apr7.012003.423@vax1.mankato.msus.edu> <2HV_JWD@cs.widener.edu> <11611@jarthur.Claremont.EDU>
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Organization: University of Notre Dame,  Notre Dame
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I can see the flames alredy starting to grow on this Zmodem issue again!
Zmodem would really be great on the 64/128 if it where at all practical,
but dew to the hardware structure of the system and its I/O, timming would
just be too critical, and the over-all speed performance would not be
worth the efforet, and the effort, to say the least would be one hell of
a project for even the best serial hardware programer!
 
Since Swiftlink has come our way, and high baud rates can now be achieved
protocols like Ymodem batch, and Xmodem 1K provide pretty fair trasfer
rates, espically to a REU.  However, there is one protocol that is not
yet supported by the c64/128 systems that I have really grown to love on
the Amiga system, and its a very simply protocol called Y-Modem-G.  This
protocol is only useful on modem with MNP-4 or higher.  The reason is becase
it does not do ANY error checksums, and therefor sends files very fast, and
and complexity of the protocol is not present like in X-modem-CRC.  The reason
this protocol can work at all is because with MNP4 implemented in the 
modem, there will be NO errors in the data.

ctfm