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From: bigbroth@babcock.cerc.wvu.wvnet.edu (James M. Coleman)
Newsgroups: comp.sys.amiga
Subject: Re: VMS Y & Z MODEM protocols
Message-ID: <481@cerc.wvu.wvnet.edu.edu>
Date: 14 Apr 90 19:24:06 GMT
References: <10263@shlump.nac.dec.com>
Sender: news@cerc.wvu.wvnet.edu
Lines: 34

From article <10263@shlump.nac.dec.com>, by coburn@clo.enet.dec.com (John T. Coburn):
> 
> In article <24071@usc.edu>, papa@pollux.usc.edu (Marco Papa) writes...
> :In article <41676@iuvax.cs.indiana.edu> sl195091@silver.ucs.indiana.edu (Andy Hartman) writes:
> :>Here at IU, we tried to implement Zmodem, but the project was abandoned because
> :>of the fact that the VAX (VMS 4.5 or close :-) ) deals in 7 bits while z modem
> :>is an 8 bit protocol.  If I am wrong, let me know (no flames!!!!) but I think
> :>this is the reason it wouldn't work here.
> : 
> :You're right: ZMODEM requires an 8-bit data path.

> VMS is not limited to 7 bit serial data paths and has never been as far
> back as I remember. The X.25 networks and X.29 PADs may be limited but this is
> not a restriction imposed by VMS. 

I believe the problem in implementing ZMODEM on VMS deals with it's
recoginizing certain 8 bit strings as control sequences and interrupting
the transfer, not in VMS being unable to handle 8 bit data paths. This is
why Kermit uses only printable characters for file transfers and does 
prefixing when transfering binary files. I would think one could find
out what control sequences would be a problem to transfer and write
an 8 bit protocol which transfers these control sequences in a different
format. This would NOT be a portible protocol and is one reason Kermit,
a very portible protocol, is still widely used.

                                              Jim Coleman

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