Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!yale!umich!samsung!uunet!motcid!king
From: king@motcid.UUCP (Steven King)
Newsgroups: comp.sys.amiga
Subject: Re: Question about a possible transfer protocol
Message-ID: <5220@orchid3.UUCP>
Date: 12 Nov 90 20:10:46 GMT
References: <45220@eerie.acsu.Buffalo.EDU>
Organization: Motorola Inc. - Cellular Infrastructure Div., Arlington Heights, IL 60004
Lines: 39

In article <45220@eerie.acsu.Buffalo.EDU> v128ll9e@ubvmsd.cc.buffalo.edu writes:
>
>	I was thinking late at night on how I could make a brand new and really
>fast transfer protocol.  This is (I think) a completely new idea.  It occured to
>me that the only way to really speed up a transfer is the have the receiving 
>computer send NO information back to the sending computer.
>	The way that it would work (for error checking) is have the sending
>computer would send a CRC check every 1024 bytes.  The receiving computer would
>independently compute the CRC and compare them, if they are different, then and
>only then would the receiving computer send anything back.
>	My question:  would this speed up transfers?  It seems to me that it
>would have to if you programmed to protocol to take advantage of the
>multitasking ability of the Amiga.  The only problem is getting some poeple
>to adopt the protocol.
>
>-Rich

Excuse me, but did somebody mention Zmodem?  What you've described is
essentially the inner workings of Zmodem.  It *is* faster than other
protocols that regularly acknowledge the packets.  The speedup is especially
noticable over packet-switched networks, less noticable for normal dialups.
Zmodem has been around since before 1986; that's the date of the revision on
the spec sheets I have.  (Chuck Forsberg, Omen Technology Inc., "The ZMODEM
Asynchronous Inter Application File Transfer Protocol", rev051486 Printed
5-16-86)

Multitasking isn't necessary, but it might be handy if you wanted to do
simultaneous bidirectional transfers.  There's a "Bimodem" protocol for IBM
PCs that I think is bidirectional Zmodem.  (Don't quote me on that.) The
closest the Amiga world ever got was with a term program called Diga that
would let you transfer one direction and chat with the other person at the
same time.  Don't think it did bidirectional transfers, though.  (Again,
don't quote me.)

-- 
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Nothing is more conducive to peace of mind than    |        Steven King
not having any opinions at all.                    |     Motorola Cellular
         (Georg Christoph Lichtenberg [1742-1799]) |   ...uunet!motcid!king