Path: utzoo!attcan!uunet!lll-winken!ames!xanth!ukma!psuvm.bitnet!cunyvm!ndsuvm1!ndsuvax!ncoverby
From: ncoverby@ndsuvax.UUCP (Glen Overby)
Newsgroups: comp.os.minix
Subject: Re: Protocols (was Re: What to do with rs232 on Minix-ST)
Summary: Kermit implimentations are lacking
Message-ID: <2034@ndsuvax.UUCP>
Date: 17 Jan 89 16:50:46 GMT
References: <1853@ast.cs.vu.nl> <10239@nswitgould.OZ>
Reply-To: ncoverby@ndsuvax.UUCP (Glen Overby)
Organization: North Dakota State University, Fargo
Lines: 40


In article <10239@nswitgould.OZ> nick@nswitgould.OZ (Nick Andrew) writes:
>       As much as I respect the Kermit protocol (and I _do_ respect it),
>it is an inefficient protocol, and does not make full use of Minix's serial
>capabilities. As a non-streaming protocol, it is slow compared to those
>protocols mentioned above.

This holds quite true for the original Kermit specification, but it has
since been expanded to allow long packets and sliding windows.  If I recall
correctly, packets can be up to 64K in length, and there can be 128
outstanding packets.  I have yet to see an implimentation that allows all of
the options; currently most impliment packets up to 1K long and there are
only a few sliding windows implimentations.

Other nice things about Kermit are that it's protocol is written down in one
place (one which is not related to an *implimentation*) and that the authors
of the protocol maintain a collection of implimentations.

To say that kermit is less efficent is quite subjective since there are so
many parameters.  It is unfair to compare an XMODEM derivitive in "maximum"
mode to a kermit in "minimum" mode.  But we're all used to this kind of
comparison, right?? :-)

BTW, I haven't gotten C-Kermit with the diffs posted recently to
assemble/link because asld keeps giving an "out of memory" error (I assume
this is on the output).  Anybody other than the author gotten this one
going?  The earlier "uxkermit" works fine on my (8mhz 8088) system.

>       I have ported Zmodem to Minix.

I haven't seen your diffs yet...They may be "trivial", but they still take
time.

>       By all means, let's keep Kermit, but I don't feel there is a need
>to make it the "standard".

I recall Andy's "Computer Networks" book had an appropriate quote relating
to standards... it was something like "the nice thing about computers is
that there are so many standards to pick from".

Glen Overby     ncoverby@plains.nodak.edu
uunet!ndsuvax!ncoverby                  ncoverby@ndsuvax (Bitnet)