Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wasatch!cs.utexas.edu!uunet!intercon!amanda@lts.UUCP
From: amanda@lts.UUCP (Amanda Walker)
Newsgroups: comp.protocols.appletalk
Subject: Re: Re: Ethernet vs LocalTalk
Message-ID: <03-May-89.133207@192.41.214.2>
Date: 3 May 89 17:24:16 GMT
References: <24837@ames.arc.nasa.gov> <29980@apple.Apple.COM> <278@suna.CMI.COM>
Sender: news@intercon.UUCP
Reply-To: amanda@lts.UUCP (Amanda Walker)
Organization: InterCon Systems Corporation, Sterling, VA
Lines: 44

In article <24837@ames.arc.nasa.gov>,
medin@cincsac.arc.nasa.gov (Milo S. Medin) writes:
>[regarding Van Jacobson's TCP experiments]
>Wait a sec.  Van got those figures running on a real OS (BSD Unix)
>on properly designed hardware (SUN 3 + Lance chip).  There is *NO
>WAY* you are going to come close with the lousy ethernet controllers
>you get on the MAC-II, and I doubt the Nu-bus can properly
>deal with the transfer rate.  One thing that Van has definitely
>shown is that CPU is not the real problem, it's braindead I/O
>devices!  If you expect real performance, use a real computer.
>
>					Thanks,
>					    Milo

Hmm.  The Mac II I'm posting this from is about the same power as a
Sun 3, Lance chip and all (Dove FastNet III, to be exact).  The NuBus
certainly isn't appreciably slower than the VMEbus in a Sun; I doubt
that's a problem.

One of the other things that Van has also shown is that, even with
a reasonable processor and non-brain-damaged I/O device, the software
that drives it is also important.  After all, vanilla Sun-OS uses the
same hardware as Van's version, and doesn't do nearly as well (or, rather,
it didn't before Sun started whacking on their TCP code :-)).  Van also
keeps asking people not to quote his results out of context, since
the factors he is working with are complex, and cannot be reliably
summarized with "The Lance is better than an 82586" or any of the
other glib versions that have come by since he first started publishing
his findings.

I think you'll find that a Mac II running Apple's MacTCP (which
incorporates most of Van's performance improvements) over an Ethernet
board that uses a Lance (such as a Dove FastNet III) gives quite
respectable performance.  It's certainly as "real" a computer as a Sun 3.

What I'd call a "real" computer isn't a Sun 3, but a network controller
with it's own Lance, 68mumble processor, a half meg or so of fast RAM,
that could run up to the TCP layer in the controller, all without having
to worry about trying to do UNIX at the same time.

--
Amanda Walker
InterCon Systems Corporation
amanda@lts.UUCP / lts!amanda@uunet.uu.net