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From: mark@mimsy.UUCP (Mark Weiser)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Ethernet Suffering
Message-ID: <6603@mimsy.UUCP>
Date: Fri, 8-May-87 18:19:15 EDT
Article-I.D.: mimsy.6603
Posted: Fri May  8 18:19:15 1987
Date-Received: Sat, 9-May-87 21:23:46 EDT
References: <8705070548.AA10268@ucbvax.Berkeley.EDU> <34bd5209.c366@apollo.uucp>
Reply-To: mark@mimsy.UUCP (Mark Weiser)
Distribution: world
Organization: Heterogeneous Systems Lab, University of Maryland
Lines: 28

In article <34bd5209.c366@apollo.uucp> mishkin@apollo.UUCP (Nathaniel Mishkin) writes:
>...I think the recent discussion
>in this group highlights some of the virtues of token ring networks.
>I was fairly astonished to hear read one basically can run no more than
>(based on the various estimates) 8-15 diskless workstations (of some
>manufacture) on a single ether. 

I think this is a misinterpretation of the comments.  I have seen
Apollo networks exhibiting extremely poor performance when too many
diskless nodes were accessing a single server.  (Too many did not
seem to be all that many--I saw this at the Brown demonstration
classroom, when all the diskless clients were trying to start at
once.)  I think that the question is:  what does it mean to 'run
no more than...'.  Sure you can run more than 8-15, but the
performance will look worse.  If you are used to a local disk, then
you can 'feel'  the decrement with more than 8-15 diskless workstations
on the ethernet.  On the other hand, if you are willing to accept
low-performance transients (as the Brown folks evidently were on their
Apollos during startup), then you can do more.

Another angle: there are lots of reasons why performance could be different
between these two systems.  It is premature to point the finger at the
0/1 networking levels without more information.

-mark
-- 
Spoken: Mark Weiser 	ARPA:	mark@mimsy.umd.edu	Phone: +1-301-454-7817
After May 15, 1987: weiser@parcvax.xerox.com