Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!newstop!sun!amdcad!pepsi!phil
From: phil@pepsi.amd.com (Phil Ngai)
Newsgroups: comp.arch
Subject: Re: Ethernet Factoid
Message-ID: <29801@amdcad.AMD.COM>
Date: 9 Apr 90 23:01:08 GMT
References: <76700190@p.cs.uiuc.edu>
Sender: news@amdcad.AMD.COM
Reply-To: phil@pepsi.AMD.COM (Phil Ngai)
Organization: Advanced Micro Devices, Inc. Sunnyvale CA
Lines: 36

In article <76700190@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
|Five years ago I heard David Redell comment on Ethernet
|standardization.  Dr.  Redell represented Xerox in the
|Xerox/Intel/DEC/IEEE 802 standardization process, in 1979.
|
|He complained that DEC was unreasonable in demanding 10Mb/sec
|performance, when Xerox's 3Mb/sec performance would have been
|perfectly adequate.
|
|Who was right?  Today, PC's (Compaq systempro) are hitting the 10Mb/s
|wall.  How far should a standard push the state-of-the-art, given the
|costs of doing so, the expected lifetime, and the ability to make a
|new standard later?

Xerox's system was based on CATV components. The media cost was
extremely low. I don't know how long it took DEC's media to reach
the point of diminishing returns in terms of economies of scale
but certainly at my company we didn't really start to use Ethernet
until 1985 and at least part of that was due to cost.

DEC made things more expensive in terms of demanding higher speed
*and* longer range. This is why the yellow coax is so thick and
expensive. It seems to me that repeaters and bridges are a much
more attractive solution.

The thin-net stuff seems reasonable enough, however. Even if
Compaq systempros are reaching a limit, that doesn't mean every
PC needs FDDI. Multiple thin-nets to systempros seems like a good
solution, especially if you are using twisted pair Ethernet
where you effectively have multiple nets anyway, as long as your
systempro can be close to the wire closet.


--
Phil Ngai, phil@amd.com		{uunet,decwrl,ucbvax}!amdcad!phil
The War on Drugs is the modern day Inquisition.