Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!amdahl!amdcad!rpw3
From: rpw3@amdcad.AMD.COM (Rob Warnock)
Newsgroups: comp.dcom.lans
Subject: Re: DEC on Thinwire Stubs?
Message-ID: <21035@amdcad.AMD.COM>
Date: 6 Apr 88 06:01:35 GMT
References: <8803302355.AA28684@decwrl.dec.com> <470008@hpcea.CE.HP.COM>
Reply-To: rpw3@amdcad.UUCP (Rob Warnock)
Organization: [Consultant] San Mateo, CA
Lines: 43

+---------------
| > BTW: Thinwire didn't exist at the time of the original Ethernet
| > standards.  It was added in the IEEE under the name of 10BASE2.
| Nope.  CheaperNet was invented by 3COM.  Traditional Ethernet HW was
| much too expensive for connecting PCs.  The IEEE included it as an
| option in 802.3.  | wunder
+---------------

ACTUALLY... the original project within Xerox for the "enhanced" Ethernet
(the 10 Mb/s one instead of the 3 Mb/s "Experimental EThernet") WAS for a
"thinwire" net, with much the same advantages/limitations as current cheapernet
(which was a term in common use before 3Com claimed it), namely, only about 40
or so taps per cable, and 100-200 meters of cable max. As I understand it, it
was primarily DEC's influence in the "D-I-X" troika which led to the current
(overdesigned for my taste) long, "thick" Ethernet.

Anyway, DEC's idea was to go for the larger-scale net (both in number of taps
and length of cable), on the assumption that the resulting high cost of cable
and transceivers (due to the tight tolerances required) would quickly come down
as volume built up and some chip vendor "integrated" the transceiver. Well,
it happened, but not as fast as anyone hoped, so Ethernet got a (largely
undeserved) reputation for being "expensive".  It didn't help that early
3rd-party controller WERE exhoritantly priced. The actual Ethernet send/receive
function has never been as hard to do as even an ST412 disk, and from technology
considerations alone, the "right" price for a SCSI-Ethernet controller was
the same [at any given point in time] as the price for an SCSI-ST412 disk
controller, say, $250 in 1982 (in 1982 dollars), EXCEPT... that the perceived
high price of Ethernet never generated the volumes that were needed to get
disk controller manufacturers interested in it... until the recent Western
Digital controller...

The internal Xerox 10 Mb/s wire would have been cheaper than current
"cheapernet".  (Of course, the original thin wire transceivers might
not have passed the new FCC RFI/EMI specs that were just coming out
about that time...)


Rob Warnock
Systems Architecture Consultant

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