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From: staff@cadlab.sublink.ORG (Alex Martelli)
Newsgroups: comp.arch,comp.editors
Subject: Re: Quote from new book
Message-ID: <651@cadlab.sublink.ORG>
Date: 20 Jan 91 19:43:52 GMT
References: <1046@grit.cs.utexas.edu> <3349@uc.msc.umn.edu> <21349@oolong.la.locus.com>
Followup-To: comp.arch
Organization: CAD.LAB, Bologna, Italia
Lines: 48

jfr@locus.com (Jon Rosen) writes:
	...
:By the way, this is also why I think Plan 9, as described in several
:recent mags, is severely broken... The emphasis is on terminal servers
:for interaction with the file and CPU servers... thus, no user will
:have a true local computing capability... Why is this still being
:considered??? We can now buy Sparc chips running 15Mips at a cost

Plan 9's PU-servers are MULTI-processor machines, to be dimensioned at
about 1 processor PER PROCESS concurrently executing, that is, MORE
than 1 processor/user if the typical users are doing significant
computation (rather than just data-access tasks, handled in the file
server, or terminal-interaction, handled in the gnot).  1 to 3 mbit/sec
from the gnot to the file-and-CPU-servers'-cluster are claimed to be
enough for subjectively-instantaneous interaction, so with high speed
remote connections becoming cheaper and widely available in the future,
this would allow anybody to have "his/her own computer" at hand anywhere
in the world - working from home or from office or on a trip without
even noticing the difference, and so on.

I'm not defending (or attacking!) this system-architecture approach,
just putting right a misconception on the NUMBER of CPU's per user that
it is predicated on!

:386s...  The Plan 9 article in DrDobbs used the COST of workstations
:as a justification for using X-type terminals!!! What is missing is

Given that Plan 9's authors made the UKUUG meeting's prize competition
be on the most fitting INSULT for X, I think you should expect their
seconds (as in "duel"!) after this...:-).  Cost of a very powerful
workstation, say a SS-2, MIPS Magnum, Decstation-5000, or IBM RISC-6000,
is not a joke when you equip it with a nice amount of memory - we're
looking at 40K$ to 50K$ easily (list), and how long will it be before
you would really prefer to upgrade it?


:Let's hear it for Jerry Pournelle's law: (At least) one Cpu per
:user... (and now at least three)...

Definitely not violated by Plan 9.  Please do redirect followups to
comp.arch, as suggested in my header, as the relationship to editors
seems tangential at best, while comp.arch has been recently filled with
non-architectural discussions...!
-- 
Alex Martelli - CAD.LAB s.p.a., v. Stalingrado 53, Bologna, Italia
Email: (work:) staff@cadlab.sublink.org, (home:) alex@am.sublink.org
Phone: (work:) ++39 (51) 371099, (home:) ++39 (51) 250434; 
Fax: ++39 (51) 366964 (work only), Fidonet: 332/401.3 (home only).