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From: jg@crl.dec.com (Jim Gettys)
Newsgroups: comp.unix.ultrix,comp.windows.x,comp.sources.wanted
Subject: Re: FOLLLOWUP TO: X11R4 on DEC 5000 Ultrix 4.x
Keywords: X11R4, DEC 5000, server, Ultrix 4.x
Message-ID: <1991May10.005658.12215@crl.dec.com>
Date: 10 May 91 00:56:58 GMT
References: <2692@sierra.ACA.MCC.COM> <1991May8.235652.2246@crl.dec.com> <1991May9.192546.18589@news.arc.nasa.gov>
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Organization: DEC Cambridge Research Lab
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Originator: jg@jg.crl.dec.com

In article <1991May9.192546.18589@news.arc.nasa.gov> schoch@trident.arc.nasa.gov (Steve Schoch) writes:
>In article <1991May8.235652.2246@crl.dec.com>, jg@crl.dec.com (Jim Gettys) writes:
>|> The biggest reason for vendors to convert to R4 servers are two things:
>|> 1) better memory utilization
>|> 2) higher performance, particularly for windowing operations.
>|> Many/most of 2) were implemented by Digital, and the results given to
>|> MIT for R4, so it has been less pressing for us to convert than most
>|> manufacturers.
>
>There are a couple of other, more obscure reasons:
>
>1) The R4 server handles new connections differently.  Try this on your
>workstation:  telnet <your workstation> 6000
>If you are running R4, you telnet will connect and your server will go
>about its business of dealing with other clients.  If your are running
>R3 (e.g. DECwindows) your server will freeze for about 60 seconds.  The
>reason for this can be seen by looking in the routine EstablishNewConnections
>in server/os/4.2bsd and comparing R3 against R4.  The scary thing is that
>anyone on the network can freeze your server this way whether they are
>authorized to connect to your display or not.
>
>2) The R4 server has a way of giving access to your server on a per-
>client basis in addition to the per-machine method of R3.  If you do
>all of your work on your workstation you probably don't care about this,
>but if you run clients from a "public" machine it is nice that other
>users on that machine can't do nasty things to your display (e.g. "bounce").
>

Yup.  You are correct; if we want to get more obscure, I can do so.
How obscure do you want me to be?  I bet I can out trivialize all
but 3-4 people in the world on X trivia :-).

I just mentioned the two biggest reasons, one of which is less of a reason
on our systems than on most other vendors.  I didn't mean to imply there
aren't lots of other minor reasons...

As my mail said, UWS 4.2 is about to appear in customer's hands, and
it uses R4 servers for most hardware.  Folks are working hard to
make it ALL the hardware.
				- Jim

-- 
Digital Equipment Corporation
Cambridge Research Laboratory