From: steve@cse.fau.edu (Steve Smith)
Subject: Re: TECH: My standard is better than your standard.
Date: Sat, 1 Aug 1992 20:11:32 GMT
Organization: Florida Atlantic University, Boca Raton, FL, USA



In article <Bs0717.3t8@watserv1.waterloo.edu>
broehl@sunee.waterloo.edu (Bernie Roehl) writes:

>for the poly information.  Average per object: 1220 bytes plus miscellaneous
>timestamp, object i.d. etc.... call it 1300 bytes/object.  Total size of
>the world: roughly 1.3 megabytes.
>
>Compression algorithms will help, but they won't save you much; say a 9600
>baud modem has an effective throughput of 2 kBYTES per second for this kind
>of information.
>
>It would take 650 seconds, or more than 10 minutes, to download the world.

Are you honestly considering implementing this over 9600 bps????

What's the point of having a decent computer if your bandwidth is so
low it will spend most of it's time idle waiting for information to
come in?  I think it is clear that the bottleneck is in bandwidth not
the speed of the CPU/ graphics subsystem.  With your basic RISC box
under $5000, processing speed is not so much the issue it was 3-4
years ago.

Forget about doing this over a modem for now.  I would count on 10Mbps
ethernet or some such medium.  Backbones are getting quick enough we
will soon be able to hook many seperate worlds together but for now I
would limit 1 world to the physical area where a connection of the
requisite speed is available to the router.  Pretty soon we can move
to FDDI or CDDI and run at 100Mbps.

>>[re: 128 bit coordinates and extensibility]
>>That's difficult, because we are defining such a basic parameter, that to
>>make it extensible would drastically degrade performance
>
>But it won't degrade it nearly as much as using 128 bit coordinates, which
>is my point.
>
>There's also the fact that very, very few systems can easily handle 128 bit
>coordinates.

Any system can handle 128 bit coordinates... the issue is performance.
And any system that could be considered for this type of work would be
able to handle them quite nicely.

>>It is said that there are only three numbers in CS. 0, 1, and infinity.
>>(128 bits is the functional equivelant to infinity in this universe anyway)
>
>I'm saying that "infinity" varies from one universe to another.  For the vast
>majority of universes, 32 bits should be the functional equivalent to
>infinity; we can make provision for 128-bit worlds, but it shouldn't be a
>minimum requirement (because it's not a minimum, it's a maximum).

To {mis?}quote someone else who posted here, we should be making
floors not ceilings.

>>I run a 32bit RISC computer.
>
>My point is that the number of people with 32bit RISC computers and custom
>hardware Z-buffering is much, much smaller than the number of people who
>don't.  If we want a world that's only open to those who can pay big bucks
>for their hardware, fine... but that certainly leaves me out, and a lot of
>other people, too.

I don't think this can be done without decent hardware.  Prices are
coming down.  Don't sweat it.

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