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Actually, I just realized that the problem is already much worse than I
thought.<br>
The practices that we are all doing around opensim completely
invalidate the concept of uniqueness in UUIDs. This comes from the fact
that UUIDs are being externalized into DBs and XML representations,
which are then being imported elsewhere. As people reuse entire DBs and
XML files to recreate the same worlds in different grids, uniqueness
goes down the drain. So definitely, forget about "Universal" Unique
Identification with UUIDs; uris/urls are absolutely required for
universal naming. The only way to savage UUIDs would be use part of
their representation to deterministically code up the ip/port of where
they come from.<br>
<br>
Stefan Andersson wrote:
<blockquote cite="mid:BLU134-W4410B877ADD3936F95135CD5230@phx.gbl"
type="cite">
<style>
.hmmessage P
{
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}
</style>And the whole thread started with suggesting we allocate
information bits to encode semantics. Which drastically heightens the
risk of collisions, intentional or malicious.<br>
<br>
Just see guids as private to the trust domain, and we'll all fine.
Grids should be publicly referred to by something riches, as an uri/url
for example.<br>
<br>
Best regards,<br>
Stefan Andersson<br>
Tribal Media AB<br>
<br>
Join the 3d web revolution : <a moz-do-not-send="true"
href="http://tribalnet.se/" target="_blank">http://tribalnet.se/</a><br>
<br>
<br>
<br>
<br>
<hr id="EC_stopSpelling">
<br>
Date: Fri, 31 Oct 2008 20:10:41 -0700<br>
From: <a class="moz-txt-link-abbreviated" href="mailto:diva@metaverseink.com">diva@metaverseink.com</a><br>
To: <a class="moz-txt-link-abbreviated" href="mailto:opensim-users@lists.berlios.de">opensim-users@lists.berlios.de</a><br>
Subject: Re: [Opensim-users] [Opensim-dev] Grid Numberging<br>
<br>
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Not to mention the dudes and dudettes who generate region UUIDs by
hand... (a-hem)<br>
Purely random UUIDs that don't encode higher-order information are too
fragile when there is a chance that people will get their hands on
them. I'm not even talking about malicious manipulation, just simple
human intervention.<br>
<br>
Frisby, Adam wrote: <br>
<blockquote
cite="mid:63FAD4F222230A4EA79DE9E8BE6647352BE843@winxbeus19.exchange.xchg">
<pre>Yeah, the reason I said 'almost' wasn’t because of a good UUID generator, - it's the bad ones.
IE, people using bad random sources, etc which dramatically increase the chance of a collision - ie if you are only getting 30 bits of randomness, you could run into a collision fairly quickly.
Adam
</pre>
<blockquote>
<pre>-----Original Message-----
From: <a moz-do-not-send="true" class="EC_moz-txt-link-abbreviated"
href="mailto:opensim-users-bounces@lists.berlios.de">opensim-users-bounces@lists.berlios.de</a> [<a
moz-do-not-send="true" class="EC_moz-txt-link-freetext"
href="mailto:opensim-users">mailto:opensim-users</a>-
<a moz-do-not-send="true" class="EC_moz-txt-link-abbreviated"
href="mailto:bounces@lists.berlios.de">bounces@lists.berlios.de</a>] On Behalf Of Sean Dague
Sent: Friday, 31 October 2008 4:48 PM
To: <a moz-do-not-send="true" class="EC_moz-txt-link-abbreviated"
href="mailto:opensim-users@lists.berlios.de">opensim-users@lists.berlios.de</a>
Subject: Re: [Opensim-users] [Opensim-dev] Grid Numberging
Dr Scofield wrote:
</pre>
<blockquote>
<pre>Frisby, Adam wrote:
</pre>
<blockquote>
<pre>Shouldn’t UUIDs by definition be unique?
IE – if your generating them randomly a collision is almost
guaranteed to never ever occur.
</pre>
</blockquote>
<pre>"almost" being a key word here...
</pre>
</blockquote>
<pre>"...after generating 1 billion UUIDs every second for the next 100
years, the probability of creating just one duplicate would be about
50%. The probability of one duplicate would be about 50% if every
person on earth owns 600 million UUIDs.<a moz-do-not-send="true"
class="EC_moz-txt-link-rfc2396E"
href="http://en.wikipedia.org/wiki/UuidJusttokeep" target="_blank">"
http://en.wikipedia.org/wiki/Uuid
Just to keep "</a>almost" in perspective,
-Sean
--
Sean Dague / Neas Bade
<a moz-do-not-send="true" class="EC_moz-txt-link-abbreviated"
href="mailto:sdague@gmail.com">sdague@gmail.com</a>
<a moz-do-not-send="true" class="EC_moz-txt-link-freetext"
href="http://dague.net/" target="_blank">http://dague.net</a>
</pre>
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