[Opensim-users] [Opensim-dev] Grid Numberging

[Diva Canto]

Actually, I just realized that the problem is already much worse than I 
thought.
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.

Stefan Andersson wrote:
> And the whole thread started with suggesting we allocate information 
> bits to encode semantics. Which drastically heightens the risk of 
> collisions, intentional or malicious.
>
> 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.
>
> Best regards,
> Stefan Andersson
> Tribal Media AB
>  
> Join the 3d web revolution : http://tribalnet.se/
>  
>
>
>
> ------------------------------------------------------------------------
>
> Date: Fri, 31 Oct 2008 20:10:41 -0700
> From: diva at metaverseink.com
> To: opensim-users at lists.berlios.de
> Subject: Re: [Opensim-users] [Opensim-dev] Grid Numberging
>
> Not to mention the dudes and dudettes who generate region UUIDs by 
> hand... (a-hem)
> 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.
>
> Frisby, Adam wrote:
>
>     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
>
>       
>
>         -----Original Message-----
>         From: opensim-users-bounces at lists.berlios.de <mailto:opensim-users-bounces at lists.berlios.de> [mailto:opensim-users-
>         bounces at lists.berlios.de <mailto:bounces at lists.berlios.de>] On Behalf Of Sean Dague
>         Sent: Friday, 31 October 2008 4:48 PM
>         To: opensim-users at lists.berlios.de <mailto:opensim-users at lists.berlios.de>
>         Subject: Re: [Opensim-users] [Opensim-dev] Grid Numberging
>
>         Dr Scofield wrote:
>             
>
>             Frisby, Adam wrote:
>                   
>
>                 Shouldn’t UUIDs by definition be unique?
>
>
>
>                 IE – if your generating them randomly a collision is almost
>                 guaranteed to never ever occur.
>                         
>
>             "almost" being a key word here...
>                   
>
>         "...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."
>
>         http://en.wikipedia.org/wiki/Uuid
>
>         Just to keep " <http://en.wikipedia.org/wiki/UuidJusttokeep>almost" in perspective,
>
>                 -Sean
>
>         --
>         Sean Dague / Neas Bade
>         sdague at gmail.com <mailto:sdague at gmail.com>
>         http://dague.net <http://dague.net/>
>
>             
>
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>       
>
>
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>
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