[Opensim-dev] Thoughts on UUID

[Jani Pirkola]

Dear Sean, Charles,

I have been wondering for a while if it could be a good idea to use hash
values calculated from content instead of random UID for assets (SHA1 could
be used for that). If you upload exactly the same asset to two different
OpenSim grids, the viewers could use the cached version instead of
downloading it twice. I don't know if this is possible, but could help
reducing the bandwidth needs. We could then also make a "standard set of
assets" freely available for everyone and if everybody started to use them,
the users would get immediate benefit from not needing to load same assets
over and over again.
We have at realXtend web site some free assets already available and we
intend to grow that library as we continue our work. Toni Alatalo (antont)
is already using content hash elsewhere (not in realXtend) and could provide
some info if you think this could be a good idea.

Or is the viewer generating the UID? That would then require some changes to
the client and would break the compatibility with SL Viewer..

Jani


2008/4/9, Charles Krinke <cfk at pacbell.net>:
>
> Dear Sean:
>
> It seems like a good idea to me. Perhaps we could do it a sub-project at a
> time, that is by the .dll's and .exe's defined as projects in the windows C#
> IDE.
>
> I would be happy to work through the drudge part. I might like a little
> consultation from time to time, but if you would like, I am happy to
> volunteer to move this one through the code base.
>
> Charles
>
> ----- Original Message ----
> From: Sean Dague <sean at dague.net>
> To: opensim-dev at lists.berlios.de
> Sent: Wednesday, April 9, 2008 11:14:58 AM
> Subject: [Opensim-dev] Thoughts on UUID
>
> One of the things that I ran into today is how many places LLUUID ends
> up in our code base from libsecondlife.  While not always a problem it
> does lead to some oddness.
>
> * libsecondlife is a required link for lots of classes that just need a
>   UUID
> * LLUUID is not serializable, which causes us some pain
> * LLUUID has changed a couple of times in the past, causing us grief
>
> It seems like it would be a good idea to replace LLUUID as much as
> possible with our own OSUUID (I put a sample in
> OpenSim/Framework/OSUUID.cs).  It would look very similar to LLUUID
> (which is basically just a wrapper on System.Guid), but be
> [Serializable].  It would also mean that we could drop a lot of
> libsecondlife references.  I think that would be required for Stefan's
> OpenSim.Model idea.
>
> Thoughts?
>
> This will be a lot of work if we decide to do it, and a couple of days
> of brutal instability to do a swap out like this, as we can't get rid of
> LLUUID entirely (we need it when we get to packet generation I think).
>
> Discussion on this one would be appreciated.  Definitely wouldn't want
> to make any changes like this without full agreement from everyone.
>
>   -Sean
>
> --
> __________________________________________________________________
>
> Sean Dague                                      Mid-Hudson Valley
> sean at dague dot net                            Linux Users Group
> http://dague.net                                http://mhvlug.org
>
> There is no silver bullet.  Plus, werewolves make better neighbors
> than zombies, and they tend to keep the vampire population down.
> __________________________________________________________________
>
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