Dereos is running with ArribaSIM and a special PHP based gridservice.
This allows a good performance in the grid.
Surabya is a java based cachingserver for inventory structure and textures. It supplies the viewer very quickly with textures and inventory.
Dereos isn't a grid for free registrations. Even the free docking of simulators is not possible.
If you are interested, contact the administrators for more informations.
Arriba & Surabaya
ArribaSIM is a OpenSim fork, developed by Freaky Tech
Surabya is a java based cachingserver for inventory and textures, developed by Akira Sonoda