Sonata

Sonata is an object-oriented, multi-person, multi-interface, persistent, programmable, real-time, collaborative, distributed, persistent infrastructure for constructing shared, administered and extensible virtual worlds. By using a language with a distributed semantic, the complexity of building such an infrastructure is reduced. We are not restricted by having to take desicions about the distribution structure our program in an early phase of the project. Neither do we have to write a lot of extra code to take care of the distribution between sites.

Some of the questions we are asking ourselves at the moment are

• Distribution. Mozart offers transparent distribution of entities, but there is still a lot to do to reduce the complexity of distribution for the "world"-programmer. What distribution behavior do we want if we consider taking care of network failures or site crashes?
• Extensible. How do we make it possible for clients to upload new source code at runtime or even upgrade existing code?
• Resource accounting. How to manage resource accounting if clients are allowed to upload new code (or modify existing) at runtime.
• Persistence. How can we manage persistens for a virtual world? How do we handle persistens when the application is running on maybe hundreds of computers? Is there a way to have some kind of incremental algorithm that doesn’t freeze the system for a long period of time?
• Fault tolerance. How can we minimize the affect of network failures or site crash for the participants in a virtual world?
• User-interfaces. What kind of user-interfaces can we advantage of, besides traditional telnet clients? Sonata will have the possibility to create sophisticated user-interfaces using Tcl/Tk and/or OpenGL.

Another aspect of the Sonata project is to explore what functionality a programmer of a large distributed application wants. For example Mozart offers no capabilities to handle persistens, security (besides language security) or to use different network protocols (e.g. UDP or multicast).

To test some ideas I wrote a small prototype of Sonata. The screenshots on this page are from this prototype. The whiteboard is not mine, I have just provided the glue to make it fit into Sonata. More information about the whiteboard is found here. If you want more information about Sonata do not hesitate to send me an email!

SICS, Box 1263, S-16429 Kista, Sweden phone: +46 8 633 1500, fax: +46 8 751 72 30 mail: info@sics.se