Scientists Dream of Jini.(Company Business and Marketing)

The Java-based Jini network technology gives rise to a distributed environment for scientific visualization

Visualizing 3D fluid flows is one of the most computationally challenging tasks in scientific visualization. For that reason, researchers in the Computer Graphics and Scientific Visualization Group of the Politecnico di Torino in Italy chose the application as a "test case" to evaluate the merits of a novel distributed computing environment for scientific visualization based on Sun Microsystems' Jini technology.

Jini is an architecture that provides a simple infrastructure for delivering services over a network and for creating spontaneous interaction between programs that use these services, regardless of their hardware or software implementation. With Jini, any kind of network made up of "services" (such as applications, databases, servers, devices, information systems, mobile appliances, storage, and printers) and clients of those services can be easily assembled, disassembled, and maintained on the network. Moreover, services can be added or removed from the network, and new clients can find existing services--all without administration. Thus, with Jini, devices can plug together without any planning, installation, or human intervention. Each device provides services that other devices in the community may use. These devices provide their own interfaces, which ensures reliability and compatibility.

These capabilities make the technology particularly appealing for high-end CFD visualization, for which a distributed architecture is considered a must. "Many visualization algorithms could be too computationally onerous for a single workstation," says principal researcher Andrea Sanna, because of insufficient computational power and insufficient space for storing the gigabytes of data that CFD simulations can produce. "Also, some visualization algorithms like raytracing or ray casting, which are used to show optical effects such as reflection, refraction, and shades, need powerful or parallel computers?' Executing the "heavy" calculations on a supercomputer and leaving the lighter ones for low-end computers overcomes the constraints of single-machine systems.

The appeal of the Jini technology for CFD and other visualization applications lies in its simplicity and openness, according to Sanna. "There are a few distributed visualization systems, but most of them employ proprietary technologies [for specific applications]." In contrast, he notes, Jini, which is available as freeware, is application-independent and functionally "transparent" For example, he says, "developers only have to know the Java language, and client developers have to know only the interface for using a remote service, not the underlying code?' Jim operates quietly in the background, pulling all of the pieces together.

Connecting Together

A typical Jini architecture comprises three components: clients, servers, and a look-up service. Each server and client registers itself to the lookup service. When the client registers, it specifies the servers that it needs. "In our [fluid ...