A Distributed System For Engineering Computing Based On CORBA

Efficient and accurate computer aided engineering computing system plays a key role in the process of engineering design. Only depending on originally computing system of stand-alone version not only can not confirm the coherence of computing results on different systems, but can not satisfy the consumers' requests about computing rate and precision, be against to sharing resources and multi-user cooperating work. This research uses CORBA, a distributed object computing model, as a frame of distributed computing to shield the difference of systems that come from the heterogeneous of hardware and software, make all kinds of resources to be organic consolidate on this platform, and realize distributed engineering computing system based on this frame. At the same time, aiming at the basic situation of our country that there are mainly PC and high performance computers are less, using the parallel computing theory of network, adopting multirworkstation parallel working to resolve the computing problem of thick granularity, and satisfying the rate and precision requests of project computing.This research choose three-layer server mode to realize. In this mode, with the good construction design, the enterprise's behave logic, business logic and data resource can separate independently, apply with different computers, and form client layer, application layer and resource layer.Client layer includes all resources directly related with customers and only need to support browsing HTML pages. Client layer submits Servlet request and sends parameters to HTTP server, HTTP server runs Servlets to call for all kinds of computing service.Application layer includes two parts, one is a HTTP server, and the other is a CORBA management server. The HTTP server accepts concrete applying require of clients, deliver the relevant page stream to client layer as a computing require interface; Moreover, it runs the small programs of Servlets server, monitor and respond to computing requires from client layer. CORBA management server includes the registration information of all objects and provides every kind of service that be needed. The management server accept the reference and parameters of client program about computing objects, search for actual object to realize, accomplish computing and get the return values, and return this value to the client program which sent out requests.Resource layer includes all kinds of traditional servers.In the process of this research, we focus on discussing the transparent interview of client to realized objects, load balance of system computing, and the parallel granularity in the computing process. We also go further into the factors of impacting the system performance,such as communication mechanism, safety mechanism and the mutual-operation of extending system.This research uses the VisiBroker of Inprise Company as the CORBA management server, which is the main base of achieving applications. The VisiBroker can run on local primarily applied operating system, which covers the mapping of main object-oriented program language, and the client programs achieved by any language can be realized by calling for the objects that are achieved by any language.