Application and tools for distributed computing technology, currently mature technologies include J2EE, CORBA, and .NET (DCOM), which is very wide, and there are many related books, this article does not introduce these technologies, There is no detail involving these technologies, just from the background generated by various distributed system platforms and situations in software development to explore their main differences. I. Formation of distributed computing technology CORBA (Common Object Request Broker Architecture) is proposed by OMG (Open Management Group) organized by OMG (Open Management Group) 1992. At that time, the distributed application environment used a Client / Server architecture, and CORBA's application improved the development efficiency of distributed applications. Another distributed system development tool at that time is Microsoft's DCOM (Distributed Common Object Model). Microsoft implements OLE (Linked and Embedded Object) technology in order to call each other in the Windows platform. (For example, editing the Excel file directly in Microsoft Word), Technology is derived from Common Object Model. With the popularity of Internet and the wide application of web services (Web Services), the Browser / Server architecture is gradually reflected in its advantage. Thus, Sun Company launched a development and application platform for J2EE applications in the B / S architecture on its Java technology; Microsoft also launched .NET development and application of B / S applications on the basis of DCOM technology. platform. Second, the DCOM technology covered in the use of the protocol. Like the CORBA, the TCP / IP protocol is used in the network transport layer; also has its own IDL specification. The difference is that on the TCP / IP, CORBA uses the Giop / IIOP protocol, all CORBA servers communicate with IIOP, forming an ORB software channel; J2EE's RMI has adopted an independent communication protocol, which has been changed to RMI / IIOP, The openness of J2EE; DCOM also has its own communication protocol (TCP service at 135 port), but Microsoft did not open this protocol specification; the same, CORBA's IDL's definition of C , is an open specification; DCOM IDL Although the document is in the form of text, Microsoft does not formally announce its specification, in use, .NET IDL is generated by the development tool. Third, the environment of the application is about .NET, Bill Gates said this: "Simply said that .NET is based on Microsoft's various products for development tools and application platforms to implement XML-based network services." It can also be seen .NET is powerful in Microsoft's world, but for UNIX and Linux, these systems in the server market, .NET appears to be helpless. Therefore, J2EE shows its cross-platform advantage, providing network service providers with a good development and application platform for Front-end, with network services further widely applying and service integration, online services The provider's background will form a large-scale distributed computing environment, and the CORBA module structure is more suitable for a variety of services in the background, such as a web service billing program. It can be seen that J2EE and CORBA technology can be seen. In the web service (Web Services) this blue sky, each has its own ocean and land. If the .NET development platform is used at the front-end, the DCOM is an ideal choice in the distributed structure of the back-end.
