Design And Implementation Of The Distributed Multi-tier Architecture Based On DCOM In PSMIS

With the development of the Internet/Intranet, the operation mode of enterprisers in the past have been changed accordingly, and the system of computer application have changed the computing method from mode of single machine to network computing. The mode of multi-tier distributed architecture came into being in this environment. Compared with the conventional tow-tier mode, the multi-tier architecture makes the business centralized control, and brings the real "thin client" into success, all this will cause more expandability and scalability in the system.PSMIS is the shortened form of Power Supply Management Information System. Through the computer technology, PSMIS, which can provide the reliable implementation of the complex business for power supply department, and monitor the real-time state of the devices and the state of the employees in the spot, will provide the veracious information and warrant of decision for managers and decision-makers in time. In the large-scale application system of the enterpriser such as PSMIS, because of heavy and complex business, multitudinous user, the key for success will be the choice for the architecture. The system architecture will affect the control methods of the business rule, expandability and maintainability in the system, the capability of load balance and the security of the data. Therefore the subject study for the design and implementation of the multi-tier distributed architecture in PSMIS has practical meaning in some degree.The multi-tier architecture mode is based on the distributed technology that include tow main technology: DCOM and CORBA. The paper will introduce the technical feature and operating principle of DCOM and CORBA. Because of the merits of DCOM in installation and rate of execution we choose it for the basic technology of the distributed environment. Based on the comparison and analysis between multi-tier distributed architecture and conventional tow-tier mode of C/S, the paper puts the focus on the merits of the former in maintainability, scalability and data security of the system. The paper presents the resolution of hierarchical multi-tier architecture for PSMIS, which willimplement the distributed computing in business an architecture hierarchy.In order to ensure the well-known feature clarity and definitude in the architecture hierarchy, we severely follow the development standard of the multi-tier architecture and complete the code layer by layer in the implementation of the PSMIS. The paper presents a simple example of PSMIS business, and gives the code of the implementation that based on MIDAS. The paper emphasizes the development standard and code rule of the multi-tier architecture.