Interpretation of COM and CORBA (lower) technology comparison (Author: Shi Xiaojun compile April 2001 13 Ri 13:53) CORBA IIOP remote objects is dependent on communication, DCOM objects depends on the remote procedure call handling (ORPC) to achieve the same purpose . The CORBA architecture is based on object request agency; DCOM is based on COM as its basis, transaction depends on MTS or MSMQ. The CORBA specification is not for specific vendors, so CORBA applications can run on different hardware platforms. DCOM is made by Microsoft, the architecture, and can only run on the hardware platform supported by Microsoft operating systems. CORBA supports multiple inheritance, and DCOM only supports single inheritance. DCOM uses ping to check if the customer is still active, if the customer still does not respond more than six minutes, the DCOM will cancel the customer request. Conversely, CORBA does not force customers to maintain the connection state and do not use the communication method that holds the active state. Since the DCOM uses a communication mode that keeps an active state, it can decide when to cancel the request, thereby using built-in garbage collection function; CORBA does not provide a built-in garbage collection method. In terms of use ● COM / DCOM COM / DCOM is Microsoft's architecture, which is only supported by the operating system of the Windows family. Anyway, there are third-party manufacturers with DCOM support on UNIX systems. DCOM is based on natural binary format, so it is faster, but it does not apply to other platforms. The COM / DCOM component can access the Windows API, so it can potentially damage or endanger the user's computing environment. DCOM provides basic support for distributed objects, but does not support real-time processing, nor is it suitable for use under high reliability. Although COM has already had a long time, but for its extension DCOM, in a large number of prospects in distributed applications, it is not very clear. ● CORBA CORBA is just a specification, not an implementation, so users are difficult to determine if the purchased product is fully compatible with CORBA. And there is no defined test suite to test whether it is compatible with CORBA. For customers, you need to have a hipster to evaluate the manufacturer's products. CORBA is a complex specification that requires considerable experts to develop distributed objects and applications. On the other hand, using CORBA, it is easy to develop distributed applications. Of course, there are many experts who need to design, distributed, multi-threaded program design and debugging, intranet, and object-oriented analysis, design, design, and object-oriented analysis. Using comparison CORBA provides cross-platform support, COM / DCOM is limited to Microsoft operating systems. Corba and COM support components written in different programming languages. CORBA objects are based on a standard specification promulgated in 1991; COM specification and code are in a non-stop-changing process, and its document is just a draft. COM was originally designed to run on a single machine, not a large-scale network. In any case, Corba is designed in large-scale distributed applications from the beginning. There are many developers who provide CORBA products, while COM / DCOM can only be obtained from Microsoft. The CORBA specification is defined by OMG. Its members can reflect the needs of the industry, while COM / DCOM is owned by Microsoft. Its specification is calculated by Microsoft. Conclusion For distributed calculations, COM / DCOM and CORBA have scalability and robust structure, and have their own different advantages. In any case, given their inherent differences, they apply to applications with different sizes and types, respectively.
