Windows Programming/DCOM and COM plus

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After the original versions of COM were introduced, there became a clear need to expand the functionality of the COM model, and to make some changes to the general framework. Later versions of COM were given various names, such as DCOM and COM+.


DCOM stands for "Distributed COM", and is a protocol for linking COM components from across a local area network (LAN). DCOM allows COM components to be stored on external "COM servers", and used from other computers in the network.


COM plus = COM + MTS


When the COM design team tried to create a framework that was more easy to use then COM, more portable, and more universal, they created the .NET framework. Originally, .NET was supposed to be introduced as the next version of COM, but instead Microsoft made it into its own entity. COM development has essentially stopped, to focus more attention on the .NET platform.

Because .NET has its roots in COM, it shares many of the guiding principals of COM. First, many different OO languages can be compiled into a single intermediate language. This allows software written in C++, C#, VB.NET, and other .NET languages to be easily interfaced together to create mixed-language programs quickly. In addition, .NET has strong support for distributed computing (a la DCOM). The .NET platform is quickly being standardized, and is available on several different platforms. Therefore, .NET is not strictly a Windows-programming topic, and will likely not be covered much throughout the rest of this book.