TechEd 99 - Box on COM

Introduction to COM (Don Box)

July 6 - For a lively and entertaining introduction to COM it may be hard to find a better speaker than DevelopMentor's Don Box. After presenting two sessions on the first day of TechEd 99, his grip over the audience was so strong that by the end delegates were on their feet and performing breathing exercises while waving their arms in the air.
    Don kicked-off by taking the assembled crowd through the basic reasoning behind COM. He managed to distill this down to three "good ideas", namely programming in terms of interfaces rather than classes; code being loaded on demand at runtime, and not statically linked; and object implementors declaring their runtime requirements, leaving the system itself to ensure those requirements are met. Don's first session concentrated on the first of these, while the second session covered the remaining two.
    The motivation for COM isn't hard to find, as Don explained. Developers want to build systems that can be composed dynamically, have plug-and-play replacement and extensibility of components, and where the effect on the system of changes to the code is minimised. On top of these can be added a desire for components with differing runtime requirements to live in harmony, and for the liberation from file/path dependencies.
    Taken together, both sessions provided an overview of what can be gained from COM, and an insight into how COM is implemented. It did help to have a good understanding of C++, although most of the code examples were kept simple. Don certainly demonstrated how to make a potentially dry subject both interesting and amusing!

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Head-to-head: Don Box on COM+