FAQ 34.05 What is a binary object model ?

FAQ 34.05 What is a "binary object model"?

Component architecture defined at the machine level.

COM is called a binary object model because the COM specification defines how objects are laid out in memory (hence binary). This permits any programming language or any development tool to create a COM object as long as it is capable of laying out the memory in a manner that conforms with the COM specification and calling the appropriate COM routines.

Compare this to an object-oriented language, like C++, which defines classes and objects using a language object model. Specifically, C++ defines what constitutes a legal class definition in terms of the syntax and semantics of a programming language and then leaves it up to the compiler to translate the source code into an executable program.

In reality, COM is not Windows-specific; there are COM implementations for other operating systems (in particular, Software AG has ported COM/DCOM to Sun Solaris, 64-bit Digital Unix, and IBM's OS 390), but COM was designed with Windows as its first and foremost priority.