Distributed Capabilities

COM supports distributed objects; that is, it allows application developers to split a single application into a number of different component objects, each of which can run on a different computer. Since COM provides network transparency, these applications do not appear to be located on different computers. The entire network appears to be one large computer with enormous processing power and capacity.

Many single-process object models and programming languages exist today and a few distributed object systems are available. However, none provides an identical, transparent programming model for small, in-process objects, medium out-of-process objects on the same computer, and potentially huge objects running on another computer on the network. The Component Object Model provides just such a transparent model, where a client uses an object in the same process in precisely the same manner as it would use one on a computer thousands of miles away. COM explicitly bars certain kinds of "features"—such as direct access to object data, properties, or variables—that might be convenient in the case of in-process objects but would make it impossible for an out-of-process object to provide the same set of services. This is called location transparency.