What are COM, COM+, and DCOM?

COM (Component Object Model) is Microsoft's component software architecture developed primarily for Windows. It is the foundation upon which OLE and ActiveX are based, and provides a means to re-use code without requiring re-compilation. In COM, a component is a platform-specific binary file that compliant applications and other components can utilize. Programs incorporating a component's services never have access to its internal data structure, but instead include pointers to its standardized interface. Thus, it is possible for components to interact with each other regardless of how they work or what language they are written in.

COM+ is an enhanced version of COM that provides better security and improved performance. DCOM (Distributed Component Object Model) is an extension of COM that allows applications and components to communicate with each other over a network.

For more detailed information about COM, COM+, DCOM, and related technologies, visit: http://www.microsoft.com/com/default.mspx

Also see:

• What is the history of Microsoft Windows?
• What is OLE?
• What is ActiveX?
• What are ActiveX controls?