DCOM (Distributed Component Object Model) is a Microsoft proprietary technology for software components distributed across several networked computers. It is descended from COM, later part of COM+. It has been deprecated in favor of Microsoft .NET.

In terms of the extensions it added to COM, DCOM had to solve the problems of

• Marshalling - serializing and deserializing the arguments and return values of method calls "over the wire".
• Distributed Garbage Collection - ensuring that references held by clients of interfaces are released when, for example, the client process crashed, or the network collection was lost.

DCOM was a major competitor to CORBA. Proponents of both of these technologies saw them as one day becoming the model for code and service-reuse over the Internet.

Ironically, however, the difficulties involved in getting either of these technologies to work over Internet firewalls, and on unknown and insecure machines, meant that normal http requests in combination with web browsers won out over both of them.

External links

• An article from microsoft.com explaining DCOM (http://www.microsoft.com/com/tech/DCOM.asp)