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amrameshreddy.blog.comCHAPTER 10■ ■ ■Integrating with COM+This chapter is about working with the past. That past is based upon component technologycreated by Microsoft to provide, at first, a desktop-oriented protocol for reusing applicationlogic. That technology expanded into a distributed technology that helped better positionMicrosoft in the enterprise and provide a challenge to competing technologies.Not without faults, numerous applications were developed based upon this componenttechnology. As a result, we can’t forget the amount of investment by enterprises in this technology.It would damage Microsoft’s credibility and the marketability if Microsoft introduced anew technology that would force an enterprise to scrap its original investments. Therefore,Microsoft and the WCF team worked hard to provide an evolutionary, as opposed to revolutionary,approach for bridging the technological divide, never forgetting the famous quote“Those who cannot remember the past are condemned to repeat it.” 1Introduced in 1993, Component Object Model (COM) was the basis for other emergingtechnologies from Microsoft such as Object Linking and Embedding (OLE), ActiveX, andDistributed COM (DCOM). COM was initially introduced to compete with Common ObjectRequest Broker Architecture (CORBA), a language-independent and cross-platform distributedsystem technology. They did share some core principles, but they were not compatible.Concepts and techniques such as Interface Definition Language (IDL) are present in bothtechnologies. But, binary interoperability didn’t exist.COM+, introduced in 1998, was more of ancillary technology that worked with COM butdid not replace it. Key features of COM+ are transactional components, queued components,role-based security, and object pooling. COM+ 1.5 added features such as application pooling,SOAP services, services without components, and some other features. 2Today, COM+ 1.5 is a core part of the Windows platform. Even with the .NET base classlibrary (BCL) COM interoperability still occurs. Runtime callable wrappers (RCW) are usedthroughout the .NET BCL—one prime example in .NET 2.0 is the web browser control, whichis, as stated in the MSDN documentation, a managed wrapper for the web browser’s ActiveXcontrol. Additionally, serviced components use COM+ transactions.ramrameshreddyramrameshreddy1. Attributed to George Santayana, 19th-century philosopher2. You can learn more in the topic “What’s new in COM+ 1.5” on MSDN at http://msdn.microsoft.com/library/en-us/cossdk/html/e7073ba5-6b19-4d94-8cc0-b4e16bb44afd.asp.301