Inside Distributed COM (Mps)
Although Microsoft's Distributed Component Object Model (DCOM)  is one of the most widely used component standards in the computing  industry, it has a well-deserved reputation for being rather difficult  to master. While many tools (such as Visual Basic) let programmers use  DCOM without understanding how it works, C++ and Java programmers who  need to know more will want to turn toInside Distributed  COM. This surprisingly readable reference mixes enough technical  detail with actual source code drawn from C++, Java, and Visual Basic  to show how DCOM really works.The authors start out simply,  identifying the basics of COM running on a local machine, and run  through the essentials of what COM objects are and how they promote  reuse. They present the basic interfaces of COM and discuss the  philosophy of COM's object design regarding containment and  aggregation. (Although COM does not support inheritance, it can  simulate such relationships in other ways.)After laying the  theoretical groundwork, the book features several excellent  nuts-and-bolts chapters that demonstrate how COM works in several  programming languages: C++ (including the Active Template Library),  Java (which hides many of the details of COM programming), and Visual  Basic (which makes using COM transparent to programmers). The short  examples drawn from each language show how COM is an essential part of  the Microsoft programming languages and tools.The book moves into  more of the technical aspects of COM, such as automation (for  scripting COM components), connection points (for event handling),  monikers (for identifying COM components regardless of their location  on the network), and marshaling (which lets objects send data between  objects). The authors mix in a useful amount of theory while  consistently holding the reader's interest. A chapter on threading  models (a difficult topic) is also particularly clear, and the authors  even provide their "ten commandments" for threading  models--rules that show when to use single or multiple threading  apartments.Later chapters discuss distributed computing and the  problems that need to be solved as COM moves to distributed  systems. These chapters include the advantages to in-process servers  versus stand-alone processes in distributed architectures and a full  discussion of the Microsoft Interface Definition Language (IDL), which  allows components to talk to one another.The book closes with new  technologies, including how developers can benefit from using  Microsoft Transaction Server for robust transaction management and how  the emerging COM+ standard will add even more to the mix, with  services that rival CORBA for enterprise-wide distributed  computing.Inside Distributed COMmay be the best guide to  understanding COM, whether you are running it on a single machine or  multiple machines. The authors succeed in highlighting what you should  understand about this important technology in order to become a more  effective developer or information services manager.