Learning DCOM

by Thuan Thai

DCOM -- the Distributed Component Object Model -- is a recent upgrade of a time-honored and well-tested technology promoted by Microsoft for distributed object programming. Now that components are playing a larger and larger part in Windows 98, Windows NT 4.0, and Windows 2000, every Windows programmer will want to understand the technology. DCOM competes with CORBA as a rich and robust method for creating expandable and flexible components, allowing you to plug in new parts conveniently and upgrade without the need for code changes to every program that uses your component.This book introduces C++ programmers to DCOM and gives them the basic tools they need to write secure, maintainable programs. While using Visual C++ development tools and wizards where appropriate, the author never leaves the results up to magic. The C++ code used to create distributed components and the communications exchanged between systems and objects are described at a level where the reader understands their significance and can use the insights for such tasks as debugging and improving performance.The first few chapters explain both the remote procedure calls that underlie DCOM's communication and the way DCOM uses C++ classes. Readers become firmly grounded in the relation between components, classes, and objects, the ways objects are created and destroyed, how clients find servers, and the basics of security and threading.After giving you a grounding in how DCOM works, this book introduces you to the Microsoft tools that make it all easy. By showing what really happens each time you choose a button in a wizard, Learning DCOM makes it possible for you to choose what you need.This book is for anyone who wants to understand DCOM. While thoroughly practical in its goals, it doesn't stint on the background you need to make your programs safe, efficient, and easy to maintain.Topics

479 pages, Paperback

First published April 1, 1999

Reviews

[Peter Aronson · Rating 4 out of 5]

It is not often I have reason to read an applied technical book this old, but there is a legacy codebase I occasionally work on that was built using COM, and I figured this would explain things about the way it is structured. As it turns out, that code was build using COM, but not Distributed COM (DCOM), the subject of this book,, Fortunately in the process of explaining DCOM, it does a dandy job of explaining COM as well. (And I spent a long time following CORBA, which DCOM is Microsoft's response to. Alas, Object Request Brokers like CORBA and DCOM never took off the way their proponents hoped, but they do live on in certain niches.)

As you would expect from an older O'Reilly book, this is solidly written, well edited, and well focused. It is also something of a period piece, with references to Windows NT and 2000 and Visual Basic, non-ironic use of the term "cyberspace", and an unfortunately optimistic view of the security issues involved in loading software from over the internet. It also has a lot of references to, and screenshots of, obsolete tooling, which is the unfortunate result of being both old and specific.

The description of COM and DCOM internals and architecture are excellent, however, as is the sample C++ code, which is well explained and easy to read. This book might be old enough to vote, but I still found it a worthwhile read.