Overview

Microsoft's DCOM (Distributed Component Object Model) is based on Microsoft's own COM (Component Object Model). COM defines how components interact and is an architecture for simple interprocess communication. It defines a basic model of communication using Microsoft's equivalent of objects components. DCOM supports the same model of component interaction, but supports distributed interprocess communication. Thus DCOM is an architecture that enables components (processes) to communicate across a network.

The architecture includes two types of service services provided at runtime and services the developer can use to develop distributed applications.

Examples of the sorts of service provided at runtime include security services (authorization, authentication, and encryption), load balancing, guaranteed delivery, deferred delivery, triggering, automatic multithreading, shared memory management, distributed transaction support, message queuing support, broadcasting, multicasting, time services, synchronization (support for asynchronous and synchronous communication), context bridging, routing, plus many more.

Very few people realize just how extensive the service support in DCOM is until they "get under the covers." DCOM enables the developer to completely avoid having to write complicated communication code at the low level sockets or network software level. Thus DCOM takes care of all the communication between machines. DCOM is also supplied with a set of runtime libraries that handle all the functions of communication session handling, synchronization, data format translation, buffering, and fault identification and handling.

We will be describing what each of the services means, what it aims to do, and how Microsoft has tackled the problem in this book. The main objectives in providing...