In addition to supporting the Component Object Model (COM) for interprocess communication on a local computer, Windows 2000 supports the Distributed Component Object Model (DCOM). DCOM is a software object system designed to be reusable and replaceable. Objects are software components that can make and support applications. Objects support sets of related functions such as sorting, random number generation, and database searches. Each set of functions is called an interface, and each DCOM object can have multiple interfaces. When applications access an object, they receive an indirect pointer to the interface functions. The pointer has information about the location of an object. After receiving this pointer, the calling application does not need to know where the object is or how it does its job since the pointer directs the calling application to it.
DCOM enables processes to be distributed efficiently to multiple computers so that the client and server components of an application can be placed in optimal locations on the network. The processing is done transparently for the user because DCOM controls this function. Therefore, the user can access and share information without needing to know where the components of the application are. If the client and server components of an application are on the same computer, DCOM can be used to transfer information between processes. DCOM is platform independent and supports any 32-bit application that is aware of DCOM.
DCOM is a preferred method by developers to use in writing client / server applications for Windows 2000. With DCOM, interfaces can be added or updated to software objects, so applications are not forced to update every time Change the software object. Objects are software entities that perform specific functions. These functions are implemented as dynamic-link libraries so that changes in functions, including new interfaces or function operation, can be performed without rewriting and recompiling the applications that call them.
Windows 2000 supports DCOM by making the implementation of application pointers transparent to the application and object. Only the operating system needs to know if the called function is handled in the same process or through the network. This frees the application of concerns with local or remote procedure calls. Administrators can choose to run DCOM applications on local or remote computers and can change settings for efficient load balancing.
