Active Directory, Second Edition

WMI Architecture

The WMI architecture is composed of two primary layers: the CIM infrastructure, which includes the CIMOM and CIM Repository, and the WMI providers. While the concepts Microsoft uses are very similar to the WBEM/CIM standards, they did not implement one very important component: the use of web technologies for the transport mechanism. Instead of using HTTP to transport messages between the WMI infrastructure and clients, Microsoft uses COM and DCOM, two Microsoft-specific technologies. This limits the use of WMI to only Microsoft platforms.

That being said, the capabilities to manage Microsoft-based platforms with WMI are nearly unlimited. More and more vendors are utilizing WMI not only to manage components of the Microsoft OS but also to manage their own applications. NMicrosoft has also become heavily invested in WMI by providing WMI providers for nearly all of its major applications, including Active Directory, Exchange 2000, DNS, and even Microsoft Office.

CIMOM and CIM Repository

The CIM Repository is the primary warehouse for management data. It contains the static data that does not change very frequently, such as memory or disk size. The CIMOM or CIM Object Manager handles requests from clients, retrieves data from the CIM Repository, and returns it to the client. The CIMOM also provides an event service, so that clients can register for events and be notified dynamically when they occur. For dynamic data, such as performance monitor counters, the CIMOM will ...