Guru's Guide to SQL Server Architecture and Internals, The

The Dawn of COM

Microsoft's answer to these problems was COM. Simply put, COM provides an interface to third-party code libraries that is

• Object-oriented

• Centralized

• Versioned

• Language-neutral

Since COM uses the system registry, the days of unmanaged or improperly used configuration information are gone. When an application instantiates a COM object (usually through a call to CreateObject), Windows checks the system registry to find the object's location on disk and loads it. There's no guesswork, and multiple copies of the same object aren't allowed—each COM object lives in exactly one place on the system.

NOTE: Microsoft has recently introduced the concept of COM redirection and side-by-side deployment. This allows multiple versions of the same ...