Figure 4.1 illustrates the internal structure of the Store in Exchange 2000. At first sight, there might not appear to be too many changes to Exchange 5.5, but some fundamental and strategic restructuring has occurred under the hood.

Figure 4.1: The structure of the Exchange 2000 Store

The Store Kernel is the component that builds features unique to Exchange on top of the generalized Jet Blue engine. These features include single instance storage, views, and automatic indexing of items as they are added to the Store. The Jet Blue layer is built on top of the generalized ESE database engine. This layer takes responsibility for managing low-level internal structures such as the B-trees and class tables. ESE has no knowledge of high-level structures such as the schema used in any particular database. Instead, ESE operates at the page level to manipulate database contents.

We've referred to Jet and the blue hue that's applied to the Store. Jet stands for Joint Engine Technology, a generalized database engine on which Microsoft builds products such as the Store and Access, the personal database manager. ESE is a much-enhanced development of the basic Jet engine that is now used by the AD, the DS, and other components such as KMSMDB.EDB, the Key Management (security) database and XDIR.EDB, the database used to synchronize directories between Exchange and Microsoft Mail. Apart from Exchange and Access, there are many other examples of Jet in use within Microsoft products. For example, both WINS and...