Microsoft® Windows® XP Unleashed

What Is the Active Directory?

The Active Directory changes the landscape dramatically. Active Directory uses domains, although simply as an organizational unit in the Active Directory database. The Active Directory also still allows for domain controllers, but it doesn't use PDCs and BDCs. All domain controllers in a domain are peers when the Active Directory is fully implemented. With this arrangement, changes to the security database can be made on any of the domain controllers. When using PDCs and BDCs, all changes to the security database must be made on the PDC (of which there can only be one in any particular domain). Additionally, those changes are propagated on a periodic basis out to the BDCs, which merely hold a copy of the security ...