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Directory Concepts

Directory Services have been around for several years, but mostly in the enterprise environment. A Directory Service allows you to easily manage your network resources. Simply put, a Directory is a database of objects that represent network resources, such as network users, servers, printers, print queues, and applications. A Directory can be described as a hierarchal tree. Typically a Directory is stored as a set of database files on a server. A NetWare server stores these files on volume SYS. If no file system volumes are present, the server stores the Directory database files in an installation subdirectory. Typically a Directory can be replicated on multiple servers.

Directory Trees

Directories use trees to keep track of information. A Directory tree can be thought of as a distributed database that contains directory information about objects. That is, the database contains objects and the attributes, or properties, that describe those objects. Each Directory tree maintains its own database of objects. Because it is a distributed database, the database is usually contained on more than one server.

The information in a Directory tree does not describe the physical layout of the network. It usually describes the logical organization of the business. The Directory tree is usually organized into subtrees that reflect the different departments and units in an organization. In turn, those subtrees contain the resources within the different departments.

The Directory tree is made up of objects. These objects represent network entities and are of two basic types: leaf objects and container objects. In the tree representation, container objects can hold leaf objects and other container objects. Container objects are Country objects, Organization objects, or Organizational Unit objects. Leaf objects usually represent a network resource such as a user or a printer and can hold no other object.

If, for example, Acme used the Country Organizational Unit to organize its tree by country, the country organizational unit would be located between the root and the Organization objects.

An object's name context is a list of these containers between the object and [Root]. This context, or name, describes its position in the NDS tree.