Specifications

18 Chapter 1 Directory Service Concepts

Processes no longer need to know how and where administrative data is stored. Open

Directory gets the data for them. If a process needs the location of a user’s home

directory, the process simply has Open Directory retrieve the information. Open

Directory finds the requested information and then returns it, insulating the process

from the details of how the information is stored. If you set up Open Directory to

access administrative data in several directory domains, Open Directory automatically

consults them as needed.

Some of the data stored in a directory domain is identical to data stored in UNIX

configuration files. For example, the crypt password, home directory location, real

name, user ID, and group ID—all stored in the user records of a directory domain—

have corresponding entries in the standard /etc/passwd file. However, a directory

domain stores much additional data to support functions that are unique to Mac OS X,

such as support for managing Mac OS X client computers.

Data Distribution

Another characteristic of UNIX configuration files is that the administrative data they

contain is available only to the computer on which they are stored. Each computer has

its own UNIX configuration files. With UNIX configuration files, each computer that

someone wants to use must have that person’s user account settings stored on it, and

each computer must store the account settings for every person who can use the

computer. To set up a computer’s network settings, the administrator needs to go to

the computer and directly enter the IP address and other information that identifies the

computer on the network.

Similarly, when user or network information needs to be changed in UNIX

configuration files, the administrator must make the changes on the computer where

the files reside. Some changes, such as network settings, require the administrator to

make the same changes on multiple computers. This approach becomes unwieldy as

networks grow in size and complexity.