Directory Server 6.3 is provided in two distributions:
Java Enterprise System distribution. This distribution takes the form of operating system-specific packages, such as pkg for Solaris and rpm for Linux.
Compressed archive (zip) distribution.
There are two major differences between these two distributions:
Installation from zip can be done anywhere on the system and as a non-root user. The Java Enterprise System distribution requires installation as a super user. It is also more difficult from an automated deployment perspective to install the packages anywhere but in the default location.
The zip distribution can be installed as many times as required and multiple distinct versions of the same product can coexist on a single operating system instance. This is not true for the Java Enterprise System distribution. The new version of certain shared component packages required by Directory Server are incompatible with the previous version of these packages. When you migrate to the new version of Directory Server using the Java Enterprise System distribution, the old Directory Server version will no longer run on that machine.
Depending on your environment and the specific requirements of your organization, select the appropriate packaging format.