An initial installation overwrites the system's disk with the new version of the Solaris operating environment. If your system is not running the Solaris operating environment, you must perform an initial installation.
If the system is already running the Solaris operating environment, you can choose to perform an initial installation. If you want to preserve any local modifications, before you install, you must back up the local modifications. After you complete the installation, you can restore the local modifications.
You can use any of the Solaris installation methods to perform an initial installation. For detailed information about the different Solaris installation methods, refer to Chapter 3, Choosing a Solaris Installation Method (Overview).