2.5.1 Overview of Oracle Base Directories
The Oracle base directory is the location where Oracle software and configuration files are stored.
By default, Oracle Universal Installer (OUI) installs the Oracle Database software binary files by version and Oracle Home Name in a subdirectory of the Oracle base directory. An Oracle base directory can be used for multiple installations of software by a given installation owner. A separate Oracle base directory is created for each Oracle Home user you specify during Oracle Database software installation.
The Oracle Home User has complete control over the Oracle base directory. For reasons of security, different Windows User Accounts used as Oracle Home Users for different Oracle home directories are not allowed to share the same Oracle base directory.
The default Oracle base path contains the Oracle Home User name if an Oracle Home User is specified during installation of the Oracle Database software. In a default Windows installation, the Oracle base directory appears as follows, where username is the Oracle Installation user if you choose Windows Built-in Account as the Oracle Home User, or it is the Oracle Home user if one is specified:
DRIVE_LETTER:\app\username
Caution:
Do not install older versions of Oracle Databases that share the same Oracle base directory. During installation of older releases, the ACLs are reset on Oracle base, so the newer release services may not be able to access the Oracle base directory and files.Parent topic: Overview of Installation Directories for Oracle RAC