Oracle Home Directories The Oracle Installer places most Oracle products into a common location, known as the Oracle home. The Installer prompts the user for this location at setup time. Oracle Homes Types The Oracle Installer supports three types of Oracle Homes: Stand-alone This home contains products meant to be accessed by a single user. It is created when the user runs the Installer in stand-alone mode (ie. when the user runs the executable, ORAINST.EXE) OCSM Host This home contains products meant to be accessed by multiple users as specified by Oracle Client Software Management (OCSM). It is created on the OCSM host machine when the administrator runs the Installer to install shareable products. OCSM Client This home contains product files meant to be accessed by a OCSM client. It is created on an OCSM client by running the Oracle Client Software Agent (SHARAGT.EXE) which runs the installer in configuration mode. Note: - The OCSM Host type and the OCSM Client types of Oracle homes are only available for Windows 3.1 products. Please refer to your installation guide for more information on setting up OCSM. - Oracle homes cannot be deleted. The user can only change the type of an existing Oracle home. Multiple Oracle Home Support The Installer allows the user to maintain more than one Oracle home per machine and to switch homes. This feature enables the user to do the following: - Test product installations without affecting working Oracle homes. - Maintain different versions of the same product in different homes - Evaluate a new version of a product without affecting the installation of a currently working version of the product. - Allow OCSM clients to access and share products from more than one OCSM host. - Allow OCSM clients to maintain stand-alone installations of products not available via accessible OCSM hosts. Note: - Only products installed in the currently active Oracle home can be used at a time. Switching Oracle Homes To switch between homes, do one of the following: - Double-click on the "Switch Homes" icon in Oracle's main program group. The Installer displays a dialog listing the available Oracle homes and their types. Select the Oracle home you want to switch to and click on OK. Click on Exit to exit the Installer. - Run the Oracle Installer from your distribution media. The "Oracle Installation Settings" dialog provides a pull-down list of the available Oracle homes. Choose the home to switch to and click on OK. Click on exit to exit the Installer. Note: For Windows 3.1 and Windows 95, the path variable in autoexec.bat is modified when the user switches Oracle homes. The system needs to be rebooted for these changes to take effect. Conflicting Oracle Home Types An Oracle home can be stand-alone, OCSM host, or OCSM client, corresponding to the Installer mode that creates it, namely stand-alone, shared, or configuration. Whenever you switch to an existing home and there is a conflict between its type and the current installer mode, the installer brings up a dialog which lets you either change the installer mode to match the type of the chosen home or change the type of the Oracle home to match the current installer mode. We recommend changing the Installer mode. Change the Oracle home type only when you want to delete the existing home to create a new one, since installed products in the home will become unusable. Backward Compatibility If you run the multiple Oracle home capable Installer (version 3.1.4 or later) on an older installation, the new Installer gracefully upgrades the previous installation without losing any configuration information or installed products. The modified environment still works with older versions of the Installer; that is, you can still run an older Installer to install new products over the new setup without affecting multiple Oracle homes settings. Multiple Oracle Home Implementation Windows 16 bit Oracle homes: Every Oracle home maintains its own ORACLE.INI file. The Oracle section of the WIN.INI file keeps track of every known Oracle home, using the following variable binding for each home: ORA_CONFIG= The ordinal number is incremented for every new Oracle home. The ora_config variable (without the suffix) in the Oracle section of WIN.INI points to the location of the ORACLE.INI of the currently active Oracle home. Note: - With versions of the Installer earlier than 3.1.4, the ORACLE.INI was maintained in the SYSTEM directory. When you upgrade an old installation to support multiple Oracle homes, the Installer moves the ORACLE.INI file to its proper Oracle home directory. When switching Oracle homes, the Installer does the following: 1. Updates the ora_config variable in the Oracle section of WIN.INI to point to the ORACLE.INI of the chosen home. 2. Deletes all icons in the desktop corresponding to the previous Oracle home and restores the desktop corresponding to the current Oracle home. 3. Changes the Oracle home path in system environment to the new path. Windows 95 Oracle homes: In the registry, the \HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\ subkey contains information about the currently active Oracle home. The Installer creates separate entries of the form "ORACLE" for every known Oracle home under the ..\ORACLE\ORACLE_HOMES subkey. The ordinal number is incremented for every new Oracle home. When switching Oracle homes, the Installer does the following: 1. Updates the ORACLE entry in the registry to correspond to the chosen Oracle home. 2. Deletes all icons in the desktop corresponding to the previous Oracle home and restores the desktop corresponding to the current Oracle home. 3. Changes the Oracle home path in system environment to the new path. Restoring Miscellaneous Keys Some applications might store information outside the SOFTWARE\ORACLE subkey. Such applications use win32_register_key() to register these keys with the Installer. This enables the Installer to restore or remove these keys when you switch into or out of an Oracle home.