To identify the Oracle® system ID (SID) and home directory, use one of the following procedures, based on the OS running on the Oracle Database Server.
On Windows®, the SID and Oracle® Home can be determined from the Registry.
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 1   | 
 Start the Registry Editor on the Oracle Database Server.  | 
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 b   | 
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 3   | 
 Open the folder entitled “KEY_<Oracle_Home>” that represents the target installation of Oracle to list the registry items in the frame on the right.  | 
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 4   | 
 In the Name column, locate the following items, and make note of the associated entry in the Data column:  | 
On Linux® and UNIX®, you can use the “oratab” file to identify the SID and Oracle® Home.
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 1   | 
 Open the “oratab” file by issuing the following command in a terminal window:  | 
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 2   | 
 In the “oratab” file, note the application information.  | 
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 “PROD” is the ORACLE_SID  | 
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 “/u03/app/oracle/product/10.2.0/db_1” is the ORACLE_HOME  | 
As discussed in Choosing the location for the RMAN repository, for an RMAN backup strategy you must first choose a location for the RMAN repository. By default, this repository is maintained in the Control File. However, for larger or more mission-critical databases, create a Recovery Catalog database that can store a much longer history than the Control File.