For both modes of installation, information for Reporting Services components is stored in configuration files and the registry. During setup the configuration files are copied to the following locations:
C:\Program Files\Microsoft SQL Server\MSRS11.MSSQLSERVER
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\15\WebServices\Reporting
Follow the link http://msdn.microsoft.com/en-us/library/ms155866.aspx for details.
The Report Server Windows Service is an orchestrated set of applications that run in a single process using a single account with access to a single Report Server database with a set of configuration files listed here: