The data source scanner queries your machine for data sources that can be monitored. This eliminates the need for you to do the search manually. The automatic detection might not find every possible data source, since it is based on a configuration that closely mimics the predefined data sources. It goes through the list of the predefined data sources and checks for their availability.
For example: The data source scanner queries your machine for the number of processors, the number of network interfaces, the number of database instances, and how these components can be monitored.
Details such as the platform on which your system runs (NT, AIX, or Linux) do not matter because the monitored components, such as CPU or hard disk utilization, are platform-independent.