Oracle ORAchk and Oracle EXAchk display this message if the tools are not able to detect the operating system.
If Oracle ORAchk and Oracle EXAchk are not able to detect the operating system, then the tools prompt:
Data needed for the derived platform could not be found
Improperly detecting an unsupported platform
RAT_OSenvironment variable to the correct operating system:
$ export RAT_OS=platform