The host driver file names identify which version of Linux they support and have this format:
OLversionuupdate-5.0.8.tar.gz
Where:
version is the Linux major version release number.
update is the Linux version update number.
For example:
OL5u10-5.0.8.tar.gz is for Oracle Linux/RHEL 5 Update 10
OL6u5-5.0.8.tar.gz is for Oracle Linux/RHEL 6 Update 5