Why oracle recommand using file system to store data?

[Andy Beal]

9.2.0.1 - The shipping release called 9iR2 will use filesystems. If you purchase online JFS from HP you have options to disable the Unix buffer cache on certain filesystems. As far as reasons not to go with RAW devices, the biggie has been stated, inevitably someone will not understand it in the future and possibly ruin your db. If your trying to run 24x7, you'll never really be able to do anything with the dbf files anyway, except maybe look at em.