Hi

For direct IO veritas has something called quickio on thier VsFs filesystem.
It involves creating a datafile with . and then making oracle use that.

You need to ask your sys admins if quickio is liscensed in your shop and only then you can use directIo.

google for veritas quick io.

http://seer.entsupport.symantec.com/docs/238079.htm

regards
Hrishy