Measuring IOPS of 9i database

Hi,

we are trying to calculate IOPS for our production database running 9i RAC (2 node) using the following query

The query runs fine on 10g but gives "0" data when run on 9i

Can someone please kindly let us know as to how we can measure the IOPS of 9i database?

 SELECT 'Number of Small Reads :'||

       sum(decode(name,'physical read total IO requests',value,0)-
	
           decode(name,'physical read total multi block requests',value,0)),
	
       'Number of Small Writes:'|| 
	
       sum(decode(name,'physical write total IO requests',value,0)-
	
           decode(name,'physical write total multi block requests',value,0)),
	
       'Number of Large Reads :'||