How to disable the OS cache?

[Roberto Figueira Santos Filho]

Hello!

I'm working with indexing methods, doing some perfomance comparisons. 
Most of them are to index high dimensional vectors (R-Tree, SR-Tree, 
TV-Tree...). The methods must support second storage management. My 
problem is that I need to do some tests (inserting and querying data) 
and compare the CPU time for each method, but I don't know how to 
disable the caching on Linux. I mean, I need to disable the cache 
management so the time for each method won't be disturbed by the OS.

Does any one knows if is it possible to disable the cache for a single 
process? Or, in the worst case, for the entire OS? Or even, if there is 
a very small version of Linux that can be adjusted to work without caching?

Thanks in advance.

Roberto Figueira Santos Filho