I/O on AIX

OS : AIX 4.3.3
Oracle server : 8.1.7.1

1.
I wonder if anyone already has use LIST I/O ( by setting _enable_list_io=TRUE ) on the above software configuration.

If so, was it a performance gain or loss ??

2.
Does anyone know if AIX supports Kernelized Async_IO ?
If so, how do we configure it ?

Was it a performance gain or loss ??

thanks
Gert