Let me say up front that I am far from being a "standard guru";
having said that, here's what I know:
Solaris does AIO in kernel on raw devices AND filesystems. In
2.4 you need to install it as a patch, 2.5+ should have that
in the vanilla distribution.
Actually it's the only OS I have seen where Oracle7 supports
asynchronous reads and writes on the filesystem.
SunOS, AIX (up to 4.1.5) and HP-UX (up to 10.20) only do AIO
on raw block device. Don't know for sure about other platforms
or later releases of AIX and HP-UX.
Ciao,
--alessandro <asuardi@uninetcom.it> <asuardi@it.oracle.com>
Linux-i386 kernel-2.1.36 libc-5.4.23 gcc-2.7.2.1 binutils-2.7.0.9