Re: Q for the standards gurus...

David Williams (
Wed, 30 Apr 1997 19:58:04 +0100

In message <>,
Mike Jagdis <> writes
>I was thinking about AIO since some people say it absolutely
>essential for high end database engines. It looks relatively
>easy to do this in a very lightweight (i.e. no clone process)
>way - but only for directly accessed block devices. It's only
>when we have to go through the filesystem layers that we have
>to have a process context to do wait_on_buffers in or rewrite
>the filesystems.
> Question: I know wossisname, Gallmeister, gives AIO examples
>of AIO on ordinary files. I also know that SCO only does AIO
>on raw devices. What do other systems do? What is actually
>required by the standards? Would everyone or anyone be happy
>with AIO on block devices only?
Yes - Informix only uses KAIO aghainst raw devices anyway..
probably because it's only available on raw devices on most

> Mike

David Williams