Q for the standards gurus...

Mike Jagdis (mike@roan.co.uk)
Wed, 30 Apr 1997 11:09:17 +0100 (GMT/BST)

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?


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