On Sat, Feb 06, 1999 at 05:06:36PM +0000, Mario Kemper wrote:
> In article <19990206185149.A15690@pyy.jmp.fi>,
> 	Jukka Marin <jmarin@pyy.jmp.fi> writes:
> > 
> > However, the disk starts again every 30 seconds - thanks to update.
> > 
> > Why? :-)
> > 
> man update

Yes, I know what update is and why it does what it does.  What I didn't know
was why anything was "flushed to disk" when no data were being written to any
file.  The answer is that sync() updates the disk superblock timestamps
even when no buffers are actually flushed to disk.  So, as far as I
understand, using async mount is currently the only way to keep the disk
sleeping.

  -jm