> Hi,
> 
> today tried the latest kernel from the autobuild directory and found,
> that every 20 seconds the system hangs completely for about 1 second,
> and the harddisk is accessed. Does anybody know what is the reason for that?
> 
> Normally I use the kernel sa110-4958. There also every 20 Seconds the
> harddisk is accessed for about 1 second, but the system still reacts during
> that time.

Every 30 seconds or so, RiscBSD makes certain that the contents of any
harddiscs mounted are up to date by running sync.  

A recent bug-fix to sync ended up with it doing the advertised
synchronising, but at the expense of a large amount of StrongARM
cache-cleaning. 

The cache-cleaning is CPU intensive, causing the system to 'freeze' for a
second or two, every 30 seconds.

There's rumours of an overhaul of bits of the kernel code to help with
this, but in the meantime you either put up with it, not run sync, or use
the hack advertised previously in the list (it'll be in Olly's archive,
somewhere - search for 'HACK HACK HACK' ;-), putting the future of your
harddisc's contents on the line...

Hope this helps,

Dan