> For filesystems, obviously the sync(2) family need to force data
> all the way to non-volatile memory.  That's the whole purpose of
> the calls.
> 
> For non-filesystem things (e.g. databases using raw partitions)
> things aren't quite as simple.  Maybe add an argument to write(2)?
> An ioctl to force the device into non-caching mode?  Either way
> things are ugly and assorted nasty issues come up.

fsync() on the descriptor open to the device, perhaps?

					- Bill