Sorting processes by disk usage?

[Try KDE <trykde@rogers.com>]

Hi,

Here is  the  situation: the hard drive LED is flashing every 2 seconds, 
I don't  which process is causing it, or if it's a kernel thread doing 
swapping or something. So how can I find out? "top" doesn't seem to 
answer that question. (Note that a disk intensive program is not 
neccesarrily CPU intensive).

Thanks,
-tk