System unresponsive during HDD activity

[Bruno Wolff III]

On Fri, Sep 17, 2010 at 14:36:12 -0400,
  Robert Myers <rbmyersusa at gmail.com> wrote:
> 
> I've never thought that there was anything more complicated to this
> phenomenon than that keyboard and disk i/o are both serviced by
> interrupts.

That's not likely the problem. It's probably competing access to disk I/O
between the process displaying the desktop and other processes using disk I/O.