Quoting "Alan J. Flavell" <[log in to unmask]>:
> Perhaps I need a "magic sysreq". These are areas I haven't really
> explored before. Haven't done kernel hacking / interrupt handling
> stuff since IBM VM/370 or so ;-)
>
On that subject, Simon Trimmer gave a very good talk to my LUG a few
years ago. Probably a bit out of date now, but I've found it useful.
http://urbanmyth.org/linux/oops/slides.html