Some people have complained lately about troubles with KA650 and
new kernels. I just upgraded my 3900 to the latest kernel and userland,
and I didn't encounter any problem with the new kernel; at least
it is still running. BUT:
If you're upgrading an existing system, be sure that you also 
change the /boot program! If you have a pre-march-98 boot program 
you must exchange it to a newer one, otherwise the kernel will
overwrite it when loading.
A fresh boot program (and kernel) can be found at multivac.ludd.luth.se.

-- Ragge