Source upgrade from 5.5 to 6.X not safe?

[[LoN]Kamikaze]

> In general, is it possible that the installkernel did /not/ complete
> correctly before I shut down?  Is it ever possible that the machine could
> get put into an indeterminate state when doing installkernel on a running
> machine?  HP-UX used to behave horribly when a binary got clobbered for a
> process that was running, but I have no idea how FreeBSD copes with
> changing disk images of a running process.

If a binary/library that is currently used gets removed/replaced, it will be
copied to memory. The process will not even recognize this. Only restarting
the process will remove the old version from memory and cause the new one to
be used. I thought every OS did it like that, so I'm surprised that there are
systems causing problems in this case.

For the kernel likewise. The kernel and the loaded modules remain in memory,
but of course you cannot load the newly built modules until you have rebooted
with the new kernel (because there's no other way to restart a kernel).