Did you ever try to bring down a real Tandem machine ?
You can literally shoot the machine with a gun without
bringing it down.
Or swap memory banks or CPUs or disk subsystems or.......
The developers of those machines go crazy when they are working
on the OS and have forgotten to disable the backup batteries for
the CPUs. If you disable one CPU the other CPUs will immediately
reboot it before you are able to disable the others.... :-)
The need for a JFS goes down dramatically if you can't bring down the
machine, but we are talking here about machines that you don't even think
about below $100k (for the smallest possible configuration of course).
Mike