Are the individual kernel models compatible?
The most recent version known as nanokernel has different semantics for the time_constant. When used with the old version 3 daemon, the PLL has a tendency to oscillate, because the damping is too low. When the old kernel implementation is used with the new version 4 daemon, the PLL is too stiff, causing a slow adjustment to frequency changes. When the new version 4 daemon has set the STA_NANO bit, the old version 3 daemon gets completely confused by nanoseconds which are believed to be microseconds. As it seems, the daemon does not clear STA_NANO during startup, so the only solution is to reboot or clear that flag by other means. Professor David L. Mills wrote: The old and new kernel code does use different time constant ranges. The current ntpd and API do understand and adjust accordingly. The old xntpd will probably be off by a factor of 16 in the time constant. That is absolutely certain to cause unstable operation. If you have an even older implementation, you probably can’t compil
