periodically save current time to time-of-day hardware

[Dag-Erling Smørgrav]

Peter Jeremy <peterjeremy at acm.org> writes:
> At least some versions of Linux also save a RTC drift approximation
> and "last set" timestamp whenever the RTC is updated.  This allows the
> kernel to better set the system clock from the RTC at boot (ie, our
> inittodr()).  The downside is that this needs to store 8-16 bytes of
> state somewhere non-volatile.  Linux does this using an external
> program and a file - but finding a location for a regularly updated
> file that is read very early in the rc.d sequence might be problematic.

We already do something similar for entropy.

> that it _is_ updated.  This suggests that an alternative approach
> would be for adjtime() / ntp_adjtime() to directly call resettodr() if
> it's more than P minutes since resettodr() was last called.

...if we want something like Linux's eleven-minute-mode.

DES
-- 
Dag-Erling Smørgrav - des at des.no