> > My question is: Why does the kernel have to update the RTC? It is my
> > understanding that the kernel only reads the RTC at boot time and does its
> > timekeeping using the timer interrupt.
>
> This is essentially right. But the kernel can also do elaborate time-keeping
> using external clocks (eg. radio clocks) or network services (NTP...),
> which renders the kernel time *much* more precise than the RTC. The
> kernel therefore needs to update the RTC in order to limit its drift.
My point was: does it _really_ need to update the RTC? The kernel time
functions (no matter how they are syncronized) do not need, nor use the
RTC time, except when the machine is booted.
Johan Myreen
jem@iki.fi