Re: How to use /etc/adjtime

[John Hasler <john@sugarbit.com>]

David writes:
> With chrony, you can monitor the RTC over time and adjust the system
> clock in accordance with its drift rate at boot time, without
> correcting the RTC itself, or you can actually set the RTC from the
> system clock periodically.

That leads to the probelem that started this thread: system time being
set incorrectly at boot and then stepped later.


> The particular problem at shutdown is that there were/are systems, as
> you described, that write the system time to the RTC without
> necessarily regarding how you might be running the clock otherwise.
> That alteration is unknowable for chrony when it restarts after
> booting.

Obviously you must make sure that only one process ever writes to the
RTC.

Actually you need never write to the RTC at all: just track its offset
and drift rate.  That would require hacking the boot process to make
sure only your code ever reads it, though.
-- 
John Hasler 
john@sugarbit.com
Elmwood, WI USA