FreeBSD/Solaris dual-boot, problems with time (ntpd)

[Chad J. Milios]

> On Jul 9, 2014, at 10:09 PM, Noel Hunt <noel.hunt at gmail.com> wrote:
> 
> I have a dual-boot machine, running ntpd in both OSes, but when
> I switch from one OS to the other the time is wildly out.
> 
> Can someone explain what is going on please?
> 
> Noel Hunt

Does your CMOS clock (aka BIOS) keep wallclock time or universal time? Either OS probably has the opposite idea.

If you never boot DOS/Windows, your BIOS should probably keep universal time.

Each OS has a way to let it know if that is or is not the case. In FreeBSD, if any file exists at /etc/wall_cmos_clock then the kernel treats the CMOS clock as the local time. If that file does not exist then the default is that the CMOS clock represents universal coordinated time (aka UTC). I don't use Solaris enough to tell you its equivalent procedure from memory but it has the same toggle in there somewhere.

(My knowledge of this is decades old. Can someone else confirm this is still the canonical way to set this preference in FreeBSD?)