Re: Why touch the CMOS clock?

Thomas Quinot (thomas@cuivre.fdn.fr)
8 May 1996 20:59:04 GMT


=3D?iso-8859-1?Q?Johan Myr=3DE9en?=3D (jem@vistacom.fi) =E9crit :

> 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 doe=
s its
> timekeeping using the timer interrupt.

This is essentially right. But the kernel can also do elaborate time-ke=
eping
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.

--=20
Thomas.Quinot@Cuivre.FdN.FR <URL:http://Web.FdN.FR/~tquinot=
/>