Mailinglist Archive: opensuse (4547 mails)

["Carlos E. R." <robin1.listas@xxxxxxxxxx>]

The Tuesday 2004-05-04 at 21:56 +0200, Anders Johansson wrote:

> The RTC (real time clock) is on the CMOS chip and powered by its battery, as
> far as I understand.

Correct.

> Also, from what I can tell, the CMOS clock is accessed
> quite frequently as part of the timer interrupt.

No, it is not accessed at all, for many reasons. One, it is a very slow
access. Two, the CPU maintains its own clock, and doesn't need it.

Linux does not access it at all, except during the boot sequence. Windows
accesses it every time you change the hour in the system, to keep both
synchronized.

Read my howto, it is documented there, and my sources for so saying.

> I'm not exactly sure what
> effect a low or dead battery will have on those, but it can't be good

Nothing at all after boot, while the system is running.

And some (or all) of those chips are also powered from the board 5 Vcc
while powered up.

-- 
Cheers,
       Carlos Robinson