Re: Time is going very much off all the time

Unruh wrote:

Darrell Stec <darrell_stec@xxxxxxxxxxxxxxxxxx> writes:

houghi wrote:

Darrell Stec wrote:
My time is going off all the time since a few weeks. Not sure when it
started, but I now need to do a netdate every 4 hours and the time
difference is between 1 or 2 seconds up to 5 minutes.

Anybody an idea what might be causing this?

houghi

I had a similar problem. What fixed it was to set the BIOS clock to a
slightly different time, boot Linux. Reboot and set the BIOS to the
proper time and then use the time feature in OpenSuse to set it to the
same time. I don't know why that fixed the problem.

Will try that.

If your clock is slow, you might change the backup battery on the
motherboard.

The PC is not turned off, so the battery could not be there, for all I
care.

houghi

Depending upon the motherboard the battery may run the clock all the time
and is continually recharged. But if old enough it takes less and less a
charge. Since the charging circuit take a few milli or nanoseconds to
recharge the depleting battery you will loose that time. The effect is
cumulative so eventually the clock will loose more and more time.


NONONO.

YESYESYESYES.

There are three different clocks on the motherboard.


Gee thanks for telling me this. I've been around computers for a long time.
In fact I built my first three as in designed, etched, drilled and soldered
the compontents.

The RTC,
which is run by battery andis ONLY used by the system at bootup to set the
system cloock.

And if it is wrong everything goes downhill from there. I did not GUESS at
my recommendation. I used it to fix a real problem with my computer time
drifting off, as much as 8 minutes a day. My time is now accurate and is
almost to the second in agreement with my cell phone and Palm Pilot. It
wasn't before.

Doing what I recommended sets the RTC and the software clock to the same
point in time. That's why it worked in my case.

It is the only thing runby the onboard battery, and is never
used during running linux after startup. Then there are the timer
interrupts which are set to occur once every 10ms.

And some interrupts are and always have been read every eighteenth of a
second. The RTC is capable of issuing periodic interrupts on IRQ 8 at
frequencies ranging between 2 Hz and 8,192 Hz. It can also be programmed to
activate the IRQ 8 line when the RTC reaches a specific value, thus working
as an alarm clock.


These are run from the
main bus freq crystal which is run from mains power.

What are you calling mains power. Here in the US that means the 120 volts
AC.

If it does not work,
your computer does not work. Finally ther is the main processor frequency
whichi is used by Linux to count the subdivisions between 10ms. (to
1microsec). Again it does not work only if your cou does not work.(eg in
suspends).

--
Later,
Darrell Stec darstec@xxxxxxxxxx

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