Clock not keeping correct time between reboots

[luikki]

thanks blackbird!

surely my problem is different. but then, i'm not sure if it is not related to pclinuxos 2010...
0-93, 2007 and 2009 never had this behavior ...  using or not the ntp servers...
and, again, a different linux flavor doesn't produce this effect... it shows the right software time and bios clock remains correct.
i can live with it... but i like things to perform right.

[Was_Just19]

Maybe ntpd is not ticked to start in System Services?

That's possible of course, but it wouldn't really explain the problem: ntpd keeps the system clock synchronized to a time server, while in this case it appears to be the hardware clock that refuses to be synchronized to the system clock....

Oh well I have to admit to being confused so   

I don't know exactly what you mean by systen Vs hardware clocks ......  confusion due to hwclock command I guess which does not change the BIOS clock that I am aware of.

From what little I knew - or thought I knew - about these things I regarded it like this .....

BIOS clock ......  set it manually to local time.

System clock ... the clock of the OS. Normally shows the BIOS clock by default but can be changed. Adjustable in PCC, selecting a different time zone will show an offset time, can be kept in line by using NTP, or indeed can be adjusted by using the command hwclock.
It is my impression that neither hwclock nor NTP make any change to the BIOS clock.

So, if the BIOS clock is correct, and a repeatable 5 hour offset occurs, it seems most likely that the 5 hours is a time-zone offset being applied.


But it seems I am not correctly understanding the clocks and how they interact   

[Galaxar]

Ok, just read all the posts! wow.  i went to bed with 6 replies and come back with 15!   

Yes, my timezone is setting to Chicago, which is correct.  I tried setting it to Denver, using UTC, and then reboot and then the time was off by 6 hours.  Now, something interesting occurred this morning.  I went into PCC to set my time.  I went into the settings for my time and date and then pressed the OK button.  After a few seconds, a message popped up saying that it couldn't connect to my time server (I'm using the North American pool server), but my time was corrected!  Any ideas?

Oh, and the nptd service is enabled to start at boot.  Always was.


Galaxar

[Bald Brick]

Oh well I have to admit to being confused so  

I don't know exactly what you mean by systen Vs hardware clocks ......  confusion due to hwclock command I guess which does not change the BIOS clock that I am aware of.

Try it with the --systohc option and it will. (Or with the -w option.)

The hardware clock is the same as the BIOS clock -- the only clock running when the computer is powered down. A.k.a. the CMOS clock and the Real Time Clock.

From what little I knew - or thought I knew - about these things I regarded it like this .....

BIOS clock ......  set it manually to local time.

Or programmatically in any number of ways, including using the command  hwclock --systohc.

And why set it to local time? That's a Windows thing.

System clock ... the clock of the OS. Normally shows the BIOS clock by default but can be changed.

It's normally synchronized to the BIOS (hardware) clock at boot, and if the BIOS clock is set to UTC, the system clock is adjusted according to your time zone. After that the system clock keeps time using any of several kernel clock sources, but it does not continuously show the time of the BIOS clock. The BIOS clock is just used to set the system clock.

Adjustable in PCC, selecting a different time zone will show an offset time, can be kept in line by using NTP, or indeed can be adjusted by using the command hwclock .

Yes.

It is my impression that neither hwclock nor NTP make any change to the BIOS clock.

The ntp daemon seems to do it only indirectly. On the other hand, in PCLinuxOS the hwclock command sets the BIOS clock directly in /etc/rc.d/init.d/halt.

So, if the BIOS clock is correct, and a repeatable 5 hour offset occurs, it seems most likely that the 5 hours is a time-zone offset being applied.

Yes -- if it weren't for the error message Galaxar reported. And the fact that the BIOS clock doesn't seem to be correct.

But it seems I am not correctly understanding the clocks and how they interact  

Who is?  

[Galaxar]

Actually, my BIOS clock is correct.  Strange, huh?  Also, would this have anything to do with ACPI?  I can only use acpi=ht or acpi=off on this laptop.  if I try to use acpi=on or acpi=force, it locks up during bootup.

Galaxar

[Bald Brick]

Actually, my BIOS clock is correct.

But is it set to local time or to UTC? (We seem to be getting back to my very first question.)

[Galaxar]

local time. it's 1:02 pm here now, so it'll say 13:02.

Galaxar

[Bald Brick]

local time. it's 1:02 pm here now, so it'll say 13:02.

Then UTC should be set to false in /etc/sysconfig/clock. (You can set it from the GUI, but check the file anyway.)

[Galaxar]

Ok, did that, rebooted.  same result.  5 hours back.  *sigh*

Galaxar

[Bald Brick]

Ok, did that, rebooted.  same result.  5 hours back.  *sigh*

Which makes one suspect that JohnBoy is correct after all. The difference between GMT and US Central Standard Time is six hours. The difference between GMT and your Daylight-Saving Time is five hours.
(Which still doesn't explain why your BIOS clock can't be set at shutdown.)

How do you know that your BIOS clock is correct?

[Galaxar]

Which makes one suspect that JohnBoy is correct after all. The difference between GMT and US Central Standard Time is six hours. The difference between GMT and your Daylight-Saving Time is five hours.

Exactly what i am thinking.

How do you know that your BIOS clock is correct?

Because I checked it in the BIOS screen.   

Galaxar

[Was_Just19]

From what little I knew - or thought I knew - about these things I regarded it like this .....

BIOS clock ......  set it manually to local time.

Or programmatically in any number of ways, including using the command  hwclock --systohc.

And why set it to local time? That's a Windows thing.

  .....  maybe because all clocks in my house are set to local time      indeed why set it to anything else? 

The hwclock command name is a bit of a misnomer it seems to me.
Using hwclock -r  or indeed hwclock in PCLOS seems to return the system time.
In PCC I can change the time and the time reported by hwclock reports the change.
If the BIOS clock is then checked it reports the time originally set ..  it has not been changed.
So using the GUI provided in PCC does not appear to change the BIOS clock, but the system time.
Rebooting I think retains the system time set rather than syncing to the BIOS clock again.

Still trying to get rid of my confusion   

[luikki]

and i'm even more confused...   (and frustrated ... it's no big deal but something is not right...)
here,  bios clock is always one hour behind, login screen clock is one hour fast and software clock is correct for my local time...
hwclock has a mind of its  own. sometimes shows the correct local/bios time... sometimes shows one hour fast...
once again: it only happens with 2010 b2, minime 2010 and 2010 final...

[Bald Brick]

Using hwclock -r  or indeed hwclock in PCLOS seems to return the system time.

Well, according to the documentation hwclock -r and hwclock -show should "read the Hardware Clock and print the time on Standard Output" -- but "in local time, even if you keep your Hardware Clock in Coordinated Universal Time". And that's what the commands seem to do here.

When your computer has been running for a few hours, try the commands

Code: [Select]

hwclock -r && dateThe first one should give you the BIOS time, the second the system time.

Then run

Code: [Select]

hwclock -w and repeat the first two commands.

In PCC I can change the time and the time reported by hwclock reports the change.

Here too. I don't know what drakclock actually changes, but it seems to have an effect on both system time and hardware time. (And on my ntp daemon, which just got a mild nervous breakdown from all my time changes.)

If the BIOS clock is then checked it reports the time originally set ..  it has not been changed.

This I'll have to check tomorrow. I don't want to reboot tonight, and you obviously wouldn't trust whatever hwclock reports.

So using the GUI provided in PCC does not appear to change the BIOS clock, but the system time.
Rebooting I think retains the system time set rather than syncing to the BIOS clock again.

How would the system time be retained after a shutdown if it isn't written to the BIOS clock and restored on reboot?

[Bald Brick]

and i'm even more confused...   (and frustrated ... it's no big deal but something is not right...)
here,  bios clock is always one hour behind, login screen clock is one hour fast and software clock is correct for my local time...
hwclock has a mind of its  own. sometimes shows the correct local/bios time... sometimes shows one hour fast...
once again: it only happens with 2010 b2, minime 2010 and 2010 final...

Precisely what does your /etc/sysconfig/clock look like? (I should probably have asked Galaxar the same question....)