WTF with my computer clock?

The damned thing loses about 20 minutes/day and has so since the machine was new about 3 years ago.

My guess is that it isn't fixable, but maybe you have some ideas.

TIA.

Reply to
root
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Dunno what's causing it, but just put free utility "D4" on the machine, and set it to correct the time every 5 minutes.

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That way, it'll stay close enough all day. One of my workshop machines loses a coupla minutes a day. D4 runs in the background all the time, and keeps it right. Needs a connection to the 'net of course, but at least it will put the time right automatically as soon as you go online, if you don't have a permanent connection.

Arfa

Reply to
Arfa Daily

This is a chronic problem that seems to afflict all computers. I've never owned a machine whose clock didn't lose time.

Outside of resetting the clock manually, or running a utility that reads the time from some "correct" source and resets the clock, I know of no solution.

Reply to
William Sommerwerck

Well yes, but surely only a few seconds a day?

This machine checks and updates the time via the net and tells me when it does it. Usually approx twice a week and four seconds.

--
*If one synchronized swimmer drowns, do the rest have to drown too?

    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

Please don't call me surely.

I should have pointed out that 20 minutes a day is, indeed, unusual. But computer clocks are notoriously inaccurate. And I've never seen one that gained time.

Reply to
William Sommerwerck

Windows XP and Vista and Linux all have a built in clock sync with a time server. Figure out how to set it to update every 6 hours or less.

As far as the hardware is concerned it probably isn't fixable but it's not the end of the world.

Reply to
Meat Plow

I don't get it. It is just stupid to require an "always up" Internet connection for any kind of stability. Not to change the subject, B WTF with my Win 98 machine that keeps trying to connect to NTP servers? I can't find what process is doing that.

Reply to
JB

I suppose the unstupid thing would be to replace the hardware?

Besides, all CMOS clocks do not keep perfect time. Some worse than others. Why not use a network time sync if available. After all it's not a new idea. NTP has been around for ages.

connect to NTP servers? I can't find

There was no process imbedded in 98 for time sync (that I'm aware of). If it's a 3rd party application look for it in the startup folder or run msconfig for clues.

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Reply to
Meat Plow

"root" schreef in bericht news:h5ri4m$6vi$ snipped-for-privacy@news.albasani.net...

Well... Guess t's too late for guarantee.

A new battery sometimes solves the problem.

Find the clock/calender chip on your mainboard. If it has a DIP package, it can be replaced easily. (Hmm... That's to say I can. Don't know about your skills.) Some SMD-packages can also be replaced but less easily.

Buy, build a battery backup clock that can communicate via the serial port or an USB one. You will of course need some software too.

Ever saw a high accurate clock on a PCI-card. Don't remember where but still remember I considered it way too expensive.

petrus bitbyter

Reply to
petrus bitbyter

Well, that's: 20/1440 = 1.4% accuracy

Any particular maker, model, motherboard model?

I've seen the same problem on various machines over the years. On servers, the problem became sufficiently critical to impliment a fix. I measured the frequency of the common 14.31818 MHz crystal feeding the clock oscillator and found it to vary horribly with temperature. I replaced the crystal with a somewhat better packaged oscillator:

That reduced the drift to tolerable levels. Modern motherboards use different frequencies, but the same principle applies.

For a 14.31818Mhz oscillator to be off 1.4%, it would read about

14.5Mhz. Measure yours.

More difficult to fix are applications that steal clock cycles or beat up on the processor sufficiently that it misses interrupts. On my old Pentium III desktop, playing DVD videos was the worst culprit. I also found some CPU benchmark programs that intentionally made the processor very busy (and very hot) that ate CPU cycles. I can't offer any suggestions without knowing the hardware, the system, and the software mix.

There was also a problem with some old Dell machines, where the BIOS and the OS were fighting each other for control of the clock. There was a fix, but I'm too lazy to look for it.

One machine I worked with had a unique problem. When the machine went into standby, the clock would just stop. When it came out of standby, it would continue where it left off, losing the time it was in standby. It was fixed under warranty. I don't recall the vendor.

Oh yeah, check the button battery that backs up the clock. It might be dead or dying.

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
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Reply to
Jeff Liebermann

(snip)

Begin by finding out which of the two clocks is the bad guy.

The CMOS clock runs continuously, powered from the PC power supply when available and from the CMOS battery otherwise. During start-up the O/S reads this hardware clock and uses this value to initialize the software clock that is the date and time source until the next startup.

A bum oscillator or low CMOS battery will cause hardware clock errors and result in wrong-time initialization.

If the CPU misses servicing the clock interrupt or other bad stuff, the operating system's idea of time will suffer, but the hardware clock keeps right on ticking.

So, if you're losing time without a reboot, the CMOS is innocent and the O/S and CPU aren't doing the right dance. If the time is wrong from the gitgo, then the HW clock is the culprit.

Bryce

Reply to
Bryce

Ok. How about Kali? The goddess of time?

Think you're right there. So perhaps there's a reason for it. They're never going to be *that* accurate given the crystals they use.

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*The problem with the world is that everyone is a few drinks behind *

    Dave Plowman        dave@davenoise.co.uk           London SW
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Reply to
Dave Plowman (News)

Might want to skim over this;

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Battery could be bad from the manu. Not making enough voltage.

Xtal could be off freq.

Doubt it has anything to do with screwy IRQs, I've never seen this in

23 years around x86 hardware.
Reply to
Meat Plow

Good points. The computer loses time when it is running. It is the way the time is updated by the cpu/kernel. I am running linux.

Reply to
root

This suggests that one of several things is happening.

One is that some device driver in your system is disabling interrupt processing for a period longer than the kernel's "tick" time value (usually 1 millisecond, in modern Linux kernels). I've seen this happen with some disk and network drivers, particularly under periods of high loading. Some video-card drivers might also have this problem, particularly when doing highly-intensive rendering.

Another possibility is that your system is configured to use a "high resolution timer" system to keep track of the time... i.e. a timer within the CPU itself which ticks along at the basic CPU clock rate, or some sub-multiple of it. If the motherboard / BIOS / kernel "thinks" that the CPU is running at a certain clock rate, but the actual oscillator is a bit slow, then the high-resolution timer will be running at a rate slower than the kernel's computations expect, and the clock will drift.

You may be able to resolve the problem by using the NTP daemon (available in most distributions). It has two benefits:

- It can set, and resynchonize the system clock via periodic queries of highly-stable time servers, via the Internet. This gives you a very reliable time-sync to start with.

- It can calculate the amount of "drift" that your system's local clock has (by comparing the system clock-run rate against the rate deduced by querying NTP servers), and can then instruct the kernel to compensate for this drift (i.e. "tweaking" the kernel's own clock-update algorithm). This compensation helps keep the clock correct, in between the larger adjustements that the NTP daemon makes when it queries Internet time servers.

--
Dave Platt                                    AE6EO
Friends of Jade Warrior home page:  http://www.radagast.org/jade-warrior
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Reply to
Dave Platt

Well, hello, Kali!

Reply to
William Sommerwerck

Since you are on this newsgroup, fixing it should be easy. All it requires is a little soldering. I just checked two fairly modern motherboards and located the crystal that is associated with the CMOS clock. Look for a small cylinder lying flat to the board in the neightborhood of the CMOS battery. That is the crystal that controls the clock. The error you are seeing is well outside the normal tolerances for a 'good' (or even a cheap) crystal. Replace it.

If you want high accuracy, it would be necessary to adjust the frequency by adjusting the parallel capacitor, but normally you should have an error of less than a minute a week with an uncalibrated crystal.

PlainBill

Reply to
PlainBill47

I think they are similar to watch crystals and are susceptible to vibration, make sure its glued down.

Reply to
George Jetson

Thanks for the advice Dave, I started ntpd and will see how that works.

Reply to
root

That will make it vibrate just as much as the mobo; if it's just hanging there by its leads, it may well vibrate less.

Isaac

Reply to
isw

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