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Weird PC Clock Behavior?
cybercyst asks: "I've been having a problem with this for quite some time, and thought it was just me -- until two good friends of mine experienced the same problem. What we are experiencing is best described as a time-skew: our system time is apparently jumping forward an hour, and then returning to normal. It repeats this multiple times, and as far as I can tell only a reboot is any sort of remedy for this, albeit a temporary one. As you can imagine this causes all sorts of problems (under windows managers xscreensaver is always popping up -- in fact as I wrote this, the screensaver has come on over 10 times, negative fps in OpenGL programs, extremely large ping times, and so forth)."
"Friend A runs an Athlon system on a Soyo Dragon motherboard, I'm running a K6-2 450Mhz CPU on an older Epox motherboard. We are both running Slackware 8.0 with kernel 2.4.17, but Friend B runs nothing but Red Hat, and kernel 2.4.2-2.
I have personally tried many things to get this fixed permanently, including setting the time with 'date -s; hwclock --hctosys; hwclock --systohc' the BIOS is set to the right time that doesn't seems to help! So, I'm asking Slashdot, Has anyone out there encountered a similar problem, and if they have, have you been able to fix it?"
[from http://www.debian.org/doc/manuals/system-administr ator/ch-sysadmin-time.html]:
Computers have a clock to keep time. Usually there is a hardware clock with battery backup to keep time when the computer is off. The operating system (for example Linux) runs its own clock, and from this clock comes the time shown by commands such as date in Linux and time in DOS.
The hardware clock is usually accurate enough, provided that the battery has not run out. If the time shown by the computer when you turn it on is wrong by several months or years, it is worth checking if the battery is still usable.
The "software" clock in the operating system usually has drift, either systematic or random. This drift means the clock runs too fast or too slow. For this reason it is necessary to use some accurate time source to syncronize the operating system clock if accurate time is needed.
[my opinion:] Normally I'd just say: Use NTP. But your random time drift seems to be so high, NTP would freak out.
It seems to be a hardware problem, or some friend made a practical joke on you, inserting some random time drift in crontab. Try to reinstall your OS and check if this behavior continues. If so, you should change your motherboard. And try to get a good one, like Asus.
You don't say which timezone you are in, but I guess all 3 of you are in the same one. Perhaps you're the only 3 linux users in your zone, and the zoneinfo data is wrong!
(Zoneinfo can specify pretty much arbitrary time corrections - I used to have my own timezone with daylight savings just for an hour every day, so I could fool the timeclock software about what time I got back from lunch. Amazing what unix programs will believe, even when you're not root...)
The compiled zoneinfo files are binary, so a few corrupt bits could easily do this.
Try running 'TZ=GMT date' on a regular basis, and see if the underlying system time is jumping about, or only your 'local' time....
(As another poster said, the hwclock is only used at bootup time, to set the inital clock)
I don't care what anyone says, there *IS* a major problem with the Linux clock. I too have had the same problem with another distro. I wasted countless days trying to solve it, without success. My machine is dual booted with Windows (NO windows was not causing the problem!) and while the Linux boot had horrendously erratic time, Windows had no issues.
A month ago, I wiped the system and re-installed Linux. The problem went away but, now I have a different time problem. Now, my Linux clock runs slooowww when the systems is under any sort of a load. If the systems is left idle the clock keeps perfect time. Run Konqueror for a while and the clock goes to shit. Run an editor, doesn't seem to matter which, and the clock is worthless. Hell, let a screen saver run overnight and the clock loses 5 hours.
There is a problem with the clock!
Yeah, Win95 and Win98 lose time often. There's a great feature in the Novell network client that lets you fix the clocks that can help get around that problem. It automatically sets the clock to what the servers are set to, and as long as you keep them properly set, you don't have to worry about some old Win98 machine in the basement losing time and causing someone to miss a meeting.