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13

You are correct that frequencies that high would be completely unmanagable. Sending one bit per frequency would cause problems for various types of radio transmissions as well. So we have modulation techniques which allow more than one bit to be send. A touch of terminology: baud, most people will remember that term from the days of telephone modems, is the ...


12

Is it this problem? You need to look at /etc/default/rcS and change UTC=yes to UTC=no. This makes Ubuntu read and write to the hardware clock in the same way as Windows, using local time instead of UTC.


10

You can resolve the problem by running NTP. If it isn't already installed you should be able to do something like yum install ntp chkconfig --levels 235 ntpd on service ntpd start You may have to give it a while to sync the first time.


10

NTP is not an unnecessary component. It's the only sane way to keep a system clock updated against an atomic time source. You should install NTP, configure it to use your local pool time source, and everything will be fine.


7

Is the hardware clock set correctly? You could also have a dead BIOS battery, causing the hardware clock to reset to a default if the power is removed.


6

The solution is to use the adjtimex package to let your kernel know how much time really elapses during each kernel tick. If it's idea is different from reality, the system clock will run more quickly or more slowly. I quote from Making NTP Work on Hardware with Large Clock Drift: When installed, the package will normally run the adjtimexconfig ...


6

To the best of my knowledge, the timing in GPUs comes from the system; they don't have their own internal highly-stable clocks. There are products out there (affordable, last I checked) that'll pull high quality time from a couple of sources. Some pull it directly from GPS, though it does require the ability to Get an antenna where a GPS signal can be ...


5

A dedicated timing machine, even if low capability, can keep very, very accurate time. You just need to lock the NTP software in memory and give it the highest possible priority. It will take it a day or two to stabilize, in temperature, synchronization, and in measuring its own rate. But it's not difficult to get millisecond accuracy in a stratum 3. The ...


5

Newer versions of Xen do not have the clock sharing feature, and the independent_wallclock setting does not exits. Your best bet is to install ntpd on all guests as well as dom0. You can try openntpd for a simple ntp daemon.


5

Time can be a problem inside VMs but by the same token if done correctly can be as accurate as a physical machine. It may seem odd but I'm a huge fan of using my switches (always Cisco in my world) as my NTP sources - not only are they easy to setup as such but it they have the handy benefit of being your DG too usually - see if your switches can do this ...


5

If you were just using Linux I'd use mcollective for parallel execution of the ntpdate command. My ntpd doesn't have a -q option. I'm not familiar with similar tools for Windows. Just to be clear, you're more likely to get consistent time when running ntpd continuously since it also keeps clock drift at bay. Different computers have slightly different ...


5

Check to make sure both the server and client using the correct time zone, and that it's set to use/not use day light savings as would be correct for your location.


5

If you prefer to make the change to the windows installation: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation] Add a new dword named "RealTimeIsUniversal" and set it to 1


5

(This question might better fit on StackOverflow's sister site, ServerFault.com.) Yes, clock drift can be more drastic on hosted virtual machines when compared with physical hardware. (Normally you would set the VMware host server to sync with your NTP server of choice, then have the VMware Tools in each of the virtual machines sync with their parent host.) ...


4

You can stop the windows time service, this will prevent the computer from being able to sync with the domain controller. You can disable this service if you need it to not sync over a number of reboots. I would warn against doing this for a long period of time however, as if your local clock gets out of sync with the domain controllers time, you will have ...


4

A few seconds per day of time drift is not particularly unusual or unexpected on a physical machine in my experience, especially if the drift is fairly stable (i.e. not 1s one day, 10s then next, -2s the day after, ...). In VMs, the clock drifting by only 4s/day would be quite an achievement without clock management like NTP. Rather than jumping the time ...


4

From the hwclock man page on RHEL 4.6: This mode (we'll call it "11 minute mode") is off until something turns it on. The ntp daemon xntpd is one thing that turns it on. You can turn it off by running anything, including hwclock --hctosys, that sets the System Time the old fashioned way. To see if it is on or off, use the command adjtimex --print ...


3

VMware tools might do this for you, but Gentoo is not in the guest compatibility list so it may not work, or may take a lot of effort to get working. You could use ntp to keep the clock up to date, or schedule ntpdate to run. I am not sure if these are better methods than hwclock -s. One thing you may want to avoid is a method that simply changes the ...


3

What products fail due to w32tm being disabled? Time synchronization is critical for Kerberos authentication, but the use of the built in Windows Time service isn't required as far as I know. The use of third party products to manage the domain/network time isn't discouraged if time accuracy outside of the capabilities of the Windows Time service is needed. ...


3

The issue may be one of several clocks or timers are particularly inaccurate or possibly defective oscillator or timer / clock (including RTC) passive components (quartz crystal, and any related capacitors). If this is the cause you may not be able to entirely work around it, if accurate time is critical to you. The nVidia nForce2 chipset for motherboards ...


3

Are there any ntpd messages in /var/log/messages? As I was dealing with my EC2 NTP issues I noticed that NTP didn't like being too far out of sync and wanted a manual update. Perhaps you're too far out for it to decide it will update for you.


3

2 minutes a month isn't too bad. NTP should be able to happily correct that amount of drift. If it hasn't always been this way and you're able to take the machine down, then try replacing the CMOS battery. They're cheap and you might find that it resolves the issue. Anecdotal story for you: I have in the past seen a running machine which was exhibiting ...


3

Yep, in Linux you can use hwclock --systohc, and pay your attention to its manual saying that «… The time shown is always in local time, even if you keep your Hardware Clock in Coordinated Universal Time. See the --utc option. Showing the Hardware Clock time is the default when no function is specified. …» And, BTW, my man hwclock also reveals ...


3

Kerberos is time-critical and won't work if the server and the client are too much out of sync.


3

Turn ntpd back on. It's job is to figure out how fast the clock is running and apply an appropriate correction.


3

Virtual servers have notoriously unreliable clocks, since they don't get reliable ticks from the CPU. They're even worse than the clocks in physical machines. It depends mostly on the load of the hypervisor your VPS is running on, so maybe you're seeing more drift since the load of the physical server has increased. Simply enable NTPD, and point it to some ...


3

Can you provide the specific version of CentOS 5 as well as the server manufacturer and model. That may help... But one thing you can try on CentOS 5 is appending clock=pmtmr to the end of your kernel boot line in the Grub menu or in /etc/grub.conf and restarting the system. Explanation here.


3

If you are willing to spend more time getting this to work you can always use virtualization and get guest system clock to run faster. Here http://sysnet.ucsd.edu/projects/time-dilation/ you can find patches for xen that allow you to slow the guest system down (the opposite of what you want to achieve), so some modifications might be required.


3

Write a shell script that sets the system time and then waits for the results of the next job, then sets the system time again and waits for the results of the next job... Repeat until done.


3

I would either verify that the server time is synchronized with XEN host echo 0 > /proc/sys/xen/independent_wallclock or I would disable this method and configure standalone time synchronisation via NTP echo 1 > /proc/sys/xen/independent_wallclock yum install ntp service ntpd start chkconfig ntpd on Put this line to /etc/sysctl.conf to make ...



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