PlanetEnjoy.com

Atomic Clock Sync

While WorldTimeServer.com can help you look up accurate times around the world, we see lots of interest from our users in keeping your local computer clock accurate, too. Atomic Clock Synchronization is the best way to make this happen.

Atomic clock servers are operated by many governments and some large organizations. These atomic clock servers can be contacted to synchronize a local time with the server’s time. This is vital for applications like GPS or Airport Traffic Control, but is useful for our own computers as well. There are two things you need, however, to keep your pc time updated with current times from an atomic clock service…
You need current and correct time zone rules on your computer!

IMPORTANT NOTE: You must have the correct time zone selected on your computer AND have the correct daylight saving time rules in place in your operating system in order to have an Atomic Clock Sync work properly. If you live in the US or Canada, the dates for DST changed in 2007 so you must update your operating system with the new rules or synchronizing might set your clock based on the old rules. (Microsoft releases patches when necessary for newer versions of Windows, but with older versions, you may have to update the registry yourself or find a third-party tool to do it.)
You need software to sync with an atomic clock server

If you use Windows Vista, XP, or 2000, there is atomic clock synchronization software built-in, so downloading other synchronization software is not required!

There are many programs to perform an atomic clock sync available for older operating systems which do not have synchronation built in. These programs can also be easier to configure or have more features than the built-in free tools your computer came with.

Using Windows XP Built-in Atomic Clock Sync

To use Windows XP’s built-in options as an example, to check your synchronization settings, look for the clock at the bottom right and double click on the time to bring up your time settings. You can adjust your local time and date by hand on the first tab, you can adjust your time zone location on the second, and on the third, labeled Internet Time, you can view your current atomic clock sync settings.

A few things to notice about this screen:

1. atomic clock sync settings screenshotThe checkbox must be checked for XP to compare your local pc clock with an atomic clock server on a scheduled basis.
2. The server list lets you pick from a short list of time servers (usually only neccessary when the current server you are using is giving you an error).
3. You will see the results of the last time check, which in this screen shot, shows a successful sync as well as the time it took place.
4. Near the bottom is a “Next synchronication:” value which will let you know how long it will be until XP checks your local time accuracy again.

Some common questions from advanced users might be “Can I add more time servers?” and “Can I synchronize more often?” The answer to both is a qualified yes … if you have administrative rights on your PC and are comfortable editing the registry.

Disclaimer: Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from modifications to the registry can be solved. Use the information provided at your own risk.

To synchronize more often, find the W32Time registry key given below modify the existing value called “SpecialPollInterval”. If you don’t see SpecialPollInterval listed in this section, you can create it as a new DWORD value. The value of this should be set to the number of Seconds between sync attempts. If you wanted to check once per day, the value would be 86400.

System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient]
Value Name: SpecialPollInterval
Data Type: REG_DWORD (DWORD Value)
Value Data: Seconds in Decimal

To add more time servers, first check to see if your version of Windows will let you simply type them in on the screen shown above. If so, this saves you the trouble and possible problems of editing the registry yourself. If you need to add them manually yourself, find the registry key for DateTime Servers provided in full below and create a new string value. Name it the next number in sequence (usually ‘3′) and set the data of the new value to equal the hostname or IP address of the time server.

You can also change the default server by setting the value of “(Default)” to the entry number of the required server.

System Key: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\DateTime\Servers]
Value Name: (Default)
Data Type: REG_SZ (String Value)
Value Data: Server Hostname or IP Address