Linux and win7 dual-system time error

A while ago, we installed centos 5.4 and win7 dual systems. It was found that the system time in win7 was incorrect, and the machine was not connected to the Internet. During the boot every day, it would be slow for 8 hours. I don't know what's going on, because I was busy with other things, so I had to find the reason after a few days, later I found that the Windows Time Service was not automatic, so I think this is the reason.

No exception was found after several times of use, because no network cable was inserted when the system was started up today and it went directly into ubuntu. It took nearly 8 hours to plug in the network cable, so I thought it was not normal, so I restarted Windows 7 and found that it was 8 hours slow, so I realized that the two systems may have different settings, resulting in this time problem. So Google:

Two concepts:

Universal Time Coordinated

GMT is Greenwich Mean Time, Greenwich Mean Time

By default, Windows and Mac/Linux are different in terms of system hardware time:

Windows treats the system hardware time as local time, that is, the time displayed in the operating system is the same as the time displayed in the BIOS.

Linux/Unix/MAC uses the hardware time as UTC, and the time displayed in the operating system is converted by the hardware time. For example, Beijing time is GMT + 8, the time displayed in the system is hardware time + 8.

In this way, a problem occurs when multiple systems coexist in the PC.

Assume that the time zone set in Linux is UTC + 8 (Beijing Time). The current system time is AM. In this case, the hardware actually stores the UTC time am. After you restart Windows, you will find that the time displayed in Windows is am, eight hours slower than in Linux. Similarly, after you change the system time in Windows or use the network to synchronize the system time, and then go to Linux to see it, the system will be 8 hours faster. The situation may be more complex in the region where renewal is implemented.

Solution:

1. Ensure that Ubuntu does not use UTC time consistent with windows. By default, UTC is enabled for Ubuntu, that is, Coordinated Universal Time, while win7 uses this timing method. This results in a difference in time computing between windows and ubuntu.

You can use the following method to get the same time:

Sudo gedit/etc/default/RCS

Find this line: UTC = Yes

Change yes to No.

In fedora (I am fedora 13), Open System-> Administration-> Date & time at a time. On the time zone tab, remove the check box before system clock uses UTC and click OK. The system will be normal in a few minutes.

2. Modify the way Windows treats hardware time, so that you do not need to set it on Ubuntu only after modification on Windows.

Let windows treat hardware time as UTC

Start-> Run-> cmd, open the command line program (Vista needs to open the command line program as an administrator to have permission to access the Registry), enter the following command in the command line, and press ENTER

Code:

Reg add HKLM \ System \ CurrentControlSet \ Control \ timezoneinformation/V realtimeisuniversal/T REG_DWORD
/D 1

Original article: http://mtoou.info/linux-win7-shijian/