Win7+ubuntu Dual system Time inconsistency

Transferred from: http://blog.sina.com.cn/s/blog_55546df90100xkf3.html

Recently installed Ubuntu and Win7 dual system, but found that every time after entering the Win7 is always wrong, always 8 hours later than the local time, every time after the adjustment in Win7, but once again into the Win7 system, the time has changed back, So in the online search for reasons originally is the two system read time mechanism is different, now to specifically say the reasons and solutions:
Reason for the problem:

UTC is Universal time coordinated, reconciling the time

GMT is Greenwich Mean time, Greenwich Normal

The way Windows and mac/linux default on system hardware time is different:

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

Linux/unix/mac hardware time as UTC, the operating system display time is the hardware time through conversion, for example, Beijing time is gmt+8, the system display time is hardware time +8.

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

If your Ubuntu set time zone is Beijing time East Eight district, the current system time is 9:00am. The actual UTC time 1:00am is stored in the hardware. When you reboot into Windows, you will find that the time shown in Windows is 1:00am, which is eight hours slower than in Ubuntu. Similarly, after you change in Windows or synchronize the system time with the network, and then go to Ubuntu to see, the system will be 8 hours faster. In areas where daylight saving time is practiced, the situation may be more complicated.
Workaround:
The first of these changes is under Windows :
In the registry key: Hkey_local_machine\system\currentcontrolset\control\timezoneinformation\
Next, add a key with a data type of REG_DWORD, a name of Realtimeisuniversal, and a value of 1.
or copy the following program code to Notepad, then change the suffix of Notepad to cmd, then double-click on it.
————————————————————————
@echo off
Color 0a
Reg Add hklm\system\currentcontrolset\control\timezoneinformation/v realtimeisuniversal/t reg_dword/d 1
Echo.
ECHO has enabled Windows to identify the time that is stored in the motherboard CMOS for Greenwich Mean Time (GMT), which is the time that the system determines the current system based on the CMOS time and the time zone set.
Echo.
Pause

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The second method is modified under Ubuntu as follows :

Ubuntu turns on UTC by default, which is coordinated world time, while Win7 is using this timing method, which will result in a difference between windows and Ubuntu time calculations

You can use the following methods to get a consistent time:

sudo gedit/etc/default/rcs

Find this line: Utc=yes

Change Yes to No

Tags: Linux

Win7+ubuntu Dual system Time inconsistency