Solved Dual Boot Messing Up My Clock ???

[BuckSkin]

It took me a bit to figure out the culprit in this situation, but I now have the suspect list narrowed down to one.

I recently installed Linux ZorinOS in dual-boot configuration on one of our machines; both Windows 7 Pro and ZorinOS reside on the same HDD.

I got to noticing that the clock in Windows was mysteriously and very randomly jumping ahead six hours; six hours just happens to be my offset from Greenwich Mean Time, Greenwich being six hours ahead of me.

I finally realized that this was happening after I would boot to Linux and then boot back into Windows.

Curiously, it does not affect the time in ZorinOS; it is always correct.

As much research as I did before I jumped into the Linux boat, I never read of this happening; am I the only one to ever experience this ?

Is there a cure ?

Thanks for reading and Happy Holidays, Merry Christmas, and Happy New Year !

 

[FreeBooter]

There is no way Linux or any other dual booted operating systems can alter each other clock that is been displayed this is a weird issue have a go at suggestions at below website link.

How to Fix an Incorrect Windows Clock

 

[BuckSkin]

There is no way Linux or any other dual booted operating systems can alter each other clock that is been displayed this is a weird issue have a go at suggestions at below website link.

How to Fix an Incorrect Windows Clock

I figured my clock problem was going to be a rare situation when I could find no reference to anyone else experiencing it.

Thanks for the link.

 

[FreeBooter]

I thought issue could be cause by CMOS battery but you said Linux OS not affected with wrong clock been displayed but just in case you should check to see if BIOS have the correct clock.

 

[ethel]

Hi Buckskin, This previous post may help you to read, as it was someone having the same issue with the

clock using Linux and Windows.

Time is always wrong (

1 2)

 

[MSClin]

That's because Linux uses UTC time and Windows uses local. The solution is to make Windows use UTC time or make Linux use local time. Making Linux use local time has downsides as well as Windows with UTC. The less destructive solution is to make Windows use UTC time, in my opinion. Below you can find numerous ways to change the time that Windows or Linux use.

Windows:

Note: The below command sc config w32time start= disabled disables "Windows Time" service, a service that synchronizes Windows' time with an internet server. This means that if you manually change your time or if Windows' time is already incorrect, it will never correct/sync itself. This change is made because Windows' time service is not fully compatible with UTC, therefore it is recommended to be disabled, although if you have problems with time in Windows after doing the steps below, you can leave it enabled and skip the last step in the following solution.

1:
> Windows key + R and type cmd then click OK OR search cmd then right-click on it and choose Run as administrator
> Type/copy reg add "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation" /f /v RealTimeIsUniversal /t REG_DWORD /d 1
> Type/copy sc config w32time start= disabled

Linux:

1: For newer distros:
# timedatectl set-local-rtc 1

2: Sed one-liner for old distros:
# sudo sed -i 's/UTC=yes/UTC=no/' /etc/default/rcS

More on this topic, how and why it happens, etc. you can read here - System time - ArchWikihttps://wiki.archlinux.org/index.php/time

 

[Megahertz07]

That's because Linux use UTC time and Windows use "Local". The solution would be to make Windows use UTC time or to make Linux use Local time. I prefer to make Linux use Local, because it's just easier.

 

[FreeBooter]

I think some of us should learn how dual booting works. Computer with multiple operating systems per storage device is a dual-booting computer that stores both Windows and Linux on the same disk drive. In this case a multi-booting boot loader is necessary. Also, the disk must be partitioned to give each operating system its own partition on the disk drive.

Linux does not know how to modify Windows settings no operating systems can modify offline operating systems settings also configurations of one operating system does not applied to any other operating systems which is installed on its own partition.

Linux time configuration cannot affect time configuration of Windows OS if anyone claims it can does not know how operating system works and does not understand how dual booting works.

 

[Megahertz07]

Windows uses local time and update the hardware clock (a.k.a. the Real Time Clock (RTC) or CMOS clock).
Linux uses GMT or UTC time and also update the hardware clock (a.k.a. the Real Time Clock (RTC) or CMOS clock).
Time - ArchWiki

So when you run Linux it will set the hardware clock (RTC) to UTC time and make a correction due to the time zone to show the local time clock.
When you run windows it will load the hardware clock (RTC) that has been set to UTC by Linux. It will show GMT or UTC time until Windows makes the change to local time.

I have just made the MSClin suggestion (post #6) adding utc=no in /etc/default/rcS and it made the magic.

 

[FreeBooter]

A real-time clock (RTC) is a computer clock (most often in the form of an integrated circuit) that keeps track of the current time. Two clocks are important in Linux: a ‘hardware clock’, also known as RTC, CMOS or BIOS clock. This is the battery backed clock that keeps time even when the system is shut down. The second clock is called the ‘system clock’ or 'kernel clock' and is maintained by the operating system. At boot time, the hardware clock is read and used to set the system clock. From that point onward the system clock is used to track time.

Windows OS does not modify RTC and in Linux OS you will need to use tool called hwclock for accessing one of the hardware clocks directly. You can display the current time, set a hardware clock to a specified time, set a hardware clock to the system time, and set the system time from the hardware clock.

As you can see Linux also does not modify RTC by default only way to do it is to use a tool called hwclock.

 

[Megahertz07]

Windows does synchronize with a server and modify the RTC to local time.
Linux does the same but modify the RTC to UTC - GMT

 

[FreeBooter]

I think we both sticking with our own knowledge of how RTC works so there is no point for us to explain how operating systems works with RTC.

 

[MSClin]

Everything Megahertz07 said is true... At least read the link which Megahertz07 pointed to. I will even quote the answer from there:

If you have multiple operating systems installed in the same machine, they will all derive the current time from the same hardware clock: for this reason you must make sure that all of them see the hardware clock as providing time in the same chosen standard, or some of them will perform the time zone adjustement for the system clock, while others will not. For example, if the hardware clock was set to localtime, more than one operating system may adjust it after a DST change, thus resulting in an overcorrection; more problems may arise when travelling between different time zones and using one of the operating systems to reset the system/hardware clock.

This is the simple explanation to the problem the OP have.

 

[lehnerus2000]

Linux time configuration cannot affect time configuration of Windows OS if anyone claims it can does not know how operating system works and does not understand how dual booting works.

You have no idea what you're talking about.
As a rule, a Linux OS won't directly write changes to a Windows OS without user intervention.

The "Linux Time vs Windows Time" issue has been well documented for many years.
I have personally experienced it for at least 8 years (especially when using Live Linux CD/DVD/USB).

I've recently had to perform the hacks that MSClin posted on my installed operating systems.

 

[FreeBooter]

You have no idea what you're talking about.

The "Linux Time vs Windows Time" issue has been well documented for many years.
I have personally experienced it for at least 8 years (especially when using Live Linux CD/DVD/USB).

I've recently had to perform the hacks that MSClin posted on my installed operating systems.

Wow so you are saying Linux can configure offline settings of Windows OS i think you have no idea what we are talking about because we have now established Linux time settings could configures RTC not the Windows OS time settings.

 

[BuckSkin]

Hi Buckskin, This previous post may help you to read

That's because Linux use UTC time and Windows use "Local". The solution would be to make Windows use UTC time or to make Linux use Local time. I prefer to make Linux use Local, because it's just easier.

So when you run Linux it will set the hardware clock (RTC) to UTC time and make a correction due to the time zone to show the local time clock.
When you run windows it will load the hardware clock (RTC) that has been set to UTC by Linux. It will show GMT or UTC time until Windows makes the change to local time.

I have just made the MSClin suggestion (post #6) adding utc=no in /etc/default/rcS and it made the magic.

Thanks, everyone; I will make a stab at this.

I have never yet messed with the Linux version of Command Line; I am assuming that is where I enter this text, or am I misunderstanding ?

Thanks and have a Happy New Year !

 

[MSClin]

I have never yet messed with the Linux version of Command Line; I am assuming that is where I enter this text, or am I misunderstanding ?
!

You talk about "UTC=no"? If so, I'll just give you a simple command to make Linux use Local time. Open Terminal (that's how command line is called in Linux) and enter this command:

timedatectl set-local-rtc 1

Wow so you are saying Linux can configure offline settings of Windows OS i think you have no idea what we are talking about because we have now established Linux time settings could configures RTC not the Windows OS time settings.

I even quoted the cause of this problem, yet you still refuse to understand. "If you have multiple operating systems installed in the same machine, they will all derive the current time from the same hardware clock". And by this you should understand that if the hardware clock was set for example to UTC time, if Windows try to read it (as Windows uses Local time standard), the time would be displayed wrong in Windows. That's why every OS should use the same standard to read the hardware clock.

And the things you say doesn't make any sense. Nobody said that "Linux can configure offline settings of Windows", we basically said that if hardware clock is read with different standards, the time would be displayed wrong. All we said in this thread is documented here > Time - ArchWiki.

 

[FreeBooter]

That's because Linux use UTC time and Windows use "Local". The solution would be to make Windows use UTC time or to make Linux use Local time. I prefer to make Linux use Local, because it's just easier.

Linux:
1. Edit "UTC=yes" to "UTC=no" in /etc/default/rcS.

Windows:
But if for some reason you want Windows to use UTC... Open Notepad and paste this code:

Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation]
"RealTimeIsUniversal"=dword:00000001

Then save the file as "WindowsTimeToUTC.reg" and double-click to merge it with the registry. But this is not everything, you should open CMD and disable Windows Time service with this command:

sc config w32time start= disabled

Now you're finished with Windows.

Hi MSClin,

As you can see you have not mentioned about Linux modifying RTC chip setting.https://www.sevenforums.com/members/megahertz07.html

 

[MSClin]

Hi MSClin,

As you can see you have not mentioned about Linux modifying RTC chip setting.

Do I have to? I like to provide fast help to the people who have problems, not give them information which they can get by using Google.

 

[FreeBooter]

Well you should so those helping and OP can learn from you.