Why does linux not take effect immediately?

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lxmint123
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Why does linux not take effect immediately?

Post by lxmint123 »

Hi there,

Well I installed linux mint and I started to play around. I updated my kernel to the last version, but when I then typed 'uname -r' I still saw the old version being installed so I though "uh, how's that possible" so I restarted the computer and wrote it again 'uname -r' and I finally saw that it has been changed. Anyway why did I have to restart the machine to see it take effect? But that was not the only problem, when I restarted I had a problem with my wifi it didn't work anymore so i went on google looking for a solution and found some, I tried them but none of them worked I got some errors, anyway I restarted the computer went back to google and retried the solutions again and that time it worked? Why is linux so buggy?

I don't know, maybe it's me.

Anyways thanks for answers :)
Cosmo.
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Re: Why does linux not take effect immediately?

Post by Cosmo. »

lxmint123 wrote:Why is linux so buggy?
Is this really the case? Tell me an OS, where you can switch the kernel on the fly. Or an program, that does not need to get restarted after an update.
The kernel gets loaded during bootup, it is - as the name says - the core of the OS. Theoretical: If you would remove / replace it during the system is running the whole system would crash.
How do you name Windows, where nearly every MS-patch makes a reboot necessary?

Another question is, why is your hardware not compatible with newer kernel versions? It is a known fact, that this is the case - you may blame the kernel or the hardware - some hardware discontinues to work.

Third question: Why did you change the kernel? Did you encounter any problem with the older one?

Fourth question: Which old and which new kernel? Which version of Linux, which desktop environment?
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ajcardiac
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Re: Why does linux not take effect immediately?

Post by ajcardiac »

It's nothing to do with Linux being buggy.

You took the decision to update the Kernel - why?
Really, how do you expect a Kernel change to be implemented during an active session?

Why are you surprised that a piece of hardware now no longer works?

Why not select the previous Kernel at boot and see if that solves the issue?
If so, remove the newer Kernel.
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lxmint123
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Re: Why does linux not take effect immediately?

Post by lxmint123 »

Is this really the case? Tell me an OS, where you can switch the kernel on the fly. Or an program, that does not need to get restarted after an update.
The kernel gets loaded during bootup, it is - as the name says - the core of the OS. Theoretical: If you would remove / replace it during the system is running the whole system would crash.
How do you name Windows, where nearly every MS-patch makes a reboot necessary?

Another question is, why is your hardware not compatible with newer kernel versions? It is a known fact, that this is the case - you may blame the kernel or the hardware - some hardware discontinues to work.

Third question: Why did you change the kernel? Did you encounter any problem with the older one?

Fourth question: Which old and which new kernel? Which version of Linux, which desktop environment?
1: I agree, but atleast windows tells you that you need to reboot the system to take effect. But logically thinking you are right every update you make would need a reboot.

2: I don't know, the new kernel I installed works just fine now.

3: Well I thought it would be good to keep it up to date lol is this even necessary? I really would like an answer from you, i'm a real noob bro :p

4: I think it was 3.16 and now 1.19. No I had no problem with the old one, but as I said I thought it was necessary to keep it updated.
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MartyMint
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Re: Why does linux not take effect immediately?

Post by MartyMint »

ajcardiac wrote: You took the decision to update the Kernel - why?
Old Windows habits (latest must be the greatest) die hard.
Cosmo.
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Re: Why does linux not take effect immediately?

Post by Cosmo. »

lxmint123 wrote:But logically thinking you are right every update you make would need a reboot.
In Linux not really. For a kernel: yes (with the possibility to choose between the installed versions). For a driver: sometimes. For other things: very seldom. Even services could be stopped an newly started inside the running system, although simply logging out and back in is for many users more comfortable and does the same job.
lxmint123 wrote:3: Well I thought it would be good to keep it up to date lol is this even necessary? I really would like an answer from you
...
4: No I had no problem with the old one, but as I said I thought it was necessary to keep it updated.
Also the kernel 3.16 (as example) is up-do-date. If you have no problem with your hardware, this not only not necessary, but in a number of cases a regression.

General rule: Update for a reason (I hope Clem does not mind that I use his advice).

And before you update a kernel, inform yourself beforehand, how you can choose the loaded kernel before booting. Here you go:
If you should not see the grub menu before the real boot process (this is typically the case with single-boot machines) hold and press the shift-key immediately after powering on, until you see it. You will see (normally) in the first row the newest installed kernel, which will boot automatically after some seconds. In the next line you can open a sub-menu for the older kernels, where you can select and load them.
lxmint123
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Re: Why does linux not take effect immediately?

Post by lxmint123 »

Cosmo. wrote:
lxmint123 wrote:But logically thinking you are right every update you make would need a reboot.
In Linux not really. For a kernel: yes (with the possibility to choose between the installed versions). For a driver: sometimes. For other things: very seldom. Even services could be stopped an newly started inside the running system, although simply logging out and back in is for many users more comfortable and does the same job.
lxmint123 wrote:3: Well I thought it would be good to keep it up to date lol is this even necessary? I really would like an answer from you
...
4: No I had no problem with the old one, but as I said I thought it was necessary to keep it updated.
Also the kernel 3.16 (as example) is up-do-date. If you have no problem with your hardware, this not only not necessary, but in a number of cases a regression.

General rule: Update for a reason (I hope Clem does not mind that I use his advice).

And before you update a kernel, inform yourself beforehand, how you can choose the loaded kernel before booting. Here you go:
If you should not see the grub menu before the real boot process (this is typically the case with single-boot machines) hold and press the shift-key immediately after powering on, until you see it. You will see (normally) in the first row the newest installed kernel, which will boot automatically after some seconds. In the next line you can open a sub-menu for the older kernels, where you can select and load them.
Thanks a lot for the info, I didn't know it was still possible to load the old kernel, I still got a lot to learn :mrgreen:.
Cosmo.
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Re: Why does linux not take effect immediately?

Post by Cosmo. »

I give you another thing to learn:
Please do not make a full quote of a post, it does not make sense at all and forces everyone to scroll down for getting to the text, he did not already have read a second ago. In many cases no quotes are necessary at all (you may use the "Reply" button at the bottom left), otherwise you should only quote exactly, what you need to have as a reference, so that the readers know, what you are referring to.
Imagine I would have done full quotes also, and then you quote me, I again you and so on. Your last post would have been endlessly, before the scrolling non-reader finds your single line. And now imagine, some people use a small screen and a low resolution - or read with a tablet or a smartphone.

Full quote is especially disturbing, if the quoted post is placed immediately above the quote.

Thank you for understanding.
Mute Ant
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Re: Why does linux not take effect immediately?

Post by Mute Ant »

''Why does Linux not take effect immediately'' Your CPU can only execute code copied from storage into RAM. When it's a Firefox upgrade, you shut it down and restart to get the new version loaded. Same with a kernel, but everything loaded by the kernel has to shut down first. That's a design decision from long ago, unchanged, because it works. There's no technical reason why control can't be switched to a new kernel at that point. The TAILS distro does exactly that, to clear out the RAM for a secure shutdown.

In Debian, the mean bugginess is around 2 per package...https://www.debian.org/Bugs/
While you're waiting, read the free novel we sent you. It's a Spanish story about a guy named "manual".
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MtnDewManiac
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Re: Why does linux not take effect immediately?

Post by MtnDewManiac »

lxmint123 wrote:1: I agree, but atleast windows tells you that you need to reboot the system to take effect.
...and it seems to do so an awful lot. The users of Microsoft OS appear to be comfortable with this reboot requirement, even expect it. IDK, perhaps this is a leftover from when Microsoft Windows tended to crash a lot (I am assuming that it is at least somewhat less prone to this behavior these days :lol: ) and treat its users to the infamous Blue Screen of Death, lol?

The users of linux OS, OtOH, expect their systems to be much more stable for the most part, can get quite put out if their system crashes, and have been known to go weeks or even months (years, lol?) without a reboot. So they're much more likely to reboot when they want to, as opposed to the OS requiring them to (regularly).
lxmint123 wrote:3: Well I thought it would be good to keep it up to date lol is this even necessary? I really would like an answer from you, i'm a real noob bro :p

4: I think it was 3.16 and now 1.19. No I had no problem with the old one, but as I said I thought it was necessary to keep it updated.
New kernels are released to add features that new(er) hardware can take advantage of, to fix certain issues, or both. If you do not have that newer hardware and aren't experiencing those issues... No, there would be no reason to update to a newer kernel.

There are lots of kernels. If you run your Update Manager and go to View / Linux kernels, you can view a list of some of them. In addition to noting whether or not each one is installed and/or loaded, you'll also see whether or not it is recommended (my guess is that most will not be) and be able to read about specific fixes - and regressions that are introduced. And, as always, the lists will only mention ones that are known.

Do not blindly update your kernel.
Cosmo wrote:Please do not make a full quote of a post
Especially if the person that is being quoted is known for (occasionally :wink: ) typing in posts of 15,000 to 30,000 characters, lol. (Err... I guess that might be me.)

Regards,
MDM
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