What does it mean to install a kernel

kernel

What does it mean to install a new version of the kernel. My Linux box gave me this message when I was updating,

NOTE, 3.8.13 was the last maintained maintenance release by Greg Kroah-Hartman.
It is recommend to move on to linux310-series.

What I want to know is,

  • Is it really that simple to only change the Linux kernel?
  • Is the Linux kernel like a simple executable file that can be swapped out for another Linux kernel?
  • What happens if I install a new kernel while the box is already running another version of the kernel?
  • Right now I'm using Kernel 3.8.13.8-1. Is it really okay to move to the linux310-series as the above update message says?

Best Answer

  • Yes.
  • Yes, sort of. It's not simple and it's not "just" an executable file, but you can swap between Linux kernels super easily. This is not applicable to every kernel, though, meaning that e.g. you can probably replace a FreeBSD kernel with a newer FreeBSD kernel, and as stated above, you can upgrade a Linux kernel pretty easily, but you cannot easily replace a Linux kernel with a FreeBSD kernel. See the Wikipedia page on kernels. I'd link you to the "what is a kernel" question, but I can't find it.
  • Your box will continue to use your current kernel. It depends on your bootloader and distribution, but when you reboot, you'll probably be able to choose between the two kernels.
  • Probably. Upgrading your kernel isn't actually a big deal, especially since (if you're smart, and keep your old kernel around just in case) you can go back to the old one if the new kernel doesn't work for some reason. Sometimes there are problems with new kernel versions, especially if you have exotic hardware, but I've never seen any myself.
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