Linux Kernel Overview

What is the Linux Kernel?

The Linux kernel is the core software that acts as an interface between the hardware and various software applications running on your system.

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Checkuname

uname command can be used to view kernel versionand system information.

uname -rflag

Flag	Function
-r	View current kernel version
-i	View current hardware platform
-a	Print all information

After installing a new kernel version, a server reboot is required.

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Where is the Linux Kernel stored?

Typically, the kernel file itself (located within /boot) is prefaced with 'vmlinuz', for example:

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initrd

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What is initrd?

initrd (initialisation RAM disk) is essentially a set of instructions used to load the kernel. initrd is stored temporarily in system memory whilst the kernel is loaded.

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Which file in /boot is initrd?

The initrd file will be prefaced with just that - initrd:

initrd.img-5.15.0-106-generic

To check which initrd file is currently being treated as the primary one (which will be loaded on boot), you can check the symlinks (in /boot), as below:

initrd.img -> initrd.img-5.15.0-107-generic

initrd.img.old -> initrd.img-5.15.0-106-generic

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