Linux Kernel
The software between Application Space and Hardware space. Manages CPU, Memory, File Systems rescources.
Can be checked with a command uname -r
3 - kernel version
10 - magor release
el7 - oracle linux 7
uek (not in the screenshot) - unbreakable entterprise kerner
only el7 or el8 - standart red hat comapatible kernel
Documentation in Linux Kernel can be found on https://kernelnewbies.org/Documents
The kernel can be downloaded from https://www.kernel.org/
To check which kernels do we have on system
To change kernel