Linux System Boot

Linux Boot Loader

/etc/default/grub

Linux kernel

list kenel modules: sudo lsmod

sudo apt search linu-generic-hwe

To hold a module making it not to upgrade

sudo apt-mark hold linux-generic-hwe-22.04

TO unhlod or enabling upgrade

sudo apt-mark unhold linux-generic-hwe-22.04

For dnf based distros

First install plugin

sudo dnf install 'dnf-command(versionlock)'

Lock kernel for upgrades

sudo dnf versionlock kernel

Communicate with hardware

System Calls: read, open, write, close