As any operating system, Linux operating systems also has to go through some steps to represent the desktop environment to the end user. Here are the step by step process before linux shows the desktop session.
Linux Boot Process
- Step 1 ( Power On Self Test ) : When the computer is turned on, the hardware does a self test to check if all the components like CPU, Memory , Hard Drive are working properly.
- Step 2 ( BIOS or UEFI Intialization ) : After powering the maching, the first thing it runs is BIOS ( Basic Input/Output System ) or UEFI ( Unified Extensible Firmware Interface ). BIOS and UEFI are firmware interfaces that computers use to boot up the Operating System. The difference between BIOS and UEFI is that BIOS uses the Master Boot Recorder ( MBR ) and UEFI uses the GUID Partition Table ( GPT ).
- Step 3 ( Bootloader ) : After BIOS or UEFI has run the configuration , it will select a boot storage device like Hard Drives, USB Drives, CD Drives based on their order and run the bootloader. The bootloader is typically installed in MBR or EFI System Partition. The most commonly used Bootloader for Linux is GRUB ( GRand Unified Bootloader ) which is responsible for loading the linux kernal into the memory.
- Step 4 ( Kernel Initialization ) : The kernel is the core of the Operating System and it manages the system resources, sets up data structures, initialize drivers and performs important tasks to prepare the linux system. This happens when the bootloader loads the kernel into the memory.
- Step 6 ( Init System ) : After the kernel has been initialized, it runs the operating system startup process, system files like systemd, Upstart
- Step 7 ( Service Initialization ) : After the Init System, it runs daemon , system services like network manager, device manager etc.
- Step 8 ( User Space Initialization ) : At this point the linux operation system is close to show The terminal and the display manager. Here you will the terminal login prompt and then the display manager pops up if the linux os has any
- Step 9 ( User login ) : Now the user can login into his account using username and password authentication and then sees the window manager with wallpaper manager and panel if it has any
- Step 10 ( System Operation ) : Now the user can execute commands and perform various linux tasks based on their privilege and access rights.
That’s how the Linux finishes booting to represent linux services.
You can check the below video to see how the steps works on a real Linux Operating System.
Link :
Byronic 