Tutorials: Under the Hood: How the Linux Kernel and systemd Boot Your System
Tutorials: Under the Hood: How the Linux Kernel and systemd Boot Your System The Linux boot process follows a strict, step-by-step sequence to transition your system from a powered-off state into a fully usable operating system. Here is a breakdown of the 6 core stages of the Linux boot sequence: 1. BIOS / UEFI (Hardware Initialization) When you press the power button, the system motherboard runs its firmware—either the traditional BIOS (Basic Input/Output System) or the modern UEFI (Unified Extensible Firmware Interface). POST (Power-On Self-Test): The firmware initializes and checks your hardware components (RAM, CPU, storage drives, graphics card). MBS/EFI Detection: Once the hardware passes the test, BIOS searches for a Boot Sector (Master Boot Record - MBR) on the primary drive. UEFI skips the MBR search and reads its configurations directly from a dedicated system partition called the ESP (EFI System Partition) to find a bootloader file ( .efi ). 2. Bootloader (GRUB2) The f...