mahfuzhasanreza / linux-boot-system-documentation

A documentation of Linux Boot Process (Startup Sequence).

linux-boot-system-documentation

Linux Boot Process Sequence

1. Click Power Button to start
2. CPU works
3. BIOS/UEFI
   • Perform POST (Power On Self Test)
   • Check for bootable device
4. MBR
   • Load the boot loader (446 byte) into the memory
5. GRUB
   • Load boot/grab/grab.cfg
   • GUI asking OS
   • Select Kernel
   • Load to RAM
6. Kernel
   • Load the driver from temp.system
   • Initialized the first process init/systemD
7. SystemD
   • Start all require process
   • To bring system to run_level/targets

Info

• CPU: Central Processing Unit
• BIOS: Basic I/O (Input-Output) System
• UEFI: Unified Extensible Firmware Interface
• MBR: Master Boot Record
• GRUB: GRand Unified Bootloader
• GUI: Graphical User Interface
• SystemD: System Daemons

Author: Mahfuz Hasan Reza

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