Boot Journey

Loader stage 🚀

Boot Loader (what it is and why it exists)

Firmware can’t load the whole OS by itself. So it hands control to a boot loader. The boot loader’s main job is to load the kernel and start it.

What a boot loader is

  • 🚀 A small program that starts your OS
  • Loads the kernel into memory
  • Passes important info (disk, boot options, etc.)

Why it is needed

  • Firmware is small and general-purpose
  • OS kernels are bigger and need setup
  • Sometimes you choose between multiple OS options

Control transfer flowchart (click boxes)

🧠 Firmware
Finds boot option
🚀 Boot Loader
Loads kernel
⚙️ Kernel
Starts core control
This is the main “handover chain” in booting.

Examples: Windows vs Linux

System Boot loader example What it typically does
Windows Windows Boot Manager Reads boot settings, loads Windows kernel parts
Linux GRUB Shows menu, loads Linux kernel + init system

Click to learn more (easy analogy)
Boot loader is like a “starter key”:
  • Firmware is the car’s electronics doing basic checks.
  • Boot loader is turning the key to start the engine.
  • Kernel is the engine running and controlling everything.