- Click the power button on
- CPU load instruction from firmware chip on the motherboard and execute it
- Firmware code does initialize and tests system hardware.
- Firmware start bootloader and give the next step to the boot loader.
Two famous firmware:
- BIOS firmware
- UEFI firmware
- Frequently is stored in ROM
- Initializes and tests system hardware
- Bases on user predefined prioritized boot device, BIOS try to check each device in order to see if it is bootable by trying to load MBR.
- From valid MBR, BIOS loads boot loader and give next step to it.
- Special type of boot sector
- The very beginning of the partitioned hard disk
- Designed to replace BIOS firmware
- Initializes and tests system hardware.
- UEFI, or user let UEFI knows which boot loader is used. Not dependent on disk and MBR.
- Boot loader of UEFI is stored in the EFI system partition of the hard drive GPT partition type.