uefi BIOS和legacy BIOS 启动流程区别

当初查这两区别的时候还是17 18年，现在这两年几乎没有传统BIOS启动方式了。 计算机启动BIOS就两类：uefi BIOS和legacy BIOS， legacy BIOS就是我们平时嘴上常说的BIOS，uefi BIOS则是嘴上常说的的uefi。

为了区分，叫英文名称更好。

具体的区分信息来自维基百科。

来源地址：https://wiki.archlinux.org/index.php/Arch_boot_process#Firmware_types

 

Under BIOS

    1. System switched on - Power-on self-test or POST process
    2. After POST, BIOS initializes the necessary system hardware for booting (disk, keyboard controllers etc.)
    3. BIOS launches the first 440 bytes (Master Boot Record) of the first disk in the BIOS disk order
    4. The MBR boot code then takes control from BIOS and launches its next stage code (if any) (mostly boot loader code)
    5. The launched actual boot loader
    
Under UEFI

    1. System switched on. The Power On Self Test (POST) is executed.
    2. UEFI firmware is loaded. Firmware initializes the hardware required for booting.
    3. Firmware reads the boot entries in the firmware's boot manager to determine which UEFI application to be launched and from where (i.e. from which disk and partition).
    4. Firmware launches the UEFI application.
        4.1 This could be the Arch kernel itself (since EFISTUB is enabled by default).
        4.2 It could be some other application such as a shell or a graphical boot manager.
        4.3 Or the boot entry could simply be a disk. In this case the firmware looks for an EFI System Partition on that disk and tries to run the fallback UEFI application \EFI\BOOT\BOOTX64.EFI (BOOTIA32.EFI on 32-bit systems). This is how UEFI bootable thumb drives work.