In this video, I want to tell you about BIOS and UEFI.
So what is BIOS?
BIOS is a basic input-output system.
It's the legacy boot method, which was invented in 1981.
It was introduced with the original PC standard.
So in BIOS, hardware settings were written to CMOS and managed through BIOS.
Typically by using a specific setup key on your computer.
From the BIOS settings, the bootable disk is identified.
And the bootloader itself was installed in a 512 bytes master boot record, the MBR.
And that is on the primary disk of your system, which was identified as such in the BIOS.
From there, the operating system was loaded and the bootable partition was indicated.
On Linux, to load the operating system, GRUB2 is the default OS loader.
Legacy bootloaders are Lilo and GRUB.
And in the MBR, 64 bytes are available for saving the partition table.
Nowadays, there is UEFI.
UEFI was introduced in 2010, and it works with firmware on the motherboard that corresponds
to parts of the operating system.
And firmware setup can be used to manage hardware settings.
And boot order and other boot-related items have moved to the operating system.
That is why on UEFI systems, you will always find a directory with the name slash boot
slash UEFI.
That's an operating system standard.
So this directory needs to exist on all operating systems to contain firmware settings that
are required for booting.
The operating system itself has to register with the UEFI firmware.
And in the UEFI systems, a slash boot slash EFI partition with the file system type VFAT
is used to contain all settings required to boot.
UEFI normally works with GPT partition tables.
And GPT partition tables are the standards that allow for addressing disks bigger than
2 Tebibytes.
In the next video, you'll learn a little bit more about working with UEFI from Linux.