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In this video, I want to tell you about BIOS and UEFI.

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So what is BIOS?

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BIOS is a basic input-output system.

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It's the legacy boot method, which was invented in 1981.

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It was introduced with the original PC standard.

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So in BIOS, hardware settings were written to CMOS and managed through BIOS.

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Typically by using a specific setup key on your computer.

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From the BIOS settings, the bootable disk is identified.

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And the bootloader itself was installed in a 512 bytes master boot record, the MBR.

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And that is on the primary disk of your system, which was identified as such in the BIOS.

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From there, the operating system was loaded and the bootable partition was indicated.

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On Linux, to load the operating system, GRUB2 is the default OS loader.

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Legacy bootloaders are Lilo and GRUB.

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And in the MBR, 64 bytes are available for saving the partition table.

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Nowadays, there is UEFI.

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UEFI was introduced in 2010, and it works with firmware on the motherboard that corresponds

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to parts of the operating system.

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And firmware setup can be used to manage hardware settings.

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And boot order and other boot-related items have moved to the operating system.

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That is why on UEFI systems, you will always find a directory with the name slash boot

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slash UEFI.

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That's an operating system standard.

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So this directory needs to exist on all operating systems to contain firmware settings that

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are required for booting.

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The operating system itself has to register with the UEFI firmware.

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And in the UEFI systems, a slash boot slash EFI partition with the file system type VFAT

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is used to contain all settings required to boot.

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UEFI normally works with GPT partition tables.

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And GPT partition tables are the standards that allow for addressing disks bigger than

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2 Tebibytes.

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In the next video, you'll learn a little bit more about working with UEFI from Linux.