Re: General Question About BIOS and UEFI

Le 27/07/2021 à 16:40, tb a écrit :
> Newbie question...
> 
> If I were to purchase some kind of mainstream desktop PC without any OS
> preinstalled and if I were to boot up such PC and press F2 repeatedly,
> would I find myself in the BIOS screen or the UEFI screen?
> 
> Or maybe the UEFI screen is available only if Microsoft Windows is
> installed?
> 


UEFI *is* the BIOS, in a way. The UEFI software is the bit of code that 
your computer runs when you power it on, the same way the BIOS did on 
older computers. Some UEFI implementations support the CSM which allow 
older software relying on legacy BIOS interrupts to work properly.

A 2021 mainstream desktop PC doesn't have any BIOS code similar to what 
you'd find on an older computer, and pressing F2 would open the UEFI 
firmware setup screen.

Windows kind of blurred the line between firmware and operating system 
for the average user since most computers sold since 2012 that ship with 
Windows >= 8 don't allow entering the firmware by pressing a key at 
startup, forcing you to boot into Windows, to enter an "Advanced 
Startup" menu, and to click "UEFI Firmware settings" from there, which 
is really dumb given that a lot of times you want to enter the firmware 
because your OS crashed and you need to reinstall it and boot from 
another device.