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That.. ^ And research I have done indicates that the linked article in the questoner's post is really wrong. UEFI does replace the BIOS. A computer runs either a UEFI, or if it's very old, then a BIOS. Sometimes colloquially the term BIOS is used for the configuration screen, but it's part of the UEFI and techies will often jump in and correct and say UEFI not BIOS. Some may use the term BIOS for anything run by the CPU before the boot loader, even if it is a UEFI, but it's a colloquialism and a bit iffy and better to say UEFI when it's UEFI. And to say that a computer running a UEFI also runs and starts with a BIOS, as that article does, is completely wrong. The author of that article perhaps doesn't realise that UEFI includes even the 16bit part that runs very near the very beginning of booting.

That.. ^ And research I have done indicates that the linked article in the questoner's post is really wrong. UEFI does replace the BIOS. A computer runs either a UEFI, or if it's very old, then a BIOS. Sometimes colloquially the term BIOS is used for the configuration screen, but that screen is part of the UEFI and techies will often jump in and correct and say UEFI not BIOS. Some may use the term BIOS for anything run by the CPU before the boot loader, even if it is a UEFI, but it's a colloquialism and a bit iffy and better to say UEFI when it's UEFI. And to say that a computer running a UEFI also runs and starts with a BIOS, as that article does, is completely wrong. The author of that article perhaps doesn't realise that UEFI includes even the 16bit part that runs very near the very beginning of booting.

The article you link to https://wiki.osdev.org/UEFI uses strange terminology that nobody else uses like that.

I don't think the word BIOS would ever apply to anything as early as that! And UEFI wouldn't either.

The article you link to https://wiki.osdev.org/UEFI uses strange terminology that nobody else uses like that. So that article is saying BIOS runs first then UEFI, but that's not really the case.

(That article's terminology is neither of those, that article's terminology is way off)

So for now let's put aside that article's bizarre definitions of UEFI and BIOS and look at the definitions of UEFI And BIOS and how they are used.

I don't think the word BIOS would ever apply to anything as early as that! And UEFI wouldn't either. So when a source like wikipedia in its article on BIOS, says BIOS is "the first software to run when powered on", it's not technically correct, for two reasons. A)'cos even if a system was running a BIOS and not a UEFI, the BIOS still wouldn't be the first thing to run. B)And if a system is running a UEFI there wouldn't be any BIOS running!

Looking at that article and its unique strange wrong terminology

There is a colloquial definition of BIOS, and a technical definition.. That article is using neither.

The colloquial definition would be https://en.wikipedia.org/wiki/BIOS "the first software to run when[the computer/PC is] powered on" . and "firmware used to perform hardware initialization during the booting process (power-on startup), and to provide runtime services for operating systems and programs."

BTW there are things that take place when a computer powers on, before any motherboard firmware runs.. i.e. before it runs the 'reset vector' , here is some description of what happens before then, http://www.drdobbs.com/parallel/booting-an-intel-architecture-system-par/232300699?pgno=1 . (and the article continues for afterwards too)

By that definition(BIOS as a general term for motherboard firmware), a UEFI would be a BIOS / the term BIOS could be used to refer to UEFI. Some perhaps older sources, may have spoken of UEFI BIOS, to mean UEFI. For example this source written in 2013 https://www.alphr.com/features/381565/uefi-bios-explained speaks of a UEFI BIOS but rightly says it's not that meaningful and falls to the term UEFI , which is what it meant by UEFI BIOS. The Dr Dobbs link I mentioned from 2011 also uses the phrase "UEFI BIOS", to mean UEFI. Your source uses terms more strangely.

If one wants a general term for UEFI and BIOS then "motherboard firmware" is a good one, and technical / technically fine.

One attempt at justifying the suggestion in that article that firmware runs before the UEFI, was a claim that "CPUs start in 16bit mode. UEFI runs in 32bit or 64bit. So something has to get there first." (and they may the first paragraph of that wikpedia article on the BIOS and say it's that - the BIOS that runs first). But that claim can be proven wrong. One can point to the UEFI starting in 16bit.

That's the terminology used in that article and has some basis eg the wikipedia article on BIOS uses the term BIOS in the general sense, though it says UEFI is the successor to the BIOS. But the term UEFI doesn't project back in time to what preceded it. Whereas the definition of BIOS given in that wikpedia article could project backward or forward in time as it's defined there are the firmware that runs when the computer starts. So by that logic, one could say UEFI BIOS. Even though, as even that same BIOS wikipedia page says, UEFI is the 'successor'.

And whatever wiring/electronics gets the CPU To go to the reset vector is not BIOS or UEFI. https://stackoverflow.com/questions/22312428/what-memory-is-used-for-storing-the-reset-vector

That.. ^ And research I have done indicates that the linked article in the questoner's post is really wrong. UEFI does replace the BIOS. A computer runs either a UEFI, or if it's very old, then a BIOS. Sometimes colloquially the term BIOS is used for the configuration screen, but it's part of the UEFI and techies will often jump in and correct and say UEFI not BIOS. Some may use the term BIOS for anything before the boot loader, even if it is a UEFI, but it's a colloquialism and a bit iffy and better to say UEFI when it's UEFI. And to say that a computer running a UEFI also runs and starts with a BIOS, as that article does, is completely wrong. The author of that article perhaps doesn't realise that UEFI includes even the 16bit part that runs very near the very beginning of booting.

There is a 'colloquial' definition or usage of the term BIOS, and a technical definition.

The colloquial definition or usage of the term BIOS, is not just to refer to the BIOS as a BIOS, but to refer to the UEFI as a BIOS. That may be because they are using the term BIOS generally, or it may be they just call the UEFI, the BIOS, because they think the term is more familiar to people as BIOS was around for a long time and to the end user or even to most computer technicians, it looks the same. And they may even say UEFI BIOS, to mean UEFI. That may be because are using BIOS generally and see UEFI as a type of BIOS. Or they may be saying it because some may have no idea what a UEFI is and by sticking the word BIOS after it, they think it makes it clearer for people, as from the perspective of end users and most computer technicians they look the same. e.g. they have a configuration page, you can choose boot order.

https://www.howtogeek.com/56958/htg-explains-how-uefi-will-replace-the-bios/ "Even if your PC uses the term 'BIOS', modern PCs you buy today almost certainly ship with UEFI firmware instead of a BIOS. "

So, computers sometimes use the colloquial definition , for example it says push F2/Escape/F10/whatever to go to the BIOS. Or says Press whatever to go to setup, and then it says "BIOS version ..". Actually it's technically not a BIOS it's a UEFI.

There are things that take place when a computer powers on, before the processor executes anything. i.e. before it runs the firmware in the 'reset vector' , that's before any BIOS or UEFI. Here is some description of what happens then, http://www.drdobbs.com/parallel/booting-an-intel-architecture-system-par/232300699?pgno=1 . (and the article continues for afterwards too). There's a CPLD that is programmable, it runs software, that is firmware. That is very obscure. People almost never mean this when they say motherboard firmware. That firmware regulates the power supply and clocks and then lets the CPU reset and start.

I don't think the word BIOS would ever apply to anything as early as that! And UEFI wouldn't either.

When the CPU begins its fetch decode execute cycle, it begins with a part of memory known as the reset vector - which has or points to the BIOS or UEFI.

Some perhaps older sources, may have spoken of UEFI BIOS, to mean UEFI. For example this source written in 2013 https://www.alphr.com/features/381565/uefi-bios-explained speaks of a UEFI BIOS but rightly says it's not that meaningful and falls to the term UEFI , which is what it meant by UEFI BIOS. The Dr Dobbs link I mentioned from 2011 also uses the phrase "UEFI BIOS", to mean UEFI. Your source uses terms more strangely.

If one wants a general term for UEFI and BIOS then "motherboard firmware run by the CPU" would be spot on.

One attempt at justifying the suggestion in that article that the CPU runs some firmware before the UEFI, was a claim that "CPUs start in 16bit mode. UEFI runs in 32bit or 64bit. So something has to get there first." (and they may the first paragraph of that wikpedia article on the BIOS and say it's that - the BIOS that runs first). But that claim can be proven wrong. One can point to the UEFI starting in 16bit.

That's the terminology used in that article and has some basis eg the wikipedia article on BIOS uses the term BIOS in the general sense, though it says UEFI is the successor to the BIOS. But the term UEFI doesn't project back in time to what preceded it years before. Whereas the definition of BIOS given in that wikpedia article could project backward or forward in time as it's defined there as the firmware that runs when the computer starts(by which it means when the CPU starts). So by that logic, one could say UEFI BIOS. Even though, as even that same BIOS wikipedia page says, UEFI is the 'successor'.

And whatever wiring/electronics or even firmware, gets the CPU To go to the reset vector is not BIOS or UEFI. https://stackoverflow.com/questions/22312428/what-memory-is-used-for-storing-the-reset-vector

That.. ^ And research I have done indicates that the linked article in the questoner's post is really wrong. UEFI does replace the BIOS. A computer runs either a UEFI, or if it's very old, then a BIOS. Sometimes colloquially the term BIOS is used for the configuration screen, but it's part of the UEFI and techies will often jump in and correct and say UEFI not BIOS. Some may use the term BIOS for anything run by the CPU before the boot loader, even if it is a UEFI, but it's a colloquialism and a bit iffy and better to say UEFI when it's UEFI. And to say that a computer running a UEFI also runs and starts with a BIOS, as that article does, is completely wrong. The author of that article perhaps doesn't realise that UEFI includes even the 16bit part that runs very near the very beginning of booting.