BIOS and UEFI are two tools that basically do the same sort of thing. But they can be a little bit confusing when it comes to, how do
you know which one to use on a computer? And do I need to support one or the other or both? The nice thing is you usually either have
BIOS or UEFI.
Now, BIOS is an older program. And it just stands for Basic Input Output System, whereas UEFI is the new kid on the block. And this
stands for a Unified Extensible Firmware Interface, which sounds confusing. But really, it's just the way that we can interact
between the hardware and the operating system.
Now, let's say that we have two different vehicles. Now, these are two obviously very, very different vehicles. One of them is a
sports car. And one of them is an awesome yellow Volkswagen Beetle. I actually have a Volkswagen Beetle that's yellow like this.
And it's awesome. But nonetheless, you could be a sports car person. Either way, even though they're ridiculously different
vehicles, they both have some common interfaces, right? They're both going to have brake pedals. They're both going to have
They're both going to have windshields. And those interfaces are fairly common across all vehicles. Now, the brakes and the
underlying system are going to be different. This sports car probably has really nice disc brakes, whereas these old Volkswagens have
Now, drum brakes aren't as good. But the interface itself is very, very similar. You push the brake pedal, and you stop. And
that's what BIOS and UEFI are. They're interfaces between the hardware and the operating system itself. Now, they do work a
little bit differently.
So here we have our hard drive on our system. Now, using BIOS like the old method of booting a computer, you would have the very first
sector on the hard drive would be the boot sector. And that's where the MBR, the Master Boot Record, would live. And then that
would tell the computer where the partitions are and point it to where to boot.
Now, there's a lot of limitations with BIOS. You could only have four partitions using the BIOS and MBR combination. There are some
hacks to get around that. They would take a partition and do extended partitions inside that. But that's a whole other Nugget.
Still there was this limitation. Also, a limitation of size with the drive, how much this boot sector or this Master Boot Record can
actually reference. It can be a small amount, like two terabytes instead of exabytes of data. And so UEFI is a replacement for the BIOS
And rather than just have the single boot sector, what it does is there's an entire partition on the system. And that partition is
where all of the boot code is for whatever operating systems might be on the computer. So rather than just the boot sector pointing to
the rest of the hard drive, this is an actual specialized partition on the computer.
And that's where the UEFI code is stored. Also, it uses a different partition scheme. So you can have tons and tons of partitions.
And it can address a much larger hard drive. There's also other things like Secure Boot that UEFI supports that BIOS doesn't.
Basically just know that UEFI is the replacement for BIOS. It replaces the functionality of connecting the hardware to the software of
the operating system. Now, the good news is if you have a computer that's older-- or even some new ones still come with BIOS-- you
can still get around a lot of the limitations, because there are hacks that will let you use really big hard drives or hacks that will
allow you to do some of the things that you can't normally do out of the box.
But most computers now are coming with UEFI. And from an installer point of view, there's very little you have to do, because the
operating system is going to say, OK, I was booted using UEFI. So I'm going to create a partition, a UEFI partition. And I'm
going to put all the boot code in there.
So from your standpoint, from the end user or the installer standpoint, there's very little difference. But under the hood, a lot
of new, cool stuff is going on. And that's why UEFI is the way of the future. Hope this has been informative for you. And I'd
like to thank you for viewing.