From the course: CompTIA A+ Core 2 (220-1202) Cert Prep

Boot order

From the course: CompTIA A+ Core 2 (220-1202) Cert Prep

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Boot order

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- When you fire up your system, the first thing it does is a power-on self-test. But once it does a power-on self-test, it's going to be looking for a storage device with an installed operating system from which to boot. So in this episode, I want to talk about the boot order in particular on a system where you have lots of storage devices. So let's take a look at the system I got here. So starting way over here, I've got a couple of traditional hard disk drives. Now, really close to me right here, I've got a two-and-a-half-inch SSD. And then coming down here in front of the SSD, this is optical media, which, by the way, just uses a regular SATA connection like any other SATA device, no big deal there. And on top of that, I've got an M.2 on the other side of this motherboard. But if you look here on the very, very top, you're going to see I've got a USB thumb drive. On this one system, I've got two hard disk drives. I've got one SATA SSD, I've got one M.2 SSD, I've got optical media, and on top of that, I've got a thumb drive, a total of six mass storage devices. Now, the challenge we run into is, which one do I want to boot from first? Now, if I only had one single mass storage device, this would be easy. I would always want to just boot off of that. However, there are lots of scenarios where we need to set a boot order. For example, I might have some anti-malware tools on that thumb drive. And whenever I shove that in, I don't want it to boot off of its regular Windows M.2, I want it to boot off of that. Or maybe I snap in a CD-ROM or a DVD that has some utilities and I want to boot off of a Linux live CD to do something. I want to boot off of that and not off the drive. The bottom line is, is that when you have a lot of different types of storage devices, you have to define the boot order. And the place that we define that boot order is in our system setup. Now that we're in the system setup, the first thing I want to do is make sure that the system recognizes all of these storage devices. Now, every system's going to be different. On this one, it's actually fascinating, it's all graphical. So I'm going to go into this board explorer and it actually shows a picture of my board. So right here are my six SATA connections, and you can see the four that are highlighted. This is how it tells you there's something plugged into it. Whoop. So I can actually go here. You see it says BC-12B1, whatever that is, that is my optical media. And I had to do a little research to find that one. Here is the SATA two-and-a-half-inch. Here's one of the hard drives, and then here's the other one. So four of the devices are right there. So I'm happy about that. Now, the other two things we have to worry about are the M.2 and the thumb drive. So now that I know that red means something's plugged into it, I'm going to look at this M.2 slot, and you can see it says straight up Samsung SSD. That's my M.2. So the only one left, and I got to be honest with you, I had to check this before we tried it here. I had to find that thumb drive and it was not obvious, but I had to go here. And on this particular dongle connection, which I'm not really plugged into the dongle, I use this connection for my front connections, it shows my USB disk. So, okay, so the system recognizes all of these devices. So what we're going to have to do for starters is we're going to have to pick a boot order. Now, we've got this groovy little graphical thing, which is actually kind of fun. And on this particular board, it wants to try to boot UEFI mode. And then you will see these without the U. That is a more traditional mode. There's really no big motivation for me to boot UEFI because in most cases I'm installing an operating system. And the operating system itself, once it loads, will kick over and force UEFI mode. So we can take a look at what it wants to first boot, notice the red outline. These are devices that it actually sees, so it wants to first boot to my thumb, which is pretty standard. Then it wants to boot off of my M.2. Then it wants to boot off of the optical media, and then it wants to boot off the thumb drive again. But in a more primitive mode, you'll notice that some of the devices don't show. That's because on this particular motherboard, it's going to want to do these M.2s or optical media before it's ever going to go down to old school hard disk drives. So we can go into boot and you can see the order that it wants to boot everything. Now keep in mind that I've just plugged a lot of stuff in. UEFI requires a special ID. So a UEFI-capable device, like, for example, a bootable thumb drive or a hard drive that already has Windows or Linux or something like that on it. When I boot up the system, the system setup sees this and would recognize them differently than how it's recognizing them right now. But anyway, this is my default boot order that I want. If I want to, I could turn off the old legacy devices completely and go just straight to UEFI. I would not recommend this. A lot of optical media, a lot of old hard drives will still want to go into that older mode. So whatever the case may be on this particular one, this is actually kind of fun. Here, if I want to boot off of my optical media, let's say I have a Windows-boot optical media. It's graphical. I can just push this to the front and no matter what, it's always going to boot off of my optical media first. Or if I always want to boot off of my thumb drive first, I can go ahead and just set the order. You can actually see it changing here as we go about it. Boot orders are absolutely critical. You're going to see plenty of scenarios both on the exam and in real life where somebody has put a thumb drive onto a system and suddenly they think they're in a Windows computer and they're booting to Linux. There's nothing wrong with your computer, folks. It's just that the boot order said boot off of the thumb drive before it got to your Windows hard drive. So when we're talking about boot order, the most important thing to remember is take your time, go into your system setup, check who's who in the zoo. And don't be surprised if the occasional thumb drive or optical media boots you into a place that you'd never ever anticipated.

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