What is multi-boot?

courtesy of a little listener mail. This listener mail comes from Jeff and Jeff says, Hey, Chris and Jonathan or the unfortunate intern who must sift through listener mail first. Uh no, Jeff, that's us. I am absolutely in love with the podcast. I just finished listening to your show on Hackintosh's and the unfortunate comment at the end of the show about sticking with a PC if you want

to do the useful things. I love my Mac, but I do have to agree I miss gaming too, which is why I used Apple's boot camp to install Windows XP on my Mac, resulting in a to the dual boot system. A delusion. Questions is about to begin. How the heck does it work. Boot Camp is provided by Apple as if they're encouraging people to also install Windows on their max. Of course, you still have to purchase your own copy of Windows. Is that a violation of

the you love for either Apple or Microsoft? How or why did Apple make their machines compatible with both operating systems? And then how do other programs like Parallels, which allow you to operate Windows while running your Mac work? Keep up the great work. Jeff ps. A show on green technology would be awesome too. I would not complain about that. We're not doing a show on green technology. No. Today,

we're doing a show about multibooting. Yes, because your computer will depending on your computer, but we'll get in a second. Your Peter may or may not be able to run multiple operating systems, not just you know, for example, Windows and Mac. As you said, right, yeah, we when we're talking about multibooting, it's uh, it's it's a wider net than that. We're talking about things like a Lenox, Unix things like that, not necessarily all of them at the

same time. Some of them work together and some of them don't. Um And when we say work together, we'll have to get into that a little bit. Too. It's kind of, um, it's kind of an unusual situation. So when you turn your computer on, right, and I'm talking about like when you flip the power switch, and I'll talk about when you buy it chocolates and say nice things to it. Uh, there's a certain process that the

computer goes through in order to boot up. Now, this process starts with the master boot record, Yes, which is a sector at the very very beginning of the hard drive. Right, so your your computer's hard drive, whatever format that might be in. It could be a platter hard drive or it could be so its state, but either way, within that first sector, there's something called the master boot record.

Now this is this is the the little bit of code that tells the essentially your computer where to go next, like how how how to boot up the operating system. So the uh, what I'll do is it'll it'll reference a partition table and look for the active boot partition. This is what then says, okay, well you know, if we've passed go, here's the next square that we have to move to. So it passes the control to the

partition boot record that continues the booting process. Now, the partition boot record then looks for a system specific boot files that are associated with that particular operating system. Right, So the like a Windows that would start looking for the I and I files. Um. At that point, it then finishes the whole process of boot it ing, and it loads up the operating system for your computer. Now, if you only have one operating system on your computer,

this is a very straightforward process. It's just a straight shot, right. Yeah, So NBR for the master boot record, NBR to the PBR, which is not perhaps blue ribbon that several people listening just thought that, Yeah, I know, um, but no, the that's the the partition boot record, and then that goes to the system files. So uh, pretty pretty straightforward. However, the interesting thing about computers, or one interesting thing about computers, Yeah,

it turns out there's more than one. One of the interesting things that you can learn about computers is that you can install multiple operating systems on a computer if you partition the hard drive correctly. That's true. Well, there is an alternative. You could have multiple hard drives, each with its own operating system. That's a little bit more I should point out to Ouh. There's a lot of

detail that could go into a multiple boot system. So we're not We're probably gonna take just a really high end look at it, because we're talking about the the basics here to see behind. As it turns out, depending upon which operating systems you want to install, there are a lot of different things you have to take into consideration.

For example, some versions of Windows can recognize when other operating systems are installed on your computer, whether or not that is the whether or not that that version of Windows is your primary operating system. Some of them object to not being the primary operating system, and if it's not the primary, you're gonna have more headaches. You're gonna there are ways of working around it, but you have

to find out what those ways are. Um, it's so, Yeah, it can get really really complex, so we're gonna try and keep it more general. In most cases, you can find tools out there that make this fairly easy, or at least easier than if you were to set out and do it on your own. Yep, there's a so, so it is possible. Getting back to what you were saying before, Jonathan about um, you know they're being partitions on a drive. You could have multiple drives with multiple

operating systems. But let's say you're you know, the average person who is interested in a dual boot system, or you know, in the case of our dear listener, someone who has, uh, you know, the opportunity to install multiple operating systems on one single hard disk. And in that case, yes, you do want to partition your hard drive. And a partition is pretty much exactly like what it sounds like.

It's it's a different part of your hard drive. Um. And when you partition you're hard drive, you're basically telling, uh, your computer, look, this part of the hard drive is like its own hard drive. Your It's not literally a different hard drive, but your computer treats it as though it were a different hard drive. Right. So, if if you want to think of it in physical terms, although I should hasten to add that the physical representation is is it's just an example. Um. The physical nature of

hard drives is also a very complicated thing. As it turns out. You talk about cylinders and platters, and then there's solid state drives, which are a different animal altogether, and by animal, I mean hard drive. Don't write meat people, um. But if you want to think of it in physical terms, think of a room and you've got a pretty big room. No, it's it's it's roomy in fact, and there's a you know,

it's a nice square room. And then you think, you know what, I want to set this one corner of the room off to be a room where I store all my stuff. It's gonna be essentially a closet. So you build a couple of walls, um, and you you you partition off that room. There's still a door into the big room, so you can get back and forth, but it's set aside. And then you think, hey, you know what, I've got that place to store my stuff.

But I really want I want I want a special corner here so I can watch movies and play video games and stuff. So I'm gonna build another wall and uh, and I'm going to corner off this section here from the main part of the room. Well, that's essentially what you're doing. When you're partitioning off a hard drive. You are taking up the whole and you're dividing it up into parts. Um. These parts, of course have to be smaller than the whole. We can't magically make our hard

drives larger than what they were before. Uh. And in fact, this caused some issues back when hard drives started to bump up against the eight gigabyte range, because before that there was a physical limit based upon the hard drive architecture that a gigabytes. That was that was as high as you were gonna go. And we got around that, but almost like by tricking the computer um at any rate, So you can partition off your hard drive that way.

If you wanted to install more than one operating system on your computer, you would need to have a partition, at least a partition per operating system. So if you had to operating systems, you would need at the very least you partitions. You may want to do more than that. You may want both operating systems to have access to

the same data. For example, let's say that you have two different versions of Windows that you want to run and and there may be reasons why you would need to do this, and we'll get into that in a little bit, but if you had these two different versions of Windows, but you want to be able to access the same general data, you would need a third partition that would hold all the data, and both of your operating systems would have to be able to access that partition.

While maintaining separation between the two operating system partitions and the flowers are still standing. Yes. Nice, that's a ghostbuster's reference. Um. It took me a second to put it together. But yeah. So let's say that you've partitioned your hard drive. Would there are many tools out there that allow you to do this. By the way, before you partition anything, before you ever try this, back up your hard hard drive, and I'll tell you it's it's um, it's a good idea. Actually.

I read people who are you know, who are writing tutorials on how to create a multi boot system or to partition or hard drives, and one of the first things that they say, other than back up your hard drive, is maybe you don't necessarily want to do this with your main computer. Yeah. Yeah, I would avoid doing this with your main computer. If you have a secondary computer, that would be all right for you to play with.

But um, there are problems that can come up from partitioning your hard drive if things, especially depending on the the combination of operating systems you've chosen. Um, and don't just do it willy nilly. I mean, if you're willing to accept the risk, you know, go right ahead. But just keep in mind that there is a possibility that you could, um, you could erase a lot of information right that term paper that you have do on Friday, that you just got your second draft done and oh

don it now it's gone. Yeah. Um. And keep in mind also that operating systems can have is uose with different parts of your hardware. Um. Things that work fine in one operating system may stop working in another because the drivers aren't there. That's true, you should um. Not all operating systems are are created equal. As a matter of fact, This answers one of one of the questions. UM, because we were talking about what enables a Mac to

do this now when you couldn't do it before. Okay, so before um, when they were running these power PC chips, Uh, the operating system for Windows would just not run on it. So you were you had to make a choice if you wanted to buy a Mac, you ran the Mac os. UM. Well, when Apple decided to change course and switched over to Intel chips, Um, they are essentially the same chips that go inside a PC. Actually they are the same chips

because they will run Windows. UM and uh. And yes, to answer the other question, Apple is okay with you UH using bootcamp to partition your hard drive and install a copy of Windows on there. And of fact, it's a selling point for them right right because before you

know you you it was a macor a PC. Now you can do both, and that makes the Mac more valuable to some people because they can run programs from with operating Because what's interesting is you can't do it the other way around, or at least Apple doesn't want you to. You can do it, but in order for you to be able to run the mac os on a PC, you have to essentially fool the operating system into believing it is on a Mac. Yeah, it would

have to. UM, the Mac is going to have to recognize the components inside the machine, and if it looks like it isn't Mac, it's not going to want to run on it. Yeah. Now, again, you can fool the operating system using various kinds of software in order to UH to force it to run on a PC. But your mileage may vary as far as how reliable it goes. So getting back to to the whole multibooting concept here. Now we've partitioned our hard drive UM several times, we

know that it's going to work on that computer. Right. Yeah, Well, let's let's assume that we have already taken into account the different operating systems we're going to use. Let's go ahead and say we're running, um, two different versions of Windows and a version of Linux. So we have three different operating systems on this one machine. We've got let's

say five partitions total. All right, So each partition for the operating system you've you've created it so it's just big enough to hold that operating system, all right, So that means that but you could do it, But you could do you could do it where each each one is maybe give it a little room, but more or less, what you've got is a partition that's large enough to hold each operating system. And then you've dedicated the rest of your space for storage right in your in your

two different drives that you're using for storage. Now, um, when you boot up the computer, depending on how you set up the master boot record, because this this different vendors do different methods. Actually Microsoft is very different from everyone else. But if you were to uh, for the most part, what happens is when you boot up, the first step is the same. The master boot record looks at the partition table, only this time there are choices.

It is no longer, oh, I need to hand over the booting power to this very particular uh PBR again not perhaps blue ribbon, the partition boot record. I can't just do that because there are multiple choices. And then what will happen is you'll be presented with the choice of which operating system you wish to boot into, right, and so you choose that one, and then the rest

of the process pretty much is the same. So the the NBR will hand over the booting to the PBR, which then moves forward from there and and accesses the appropriate system specific boot files in order to to start up the operating system. So with Linux, it's going to be one set. With whatever version of Windows you're running, it's going to be another set. And then of course your your second version of Windows will use yet a third set, so um you could choose any of those three.

You have to remember that this is divvying up your computer's resources, so your computer is not gonna have nearly the amount of storage space that used to have. UM it can also depending on the operating systems you've chosen, it can affect performance in other ways. Um, it could make your computer run a little more slowly. Uh. Depending on how you've partitioned the drives, it may have more trouble accessing the hard drive in order to find the

right information it needs to operate. Um. It's a tricky thing, which is again another reason why it's a good idea to use this on a secondary or or you know, even a tertiary machine or whatever. You know, some spare machine you have as opposed to your primary one, just because if stuff goes wrong, then you haven't lost all. You haven't lost your your primary machine. Yeah, if you're already,

If you're partitioning machine, that's I'm sorry. If you're partitioning a hard drive on a machine that has uh um been formatted. Say you have a a Windows XP machine with a five gigabyte hard drive, and you've had this machine for two years now, and you say, you know what, I'm ready to try Linux. I want to install Linux on here. I want to partition my hard drive. Well, UM, you're gonna have to sort of be very careful because

the information on there. You know, of course, you probably know about defragmentation, how data can get stored in different sectors on a hard drive, all over the hard drive. But what a partition is gonna want to do the partitioning tool, it's gonna want to create a part of the hard drive that doesn't have any information on it. And so you know, you have to try to judge how much room you want to save on the Windows partition, like, well, how much am I gonna how much space am I

gonna need on there? How much? You know, am I going to run the risk? And it warns you if when I installed UM it won't two on our test machine here in the office. It warned you. It says, you know, look, there is a possibility that some of your files could be damaged in this process because it's already formed at it And are you sure you really

want to do this? And I'm sure it's just a precaution, but so you know, just be aware that formatting a hard you know, that's why we were sort of talking about the idea of starting from scratch, you know, brand new hard drive. Let's go ahead and throw three different

operating systems on there. You know, if you're doing this with a hard drive with an operating system that's been on there for a while, you know that information is going to be spread out a little bit, you might want to run a defragment or on it and clean up to drive a good bit before you partitioning. Yeah, if you don't, if you don't mind the idea of totally wiping your computer and starting from scratch, then that

that solves a lot of problems. But as we as we mentioned Chris, that was a really good point because, like I said before, with the physical representation that room, where you you easily block off a corner here, in a corner there, that's not the way it really works on a computer. On a computer, you could think of it as a high rise building with lots and lots of different rooms, and certain rooms have their lights on, and other rooms have the lights off, and the rooms

that the lights off, those are those are free. You can use those too put in more information. But they're scattered all across the building in different levels, and and some levels have almost all the lights off, and some levels have almost all the lights on, and others are are kind of a jumble. Um. That's why it's kind of that this can get really complicated because to partition off, say all right, well, I need a block of sixty

rooms that have no lights on. Uh, there may not be an adjacent block of sixty and may be spread across. So again we're talking about a difference between the physical structure of the hard drive and what the actual digital representation is. Which is why the more I read about this, the more my head hurts, because I was an English major. Well, thankfully, most of the utilities now for the most modern operating

systems that will help you with this. You know, things like g parted, which is a a free, open source UM utility UM and of course boot camp for the Mac. They'll help you through it. They'll walk you through it. If you're installing UM, I know most flavors of Linux have you know, when you're installing the computer it it helps you walk you through the process of doing this.

Do you really want to partition your hard drive? You can that way you can install you know this along with your normal operating system or would you prefer just to wipe the whole thing clean? Um? So, thankfully it you know that you get some help, but UM I recommend to if you're if you're doing this as a hobby and you're especially if you're really concerned about the possibility that you're going to do damage to the data

on your hard drive by doing this. I recommend doing a little research on the internet first before you do this with some reputable sources because UM, it really differs operating an operating system and version of operating system to version of operating system. UM, there are some details that you might want to pick up on, and we don't. You know, there's a lot. I wanted to make sure that everybody knows that this is you know, it's not it's not really hard to do, but you want to

be careful when you're doing it right. Each each pairing has its own set of circumstances. So that's why we don't really go into detail because to do to say, like you want to run Windows and Windows Vista on the same machine is going to be totally different. And if you want to run run Windows XP and Lennox on the same machine, it's just it's it's come you know, there are different set of parameters that you have to

take into accounts. So but they're fortunately, like Chris said, there are a lot of resources out there that pretty much cover every single variation you can think of. And UM and and if it's not covered. You can probably find a forum somewhere where you ask a question and people will be quick to answer you. So it might even get you involved a little bit more in the community and you'll, uh, you know, maybe you can become

more of a contributor and hobbyists. Um. And I was going to add to talking about the complexity of it. One of the reasons I didn't really want to get into the multidisc a physical hard disc setup is because it involves wiring. You have to, uh, you know, tell each hard drive whether you know you have to pick a master hard drive and then indicate which ones are

slave hard drives. Um. And it's you know, you're better off going through the instructions and actually consulting uh some experts before you get started with that, because it's it's it's more detail than what a podcast can go into, really yea. Um, but I was also gonna meant we were going to talk about why people might want to partition their hard drives and make a multi boot system. Well, first of all, before we even get into multi boot,

you may want to partition your hard drive. I mean, one reason you might think about doing it is just for an organizational standpoint. So you may only have one operating system, but you might want to partition your hard drive into multiple UH drives so that you can store certain information in one drive and other information and another drive. UM. This can depending on how you organize, it can actually

speed up things like retrieving information. If you're using a like a video processing program, and you you've put all of your video stuff into one drive, then eventually the operating system it knows it's just gonna go to this one drive, which is much smaller than the overall hard drive space, doesn't take it as long to search up particular information and pull it back for you, so it can in certain cases be faster to partition your hard

drive and retrieve information that way. UM. Or you know, just from an organizational standpoint, if like you wanted to have a drive just for all your games and then everything like all your other data was going to be on another drive. UM this also helps if you ever have a if there's ever like a corrupt disc or something. If something happens that that corrupts one of your drives,

your other drives might be safe. And if you keep backing up your drives, which you should be doing, then you can do a restore that hopefully won't affect your entire computer. It just affect one drive, which still is pretty traumatic, but it's not as bad as the entire computer having to be restored. Yes. Now, for as for multi operating systems, why would you want to do this? Well, you know, we have one example, yes, um, and uh

you know there are other reasons too. For example, in our office we have the test machine, which you have heard about very frequently. We were trying both Windows seven, the beta version of that before it went before it became stopped working. It still works for two hours at a time and shuts down without telling you. Uh you know, since we haven't yeh Um, we'll get around to that eventually,

and uh one to UM. And it gives us an opportunity to try both operating systems out on the same machine without having to uh you know, we don't stall an additional drive. And it give us a chance to

actually try out partitioning a hard drive. UM. But yeah, I mean, if you're a hobbyist, you can you can certainly do that and uh you know, well, the way I figured also is that if you are let's say you're developing UM software, it might be it might be good to be able to do this so that you can make sure you develop software that works on different operating systems or different versions of the same operating system, because you may want to even do this with the

IS like the mac os. You may want the different versions of the macOS on one machine so that you can make sure that things that run in in Leopard run in snow Leopard UM without having to purchase a machine per operating system, which gets pretty expensive. UM. And things like legacy programs. We've talked about legacy programs before. These are the old programs that that people and corporations depend upon that are no longer supported by newer versions

of the OS. They just you know, either the developers who originally created the software moved on to bigger and better things, or it's just abandoned ware or whatever, but there's no way of running that software in the modern operating systems. You may want to have a machine running the old system UM so that you can run legacy programs, but a lot of companies don't want to, you know, waste a machine just to do that. I mean, if that's all it does, then that's kind of a waste.

Of space and energy and all that kind of stuff. But if you are able to to dual boot it so that you can run it in, you know, the operating system that the rest of the office is running in for most of the time, and then switch over whenever you need to use the legacy program, then that might make sense. Now, one disadvantage to using a multi boot operating system is that if you want to use the other operating system, you have to restart and boot

into the other operating system. So you're in operating system A operating system B operating system, see, you know, and not sharing the others, which is the advantage of a program like Parallels or vm ware or Sun's Virtual Box. These are creating virtual machines where you can switch back and forth. Basically, it's it's like you see a window.

For for those of you haven't tried it, um, it's like you have a window open in your current native operating system, and inside that window is the other operating system that can run programs installed on it. And uh, it's you're not creating a partition, and well, it's sort of creating a virtual partition really when you think about it, right,

but not a physical part not a physical partition. UM. And uh it's kind of cool because you can say, you know, I actually have virtual Box installed on my Mac at home and a run uh Windows seven for two hours at a time on it, and uh, you know, I can I can switch back and forth from the Mac to the PC, you know, in the same window.

Now the problem is, UM, in this case, you're dividing up the resources very literally, because when you install a new operating system in this virtual machine and create a virtual machine to run that operating system, it asks you how much memory? And we're talking RAM here, not hard drive space. So I have let's say two gigabytes of memory on my machine. I have to decide, well, one operating system is gonna run let's say one gigabyte, Well,

the other one's gonna run the other. And so it overall your performance is going to be a little bit slower. And you know, it's not exactly like an emulator, but it works sort of like that. And you know, because you are running the other operating system concurrently, it's dividing up the system resources between the two. So everything is kind of delayed. Yeah, So if you have a really lightning best machine, then that's not gonna matter as much to you. But if you are, yeah, it's still gonna

be noticeable. But if you have a slow machine, then it could become painful. So there there are advantages to that if you have something very simple that only runs in the other operating system. You why I want to go that route, But um, if you really want, if you're gonna do something like play games, you know, the high end windows, high frame rate games, you know, first person shooters especially that kind of stuff with a lot of action, you're not gonna want to try to do

that through a virtual machine. You're gonna want to do you know, dual boot and flip over together exactly, exactly. Well, that was a good discussion about a multibooting. Yeah. Um, we're running a little short on time. I'm not going to go on into listener mail, but we will. We definitely read every single one of those messages, so we don't have an intern reading those, it's us. It comes

straight to us. Um. Sometimes it actually takes a detour to our junk folder for some reason, even though they're all coming to the same address. But we do make sure we check those as well, so keep those messages coming in our addresses is tech stuff at how stuff works dot com. You can read all about various operating systems at how stuff works dot com and check out our blogs are blogs at are at blogs dot hou

stuf works dot com. We've got lots of interesting things to say about all sorts of stuff there, and hopefully you guys found this to be a pretty interesting topic. It's uh, it's kind of cool to think about being able to run various operating systems on a single machine. Yeah, it's it's It's been kind of fun doing that on the test machine just to get a look at the other ones. So I like it because it lets me

break twice as much stuff on one single device. Indeed. Well, guys, hope you enjoyed it, and we will talk to you again really soon for more on this and thousands of other topics. Is it how stuff works dot com, and be sure to check out the new tech stuff blog now on the house stuff Works homepage. Brought to you by the reinvented two thousand twelve camera. It's ready, are you