Swapping/Changing OS's?

[MeesterJackson]

I've always wondered about this, but could you essentially lets say....take Linux or another free OS (maybe even Steam's OS) and buy Windows and install it (I'm assuming it would then tell you to uninstall whatever OS you were currently running at this point) and then have whatever version of Windows that you bought run on your system just fine? 

[yttrium]

Alright, I assume you're a bit of a newbie when it comes to partitions and operating system installations, so give me a second here to write up a proper reply explaining how everything works. Before I do though, yes, it's possible.

 

EDIT: Let's begin with what a partition is. I'll use a very simple analogy. Assume a hard drive is a plot of land. Let's say, for instance, that you buy a 3TB hard drive - that's 3 acres. Now, say you want to divide those three acres into three same-sized fields. You then have to create two fences dividing the 3 acre plot into three separate sections. Those sections are called partitions, and in this analogy, you now have 3 1TB partitions on your 3TB hard drive.

 

Let's say you want to install Windows now. You decide to install Windows to the first partition, the first field. It unpacks all of its data in that 1 acre that it's allowed (1 acre is actually really small considering the data sizes we're talking about here, but for the sake of simplicity, let's keep using this ratio). It only ends up taking about 20GB of that 1TB field - about 1/200th of the overall acre. The rest of the acre is free for you to install programs, save files and documents, etcetera.

 

Windows stored all of its files using a certain structure, a pattern. This is called the filesystem. Windows uses NTFS, the "New Technology File System". All of the data in field 1, the first partition, is stored in this format. Windows can only read NTFS, FAT/16/32, and ReFS (new in Win8). It can only boot from a partition formatted in NTFS, but it can read all of the previously stated ones. So, say for example you format the second partition, or the second 1TB allotment, as ReFS. Windows is not installed here, and so you can't boot from that second field, but if you boot from the first one, Windows can read from the second one on top of the first one. In Windows, you would now see two drives in Computer: C:, or Field 1, and D: (by default), or Field 2.

 

Now, we decide to install Linux. It gets installed to the third field, partition 3. It uses the file system "ext4", which is a fairly standard Linux filesystem. Many other operating systems can read it, but Windows cannot, so when Windows is booted, some low level programs might be able to see that there's a third filesystem on your hard drive, but they won't be able to read the data from it because they don't know how to understand it. Linux, on the other hand, does know how to read NTFS and ReFS, so while Linux is booted, it can read from Field 1 and Field 2, on top of its install on Field 3.

 

You now have Windows installed on Field 1, and Linux installed on Field 3. When you turn on your computer, normally Windows will just boot itself and ignore Linux. You can't override this unless you replace the bootloader.

 

The bootloader is a special section of data at the very beginning of the hard drive, literally only a couple of megabytes. This section is called the MBR, or Master Boot Record. When a bootloader is installed here, it is the first thing to start when the hard drive is selected as the boot device by the BIOS. The Windows bootloader just boots Windows unless instructed to do otherwise, but it usually can't boot Linux even with a vast amount of tinkering.

 

To circumvent this, Linux developers came up with another bootloader, called GRUB - the GRand Unified Bootloader. GRUB will replace the Windows bootloader if one is installed - only one bootloader can be installed at a time, and GRUB can boot Windows as well as Linux and pretty much any other OS.

[Firearm2112]

Im kinda confused on what your asking

[FizzyFantom]

You can install any OS any number of times on any drive, including installing Windows over Linux or the other way around (assuming the drive still works obviously) if that is what you are reffering to.

If you are asking about multi-booting a PC with several different operating systems then it is definitely possible. I recommend you install any Windows installations before Linux as Windows doesn't like to be installed onto partitions as opposed to whole drives. With an OS like Ubuntu it will have an option to install alongside Windows if it detects it during the setup and it will allow you to choose the size of each OS partition. You can use GRUB to boot several OS on a single PC including various Linux and Windows installtions (which is what Ubuntu uses when installed alongside Windows).

[MeesterJackson]

Alright, I assume you're a bit of a newbie when it comes to partitions and operating system installations, so give me a second here to write up a proper reply explaining how everything works. Before I do though, yes, it's possible.

I've just never really thought about it, I typically buy or tell a friend to buy Windows, I install it through a disk and boom. That's it. Now that I am sort of in a bit of a crunch with my budget for my own PC I've come to realize that I seriously hate how much MS charges for Windows. I'll still use their OS, just if I can't afford it from the start because I want a specific item in my build, then I'll have to use a different OS that is going to be most likely free. 

[MeesterJackson]

You can install any OS any number of times on any drive, including installing Windows over Linux or the other way around (assuming the drive still works obviously) if that is what you are reffering to.

If you are asking about multi-booting a PC with several different operating systems then it is definitely possible. I recommend you install any Windows installations before Linux as Windows doesn't like to be installed onto partitions as opposed to whole drives. With an OS like Ubuntu it will have an option to install alongside Windows if it detects it during the setup and it will allow you to choose the size of each OS partition. You can use GRUB to boot several OS on a single PC including various Linux and Windows installtions (which is what Ubuntu uses when installed alongside Windows).

I believe it's the first thing. I want to purchase Windows, however if I really want a certain part in my new PC build, then I'm not afraid to skip over it for a free OS for the time being. 

 

So IF I did that, and lets say downloaded Linux onto my system and waited a couple of months, then bought Windows 8.1, could I just install Windows 8.1 normally (while deleting Linux) without the data on my system needing to be completely wiped or something?

[MeesterJackson]

Im kinda confused on what your asking

How? 

[FizzyFantom]

I believe it's the first thing. I want to purchase Windows, however if I really want a certain part in my new PC build, then I'm not afraid to skip over it for a free OS for the time being. 

 

So IF I did that, and lets say downloaded Linux onto my system and waited a couple of months, then bought Windows 8.1, could I just install Windows 8.1 normally (while deleting Linux) without the data on my system needing to be completely wiped or something?

In that case you can install Linux (I recommend Ubuntu or Mint) at the start then install Windows later. If you opt to install Windows over the whole disk then you will lose your data, but you could make a second partition on which to put your data so you won't lose it (although you should probably back it up before you install a new OS anyway).

[yttrium]

Edited my first reply with a lengthy explanation.

 

So in essence, you want to use Linux at first, and then later wipe it and install Windows but retain your data.

 

I would suggest creating a 1TB ext4 partition with Linux, and a 2TB NTFS partition for saved data.

 

Then, when you wipe the original 1TB partition and install Windows over it, you'll still have your 2TB data partition for your own personal files. They'll be intact and can be read when you're in Windows.