Ubuntu is a super popular operating system. It is very customizable thanks to the theming options it offers and it is concidered to be more secure when compared to the other operating systems. For many developers and power users, their journey on Linux starts at Ubuntu. In this guide, I am going to show you how to install Ubuntu and Windows side by side on a BIOS or Uefi-based computer. The technical term for this is called "Dual Boot" and this comes super handy when you want to use Linux, but still don't want to lose Windows. Windows and Ubuntu each need at least one separate partition on the hard drive. If Windows used to take up all the space, you have to shrink the Windows partition. However, at least 20 GB should be free and available, better more. This is approximately the storage space that an Ubuntu needs for basic use. It is optimal to use a second hard drive for Ubuntu. To install Ubuntu, you need to a USB flash drive to contain installation files. You also need a bootable USB device creator software like Rufus to make it bootable.

With this, you can set up both systems completely independently of each other and do not have to change anything when partitioning. An external hard drive or a sufficiently large USB flash drive is enough for this process. But it should be at least one USB 2.0 flash drive. USB 3.0 would be better and faster, but not every motherboard supports booting via USB 3.0. To verify this further, you may have to check your motherboard's manual. 

Before starting this process, please make sure to backup all of your important data. We need a USB flash drive for this and make sure to backup the data on that drive too. I always start with this option because if something goes wrong you can go back to where you started without any hassle. 

  • As I mentioned earlier, you need a software like Rufus to prepare your installation media. Thefore, first of all download Rufus from their official website and install it on your computer. Then download the .ISO file of your preffered Ubuntu version.
  • Plug the USB flash drive into your computer. Make sure that it doesn’t have anything important on it that you want to keep because it is about to be fully formatted.
  • Rufus software is used to copy the Ubuntu .ISO image to a USB drive. Open up Rufus. Once you launch Rufus, you will see the following Windows. Locate the .ISO file using Rufus and once you are done all you have to do is on click “Write”. 
  • Now, the files will be copied to the disk and you will be able to use it to boot Ubuntu in a live environment. Once the process is done, Rufus will notify you about that and you can the USB flash drive plugged in and restart your computer.

If your BIOS boot order is in the correct order, it will boot via your USB flash drive. You will be presented with the installation window of Ubuntu and you have to follow the instructions to install it. When doing that, make sure to select a different partition to install Ubuntu. Now your computer supports dual booting. Once the installation process of Ubuntu is completed, to start and boot into Ubuntu, hold down the Shift key while logged in to Windows. Restart the computer while holding down the Shift key and you will be logged in to Ubuntu.

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