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I have 4 hard drives connected on my computer, 3 SSD and 1 HDD. One of the SSD contained Windows 10 OS and the HDD is actively used to store large applications for the Windows OS, and the other SSD is for Games. This leave me with one SSD 120GB that I plan to install Ubuntu 21.04 on. I tried installing ubuntu previously and found out that if I do default Ubuntu setup, Ubuntu bios bootloader and GRUB will be installed the Windows' SSD. I do not want any Ubuntu file or dependency stuff installed on it. So, My questions are

  1. If I do this, Can I access separate OS using my bios "select boot device" option if ubuntu bootloader/grub not installed on the Windows SSD?
  2. If I format my Ubuntu SSD, is it safe to assume that nothing linux/ubuntu/grub/bootloader will be left behind My computer?

Thank you.

condenser
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  • All of grub code is installed in the partition /boot/grub that you dictate, only the MBR (grub stage 0) which is outside of partitions (by definition it's the first 512 bytes of a drive which is reserved for that purpose) is outside of that. When you format a partition/disk you're not talking about the MBR or first 512 bytes (it's outside of data range). You can easily re-write a new MBR over an unwanted MBR though (windows, ubuntu & most OSes have a command for that). Your first point is firmware dependent; yes on many boxes (likely most). – guiverc May 23 '21 at 06:17
  • The Something Else install option and choice of where to install grub boot loader only works with BIOS installs. Systems since 2012 are now UEFI (vendor may say BIOS) and how you boot Ubuntu live installer UEFI or BIOS, is then how it installs. https://help.ubuntu.com/community/UEFI https://askubuntu.com/questions/1296065/dual-booting-w10-ubuntu-with-2-separate-ssds-in-uefi-mode/1296153#1296153 or Remove esp flag from Windows - Tim Richardson https://askubuntu.com/questions/16988/how-do-i-install-ubuntu-to-a-usb-key-without-using-startup-disk-creator/1056079#1056079 – oldfred May 23 '21 at 14:59

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Q1 — Can I access separate OS using my BIOS "select boot device"

Yes, you can certainly do this if you would prefer. In the event you do choose this route, do yourself a favour and disconnect the three other drives beforehand to ensure a more complete isolation of the boot loader.

Q2 — If I [later] format my Ubuntu SSD, is it safe to assume that nothing linux/ubuntu/grub/bootloader will be left behind [my] computer?

Given that Windows really doesn’t like file systems that aren’t NTFS or FAT-based, you would be deleting the partitions and formatting them as something other than a Linux type so, yes, everything Linux-related would be eliminated.

Note that there is no guarantees of “complete isolation” if you’re using Ubuntu (or any other Linux distribution) to modify files, partitions, or metadata on any of the other three partitions. You will need to be conscious of the commands you give the computer if you truly seek isolation.

Alternatively, set Ubuntu up in a virtual machine and save yourself the complexities that arise with a multi-boot system.

matigo
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  • I installed using this method and it works! In case of reinstalling ubuntu for whatever reason, Don't forget to unplug your other hard drives again. I had to do this twice – condenser May 23 '21 at 20:22