Well given my 78 year old Aunt has been running linux for about a year (low requirements), I'd say just do it, if nothing truly holds you to W10.
It's not that hard to partition for two OS's.
1) EFI (assuming you use EFI and not legacy)
2) C:\ for windows 10
3) Linux
4) Shared data repository.

Size as you find needed. That should do you. Utilize swapfile vs swap partition.

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    • Post #14

    Emperor The solution is to use GPT which supports more than four partitions.

        dbarron [deleted] algent Well let's start from the begining-As I see it's better to put Linux on the other HDD, not on the same as W10-if I do that it's type is GPT-do I have to somehow change it to Primary or not? Also when there are two separate HDDs,both having OS how many bootloaders(EFI) I need and where? I want to be able to simply select W10 or Solus when I turn the PC on.
        The other option is HDD with W10-the small primary partition is for system recovery and backup...if I delete it and nothing bad happens and I turn the partition for pictures and so on into logical and that don't delete the files or make something bad to the system, then I will have 2 partitions to make them primary partitions.
        Which one to choose and how to do it safely?
        P.S it would be great to be able to simply copy or backup the OS and put it ready for use on another PC or laptop.
        I also wanna be able to totally erase W10 in the future without compromising the system.

                I use an old PC with BIOS, and about UEFI i don't have any experience.
                If you use two HDD, one with Windows OS and the other with Linux, then if Windows HDD is selected to be booted first you will not see the Linux Option.
                If you select the second HDD to be first on system boot with grub installed on it you will se both systems Windows and Linux but with the Linux as first option. If you want to change the boot order later, as I know that this can be done with Grub Customiser but i don't know how it works on Solus.
                Hope i have explained it well.
                The second options is what i have done, in my PC.

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                  • Post #17

                  Emperor You need only one EFI partition, big enough to have both Solus and Windows bootloaders there.

                  I think there's an issue though since your Windows is installed already in legacy mode, from what I can understand from your post.

                      [deleted] I don't know...I was with W7 and used the free automated update to W10. When trying to install Solus from what I can see it's using EFI(because it's not showing plain text, but more polished-as described in Solus help center it shoud be for EFI) and not BIOS...I am with i5 4460, thus with relatively new motherboad and system.
                      algent So if I go for the secound HDD, there is no problem that it's GPT? Also is grub preinstalled on Solus-thus meaning I would need to install two bootloaders-1 for W10 and another for Solus? And by simply choosing to boot the secound HDD from BIOS I will automatically have a choice to boot W10 or Solus?
                      If so I am gonna do that.
                      Also interested why operating systems have some problems with primary drives and if you install where there are no primary drives?

                            Emperor And by simply choosing to boot the secound HDD from BIOS I will automatically have a choice to boot W10 or Solus?

                            • Yes. Because Grub detect automatically it. Windows by other hand don't do that and don't care if you have installed Linux.

                            Be careful during installatin where you choose to install grub bootloader, because you have to select the Linux HDD.

                                algent Well let the games begin 🙂
                                I will keep in touch to post about eventual problems.

                                  algent Oh I forgot...while installing Windows there was a problem with the motherboard-when you install the drivers for usb 3.0 the system would crash and not boot...do you think the same problem will occur when installing Solus and how can I stop it from installing that driver?
                                  Because if it crash I honestly don't know how I will manage it 🙂
                                  The secound professional that tried to install me that driver ended up saving the system via back up...but now we are talking Linux xD

                                      Emperor I don't think so. I also use a USB 3.0 type. If you can enter in Live Environment then you can install without any problem.

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                                          • Post #24
                                          • Edited

                                          Emperor No, the drivers are a completely different deal in Windows than Linux

                                          algent On EFI you don't install GRUB though

                                                If you have 2 harddisk, I think it's better if you unplug the harddisk with Windows 10 before installing Solus.

                                                algent [deleted] Well that happened before but let's try to solve it:

                                                Basically I returned the empty space from HDD 1 to where it was before.
                                                On the HDD 2 I created an empty space for the installation.
                                                But when I opened GParted it couldn't recognize the partition or the HDD 2...

                                                    On the top right corner there is /dev/sda (1.82TiB) That is HDD1
                                                    If you click there is any /dev/sdb option? (HDD2)

                                                      algent This is HDD 2-the 2TB. The HDD 1 with W10 is 1TB...the HDD 1 is sdb.
                                                      And there is also the USB live boot.
                                                      P.S when I go into BIOS and change the 1-st bootalbe thing to be the USB the 1 TB HDD go to the bottom(3rd place) while 2TB HDD is 2nd place. Is changing the boot order going to help?

                                                        I am not sure, this is new to me.
                                                        Are you going to format it entirely? Find the option "Create a new partition table", and then create partitions as you want.

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                                                          • Post #30

                                                          You sure you've booted Solus in EFI mode?

                                                            [deleted] algent Is there I way to upload a video here or somewhere else and add a link to it?
                                                            P.S I think I found the way.

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                                                                • Post #34

                                                                Try shutting the Windows down completely. Hold SHIFT key while powering off (not rebooting) and see if the partitions still look the same in Gparted.