Just a footnote to my above statements.
When I built this computer in Feb. 2015, I didn't have any experience at all with computers. I was watching the news and I saw a report about Windows 10, so I thought that it would be a good time to get rid of my old computer and get a new one. I was just going to buy a new computer, but then I had a wild hair to build my own. Originally this computer had Windows 8, which I immediately upgraded to Windows 8.1 and I began exploring options for Windows 10. I originally just installed Windows 10 and that was it, I played with that for awhile until I figured that I still had a good license for Windows 8.1.
When I originally decided to dual boot, I didn't know how to go about it, but I had an ISO for Windows 10 and an installation disc for Windows 8, so in my mind I figured that the easiest way was on two separate drives. That was a long time ago, when I had absolutely no experience at all with computers. I set my two Windows systems up in separate drives and I used my BIOS to switch back and forth between the different operating systems. That is before I heard of Windows boot managers and stuff like that.
That was fun for a few months until I lost interest in Windows 8.1, and then I switched one of my drives over to Linux Mint 17.2 Cinnamon, and added the grub boot manager, that was much easier than using my BIOS menu to switch back and forth between different operating systems. I have had my pitfalls, I have lost a few operating systems here and there and a few boot partitions, but in the end it was just a self-guided adventure. I am at the point now where at any time I can change any one OS out without physically disconnecting any drives. Recently I switched out my 3rd hard drive from openSUSE 42 to Ubuntu without any effect at all on the other two operating systems. I can also change my Windows 10 whenever I want without effecting my Linux installs. For example I recently upgraded my Windows 10 from the Threshold build to the Redstone build. If I get tired of the Redstone build, I can go right back to the Threshold build without effecting the other two drives.
I have my Ubuntu on an approx. 300 GB partition of a 1 terabyte hard drive because I use the 700 gb partition as my main storage for all 3 operating systems. That was a real trick to figure out and implement, but it works like a charm. I use my two desktop drives simply as mirrored back ups for all of my data. Again, this was all self-guided, I could not find documentation online to guide me to where I envisioned this computer to be. I can also access my 2 desktop drives from any operating system, that was fun to figure out.
It is my computer. I built it for fun and I am having fun.