Windows 10: Dual boot XP on top of Windows 10

You could swap your Windows 10 drive with your Windows XP drive and then switch on the computer without having to change the boot sequence in BIOS, if you need to use XP. After that, you shutdown, swap to your Windows 10 disk and keep using your PC as normal. The only inconvenience is that you have to turn off the computer to change disks while in the standard dual-boot scenario all you have to do is configure Windows 10 boot loader to also boot Windows XP or leave booting from Windows 10 as default and bypass boot sequence (usually F8 or F9 or F11 depending on motherboard model) if you need to boot from XP instead.

PS: Another convenience of having both disks connected is that you can easily share files between the two operating systems.

 

My Windows 10 is installed on a permanently installed internal SSD. When I want to boot into Windows 7, I just slide the HDD into the dock and use the boot override menu to boot from it. Without using the boot override menu, the computer just boots into Windows 10 whether or not there is a drive in the dock. It's also good for connecting a HDD to save backup images on, much faster than a USB connection.

 

Such drive swapping device is good fo more than that. I have one with 3 bays for 3.5" HDDs, Now looking for at least a double one for 2.5" drives. When I do clean installation of any OS I disconnect all other drives so there's no mixing of boot sectors. It's much easier to take them out than to open case and take cables off. I keep one of 3 bays
empty and just plug in a backup drive as needed. Backups are way faster than even with USB3 connection. Don't even have to turn computer off to swap any non-OS drives.
There are also switch boards for power for individual drives which I also plan to incorporate. All of that will give me very universally configurable machine.

 

I agree with you but the primary reason these drive bays are used is for safety. When you have sensitive data on a disk, you can simply remove it from the computer when not in use (after the day is over) and keep it locked somewhere safe. This is for military and business applications of course. We normal users would simply swap data or OS hard disk easily with these bays.