SATA hard drive in slave

[God-like]

Hi,
That happens when I connects two SATA hard disk with two OS?
I am lazy to unplug one of two,then we never know if it's like the idle,then I recognized that it is on the other slave master?
I know that if I plug adapter with a USB> SATA is recognized slave but on the same motherboard, I have never done for now.

[Luther]

The boot disk is chosen in the bios ... therefore, no master, no slave IDE

[God-like]

Hello,

If the 2 harddrive with OS are plugged into the motherboard then the hard drive is not recognized at boot and will be absent or appear as a data disc?

Is I am on a right path?

[Reginald]

If both are plugged one of your discs will be recognized data disc.