Maybe the question is stupid, but I haven't been able to find anything anywhere to confirm that.
I have 1TB HDD which has two ext4 partitions. In one partition, I've my main OS (Ubuntu). And another partition is empty.
I'd like to install an another OS in my second partition. Is it possible, while being in one partition (Ubuntu), to install an OS in another unmounted partition ( and finally update the grub menu ).