RAID controller?

Can someone tell me, when using RAID (mirrored);

  1. How is the RAID managed? Is there a hardware controller or is it software on the drive(s)?

  2. What happens if the controller fails? Is the data stored on the drives in such a way that it would be readable without the RAID controller / My Book? Having a mirrored unit is only safe as long as you are not dependant on the controller hardware or software not failing (had this happen to me before).

It’s software-based.