A disk system is to be constructed using some number of identical disk drives each of which can store up to T terabytes of data.

3.  A disk system is to be constructed using some number of identical disk drives each of which can store up to T terabytes of data.  A large database of size 4×T terabytes is to be stored on the disk system. What is the minimum total number of  disks that would be required for the system if the disk system is a:

RAID4 system?

RAID5 system?

RAID6 system?

RAID1 system?

RAID0 system?