RAID was first proposed by David A$.$ Patterson et al$.[1]$ They discussed MTTF $($mean time to failure$)*$ when comparing RAID variations. Please calculate the MTTF of RAID $0,$ RAID $1,$ RAID $1+0,$ RAID $5$ and RAID $6$ on the following assumption.

$-$ MTTF of one disk is $1,500,000$ hours $($hrs$)($It is a typical MTTF of hard disks$)$

$-$ MTTR $($mean time to repair$)$ for any RAID is $1$ hour $($In reality, it is not $1$ hour; however, in this quiz we assume MTTR is $1$ hour$)$

$-$ Assuming we have $4$ disks, $10$ disks, and $20$ disks for each RAID $0,1,1+0,5,$ and $6.$

$*$ MTTF is also known as MTBF $($mean time between failure$)$

Don't use AI$!$