(a) With 250 disks in the disk array, what is the highest and lowest storage efficiency?

Which RAID architecture offers the best and the worst efficiency?

(b) Consider a system with 5 blocks of data and one parity disk. Let a block read be 1 cycle and block write be 2 cycles. Let logical XOR take 1 cycle. When a block is being written into the system, list the following for RAID3 and RAID4 systems.

(i) What are the operations that will be performed?

RAID3:

RAID4:

(ii) What is the total cycle time for the operation?

RAID3:

RAID4:

(c) What is the main difference between RAID4 and RAID5? What problem does the

RAID5 solve?