Chapter 12, Problem 6PE

Explanation of Solution

a.

Redundant Array of Independent Disks (RAID) level 1 scheme:

RAID’s are a number of hard disks which store exact same data. Different RAID levels are available from 1 to 10, each with different significance.

The scheme for getting the effect of atomic block writes with the RAID level 1 (mirroring) is shown below:

• A block write operation is performed as follows, to secure atomicity.
  • Write the information onto the physical block which is located first.
  • Write the similar information onto the physical block located at the second, when the first write accomplishes successfully.
  • Only after the second write accomplishes successfully, the output is announced.
• Each set of “2” physical blocks is tested during recovery.
• Further process is not required if both are same and there is unnoticeable partial-write...

Explanation of Solution

b.

Redundant Array of Independent Disks (RAID) level 5 scheme:

RAID’s are a number of hard disks which store exact same data. Different RAID levels are available from 1 to 10, each with different significance.

The scheme for getting the effect of atomic block writes with the RAID level 5 (block interleaved, distributed parity) is shown below:

• Initially, the data is written in the information block.
• Once this write is successful, the same data is written into the related parity block.
• The write is considered successful only when both the writes are successfully completed...