Part 3: Information technology managers use RAID arrays to guard against loss of data in case of physical disk failure. Modern disk drives now have sizes in terabytes. What effect does this have on the reliability of RAID arrays? (Hint: What happens when a disk fails? How are data from the failed disk recovered, and how long does that take?)

Part 4: Breaking messages to be sent over a communication facility into packets introduces overhead, a disadvantage. Name and briefly describe three advantages of packet-switched communications.

Part 5: Explain what the ARP protocol does and how it works. (You need about a paragraph of detail; a single sentence will not do.)

In a separate paragraph, tell why the ARP protocol is needed; that is, why is the information provided by ARP even needed at all.