Quiz 6

Q1. What is the difference between a physical address and a virtual address?

Q2. Explain the difference between internal fragmentation and external fragmentation. Which one occurs in paging systems? Which one occurs in systems using pure segmentation?

Q3. What is the device independence?

Q4. Disk requests come in to the disk driver for cylinders 10, 22, 20, 2, 40, 6, and 38, in that order. A seek takes 6 msec per cylinder moved. How much seek time is needed for

• First-come, first-served.

• Shortest seek time first.

• Elevator algorithm.

In all cases, the arm is initially at cylinder 20.