Basics of Operating Systems UGC

Question 1

A computer has six tape drives with n processes competing for them. Each process may need two drives. What is the maximum value of n for the system to be deadlock-free?

• 5
• 4
• 3
• 6

Question 2

Consider a disk system with 100 cylinders. The requests to access the cylinders occur in the following sequence: 4,34,10,7,19,73,2,15,6,20 Assuming that the head is current at cylinder 50, what is the time taken to satisfy all requests if it takes 1ms to move from the cylinder to adjacent one and the shortest seek time first policy is used?

• 375ms
• 238ms
• 276ms
• 119ms