?For the systems described in Questions 13 through 16 below, given that all of t

ID: 643940 • Letter: #

Question

?For the systems described in Questions 13 through 16 below, given that all of the devices are of the same type, and using the definitions presented in the discussion of the Bankers Algorithm, answer these questions: a. Calculate the number of available devices. b. Determine the remaining needs for each job in each system. c. Determine whether each system is safe or unsafe. d. If the system is in a safe state, list the sequence of requests and releases that will make it possible for all processes to run to completion. e. If the system is in an unsafe state, show how its possible for deadlock to occur. 13. This system has 16 devices.

?For the systems described in Questions 13 through 16 below, given that all of the devices are of the same type, and using the definitions presented in the discussion of the Banker½s Algorithm, answer these questions: a. Calculate the number of available devices. b. Determine the remaining needs for each job in each system. c. Determine whether each system is safe or unsafe. d. If the system is in a safe state, list the sequence of requests and releases that will make it possible for all processes to run to completion. e. If the system is in an unsafe state, show how it½s possible for deadlock to occur. 13. This system has 16 devices.

Explanation / Answer

Total devices = 16

Devices allocated = 5 + 3 + 4 + 2 = 14

Available devices = 16 – 14 = 2

Remaining = Maximum Required – Devices Allocated

Job No.

Devices Allocated

Maximum Required

Remaining Needs

Job 1

8 – 3 = 5

Job 2

9 – 3 = 6

Job 3

8 – 4 = 4

Job 4

5 – 2 = 3

The system is in unsafe state because the available devices do not satisfy the need of any job.

Suppose the available devices are allocated to the jobs, the available devices become zero.

Now all the jobs are waiting for the additional devices to complete their task. But no devices are available to allocate.

The jobs are in waiting state forever.

This indicates that the system is in dead lock.