Consider the following snapshot of the system.
Process |
Allocation |
Max |
Available |
||||||
A |
B |
D |
A |
B |
C |
A |
B |
C |
|
P1 |
0 |
1 |
0 |
7 |
5 |
3 |
3 |
3 |
2 |
P2 |
2 |
0 |
0 |
3 |
2 |
2 |
|||
P3 |
3 |
0 |
2 |
9 |
0 |
2 |
|||
P4 |
2 |
1 |
1 |
2 |
2 |
2 |
|||
P5 |
0 |
0 |
2 |
4 |
3 |
3 |
|||
Answer the following
-
What is the content of the need matrix?
-
Is the system in a safe state?
-
If the request for process P2 arrives for (1, 0, 2) can it be granted immediately.
Consider the following snapshot of the system.
Process |
Allocation |
Max |
Available |
||||||
A |
B |
C |
A |
B |
C |
A |
B |
C |
|
P0 |
0 |
0 |
2 |
0 |
0 |
4 |
1 |
0 |
2 |
P1 |
1 |
0 |
0 |
2 |
0 |
1 |
|||
P2 |
1 |
3 |
5 |
1 |
3 |
7 |
|||
P3 |
6 |
3 |
2 |
8 |
4 |
2 |
|||
P4 |
1 |
4 |
3 |
1 |
5 |
7 |
|||
Answer the following
-
What is the content of the need matrix?
-
Is the system in a safe state?
-
If the request for process P2 arrives for (0, 0, 2) can it be granted immediately.
Consider the following snapshot of the system.
Process |
Allocation |
Max |
Available |
|||||||||
A |
B |
C |
D |
A |
B |
C |
D |
A |
B |
C |
D |
|
P1 |
0 |
0 |
1 |
2 |
0 |
0 |
1 |
2 |
1 |
5 |
2 |
0 |
P2 |
1 |
0 |
0 |
0 |
1 |
7 |
5 |
0 |
||||
P3 |
1 |
3 |
5 |
4 |
2 |
3 |
5 |
6 |
||||
P4 |
0 |
6 |
3 |
2 |
0 |
6 |
5 |
2 |
||||
P5 |
0 |
0 |
1 |
4 |
0 |
6 |
5 |
6 |
||||
Answer the following
-
What is the content of the need matrix?
-
Is the system in a safe state?
-
If the request for process P1 arrives for (0,4,2,0) can it be granted immediately.
Consider the following snapshot of the system.
Process |
Allocation |
Max |
Available |
|||||||||
A |
B |
C |
D |
A |
B |
C |
D |
A |
B |
C |
D |
|
P1 |
4 |
0 |
0 |
1 |
6 |
0 |
1 |
2 |
3 |
2 |
1 |
1 |
P2 |
1 |
1 |
0 |
0 |
1 |
7 |
5 |
0 |
||||
P3 |
1 |
2 |
5 |
4 |
2 |
3 |
5 |
6 |
||||
P4 |
0 |
6 |
3 |
3 |
1 |
6 |
5 |
3 |
||||
P5 |
0 |
2 |
1 |
2 |
1 |
6 |
5 |
6 |
||||
Answer the following
-
What is the content of the need matrix?
-
Is the system in a safe state?
-
If the request for process P4 arrives for (1,2,0,0) can it be granted immediately.
The OS contains 3 resources, the number of instance of each resource type are 7, 7, 10. The current resource allocation state is as shown below.
Process |
Current allocation |
Maximum need |
||||
R1 |
R2 |
R3 |
R1 |
R2 |
R3 |
|
P1 |
2 |
2 |
3 |
3 |
6 |
8 |
P2 |
2 |
0 |
3 |
4 |
3 |
3 |
P3 |
1 |
2 |
4 |
3 |
4 |
4 |
Is the current allocation in a safe state?
Consider the following system snapshot using data structures in the Bankers algorithm, with resources A, B, C and D and process P0 to P4.
Process |
Allocation |
Max |
Available |
|||||||||
A |
B |
C |
D |
A |
B |
C |
D |
A |
B |
C |
D |
|
P0 |
6 |
0 |
1 |
2 |
4 |
0 |
0 |
1 |
3 |
2 |
1 |
1 |
P1 |
1 |
7 |
5 |
0 |
1 |
1 |
0 |
0 |
||||
P2 |
2 |
3 |
5 |
6 |
1 |
2 |
5 |
4 |
||||
P3 |
1 |
6 |
5 |
3 |
0 |
6 |
3 |
3 |
||||
P4 |
1 |
6 |
5 |
6 |
0 |
2 |
1 |
2 |
||||
Using Bankers algorithm answer the following
-
How many resources of Type A, B, C and D are there?
-
What is the content of the need matrix?
-
Is the system in a safe state? Why?
-
If the request for process P4 arrives for additional resources of (1,2,0,0) can it be granted immediately. Show the system state and other criteria
Consider the following snapshot of a system. Execute Bankers algorithm to answer the following
Process |
Allocation |
Max |
Available |
|||||||||
A |
B |
C |
D |
A |
B |
C |
D |
A |
B |
C |
D |
|
P0 |
2 |
0 |
1 |
2 |
2 |
0 |
1 |
2 |
2 |
4 |
2 |
1 |
P1 |
1 |
0 |
0 |
0 |
2 |
7 |
5 |
0 |
||||
P2 |
1 |
3 |
5 |
4 |
2 |
3 |
5 |
6 |
||||
P3 |
0 |
6 |
3 |
2 |
0 |
7 |
5 |
2 |
||||
P4 |
0 |
0 |
1 |
4 |
0 |
7 |
5 |
6 |
||||
-
Is the system in a safe state?
-
If the system is in a safe state, show how all the process could complete their execution successfully. If the system is unsafe, show how deadlock might occur. Explain.
-
If the request for process P1 arrives (1, 4, 2, 0) can the request be granted immediately?
Consider the following snapshot of the system.
Process |
Allocation |
Max |
Available |
||||||
A |
B |
D |
A |
B |
C |
A |
B |
C |
|
P1 |
0 |
1 |
0 |
7 |
5 |
3 |
3 |
3 |
2 |
P2 |
2 |
0 |
0 |
3 |
2 |
2 |
|||
P3 |
3 |
0 |
2 |
9 |
0 |
2 |
|||
P4 |
2 |
1 |
1 |
2 |
2 |
2 |
|||
P5 |
0 |
0 |
2 |
4 |
3 |
3 |
|||
Answer the following
-
What is the content of the need matrix?
-
Is the system in a safe state?
-
If the request for process P2 arrives for (0, 2, 0) can it be granted immediately.
Consider the following snapshot of the system. Execute Bankers algorithm to answer the following.
Process |
Allocation |
Max |
Available |
||||||
A |
B |
D |
A |
B |
C |
A |
B |
C |
|
P0 |
0 |
0 |
1 |
0 |
0 |
1 |
1 |
5 |
2 |
P1 |
1 |
0 |
0 |
1 |
7 |
5 |
|||
P2 |
1 |
3 |
5 |
2 |
3 |
5 |
|||
P3 |
0 |
6 |
3 |
1 |
6 |
5 |
|||
P4 |
0 |
0 |
1 |
5 |
6 |
5 |
|||
Answer the following
-
What is the content of the need matrix?
-
Is the system in a safe state?
-
If the system is in a safe state, show how all the process could complete their execution successfully. If the system is unsafe, show how deadlock might occur. Explain.
-
If the request for process P1 arrives for (0, 4, 2) can it be granted immediately. If granted write the safe sequence.
Assume a system with four resource types R0, R1, R2 and R3. The number of instances of each resource type is 6, 4, 4 and 2 respectively. The maximum claim and the current allocation are shown in the following table. Is this a safe state? Why or why not?
Process |
Maximum claim |
Allocation |
||||||
R0 |
R1 |
R2 |
R3 |
R0 |
R1 |
R2 |
R3 |
|
P0 |
3 |
2 |
1 |
1 |
2 |
0 |
1 |
1 |
P1 |
1 |
2 |
0 |
2 |
1 |
1 |
0 |
0 |
P2 |
1 |
1 |
2 |
0 |
1 |
1 |
0 |
0 |
P3 |
3 |
2 |
1 |
0 |
1 |
0 |
1 |
0 |
P4 |
2 |
1 |
0 |
1 |
0 |
1 |
0 |
1 |