Consider the following table as a snapshot of resources in a system: A (10 instances), B (5 instances), and C (7 instances). a) Write down the calculation steps to find a Safe/Unsafe state: b) Is this system in a safe state? If so, write the safe sequence.

Consider the following table as a snapshot of resources in a system: A (10 instances), B (5 instances), and C (7 instances). a) Write down the calculation steps to find a Safe/Unsafe state: b) Is this system in a safe state? If so, write the safe sequence.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Solve the following bankers Algorithm and find a save sequence 5 processes P0 P1 P2 P3 P4; 3 resource types A (20 instances), B (10 instances), and C (14 instances). Snapshot at time T0: Allocation Max Available A B C A B C A B C P0 0 2 0 14 10 3 6 6 4 P1 4 0 0 6 4 4 P2 6 0 4 18 0 4 P3 4 2 2 4 4 4 P4 0 0 4 8 6 6
Hey, I have already received a good answer to this question but I am looking for greater detail to be provided. There are three processes P1, P2 and P3 are running in a system with 3 instances of a resource R1, 2 instances of a resource R2, and 2 instances of a resource R3. At a given time the allocation matrix is: A = [{1, 1, 1} { 0, 1, 0} { 1, 0, 0 }] Assume that the maximum matrix is M = [ {2,2,1} {1,1,1} {3,1,0}] While in this state, a new process P4 is created which requires at most 2 instances of R1 and one instance of R2. This process initially requests one instance of R1 to be allocated to it. Using the Banker’s algorithm, determine whether this request can be granted or must be refused.
b.Start from the resource allocation state in Q 13. If a request from a process P3 arrives for (1, 2, 3), can the request be immediately granted ? Why or why not ? c.Start from the resource allocation state in Q 13. Suppose that P4 asks for 2 instances of resource B. Can the system grant this if it wants to avoid deadlock ? Explain.
Suppose a system has 5 processes, P = {P1, P2, P3, P4, P5}, and 4 resources, R = {R1, R2, R3, R4}, where there are 2 instances of R1, 1 instance of R2, 3 instances of R3, and 3 instances of R4. The current state of the system is defined by the following requests and assignments: P1 is requesting an instance of R3 and has been assigned an instance of R2; P2 is requesting an instance of R1 and has been assigned an instance of R3; P3 is requesting an instance of R4 and has been assigned an instance of R1 and an instance of R3; P4 is requesting an instance of R3; P5 is requesting an instance of R2 and has been assigned an instance of R4. Is there deadlock in this system? (Explicitly state yes, there’s deadlock or no, there isn’t.) If applicable, draw a wait-for graph or resource-allocation graph, and use the appropriate graph to justify your answer. If you conclude there is no deadlock, your justification should contain a sequence of execution for the processes which shows that…
Consider the following resource-allocation policy. Requests for and releases of resources are allowed at any time. If a request for resources cannot be satisfied because the resources are not available, then we check any processes that are blocked waiting for resources. If a blocked process has the desired resources, then these resources are taken away from it and are given to the requesting process. The vector of resources for which the blocked process is waiting is increased to include the resources that were taken away. For example, consider a system with three resource types and the vector Available initialized to (4, 2, 2). If process P0 asks for (2, 2, 1), it gets them. If P1 asks for (1, 0, 1), it gets them. Then, if P0 asks for (0, 0, 1), it is blocked (resource not available). If P2 now asks for (2, 0, 0), it gets the available one (1, 0, 0) and one that was allocated to P0 (since P0 is blocked). P0’s Allocation vector goes down to (1, 2, 1), and its Need vector goes up to (1,…
(i) What is the content of the matrix Need? Is the system in a safe state? If yes, indicate the possible safe sequence. (ii) If a request from process P1 arrives for resource types (A, B, C) , and the number of instances 4, 2, 0 respectively, can the P1 request resources be granted immediately?Explain.
Please explain step by step how processes are created. 1. Including the parent process, how many processes are created by the following program? Assumethat all fork() system calls succeed. #include <unistd.h>#include <stdio.h>int main(int argc, char **argv) {for (int i = 0; i < 3; i++)fork();/* ... */}2. Given the following program, please determine how many times the word “hello” is printed out.Assume that fork() is always successful. #include <sys/types.h>#include <stdio.h>int main() {pid_t a, b;a = fork();b = fork();if (a == 0)b = fork();if (b == 0)a = fork();printf(“hello\n”);return 0;} 2. Given the following program, please determine how many times the word “hello” is printed out.Assume that fork() is always successful. [1 pt]#include <sys/types.h>#include <stdio.h>int main() {pid_t a, b;a = fork();b = fork();if (a == 0)b = fork();if (b == 0)a = fork();printf(“hello\n”);return 0;}
When a deadlock has been identified, the requested resources are made available to those who are unable to go forward.
Point out a deadlock problem and make minor revision to avoid the deadlock: int a[10], b[10], myrank; MPI_Status status; ... MPI_Comm_rank(MPI_COMM_WORLD, &myrank); if (myrank == 0) { MPI_Send(a, 10, MPI_INT, 1, 1, MPI_COMM_WORLD); MPI_Send(b, 10, MPI_INT, 1, 2, MPI_COMM_WORLD); } else if (myrank == 1) { MPI_Recv(b, 10, MPI_INT, 0, 2, &status, MPI_COMM_WORLD); MPI_Recv(a, 10, MPI_INT, 0, 1, &status, MPI_COMM_WORLD); } ...
Using a resource allocation graph, show the possibility of a deadlock in this implementation. Modify the order of some of the get requests to prevent the possibility of any deadlock. Is it possible that a resource deadlock involves multiple units of one type and a single unit of another? If so, give an example.
Consider the following snapshot of a system: Allocation: A B C DT0 0 0 1 2T1 1 0 0 0T2 1 3 5 4T3 0 6 3 2T4 0 0 1 4 Max: A B C DT0 3 0 1 2T1 1 7 5 0T2 2 3 5 6T3 0 6 5 3T4 0 6 5 6 Available: A B C D2 5 1 0 Answer using the banker’s algorithm. If you think the system is in an unsafe state, write "unsafe" in the answer box, otherwise, write the process sequence that satisfies the safe state. While answering the question write only the id of the Tasks separated with comma, (e.g., for sequence <T4,T2,T1,T0,T3> write only 4,2,1,0,3 ).
P is a set of processes. R is a set of resources. E is a set of request or assignment edges. The sets P, R, and E are as follows: P = {P1, P2, P3} R = {R1, R2, R3} E = {P1 -> R1, P2 -> R3, P3-> R2, R1 -> P2, R2 -> P2, R2 -> P1, R3 -> P3} R1 has one instance. R2 has two instances. R3 has one instance. a. Explain clearly with the help of a properly labelled diagram what is a resource allocation graph? Draw the resource-allocation graph for the given case also. b. Is there any deadlock in this situation? Explain your answer clearly.