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A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?
- a)-2
- b)-1
- c)1
- d)2
Correct answer is option 'D'. Can you explain this answer?
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Verified Answer
A shared variable x, initialized to zero, is operated on by four concu...
Processes can run in many ways, below is one of the cases in which x attains max value
Semaphore S is initialized to 2 Process W executes S=1, x=1 but it doesn't update the x variable.
Then process Y executes S=0, it decrements x, now x= -2 and signal semaphore S=1
Now process Z executes s=0, x=-4, signal semaphore S=1
Now process W updates x=1, S=2 Then process X executes X=2
Semaphore S is initialized to 2 Process W executes S=1, x=1 but it doesn't update the x variable.
Then process Y executes S=0, it decrements x, now x= -2 and signal semaphore S=1
Now process Z executes s=0, x=-4, signal semaphore S=1
Now process W updates x=1, S=2 Then process X executes X=2
So correct option is D
Most Upvoted Answer
A shared variable x, initialized to zero, is operated on by four concu...
Analysis:
To find the maximum possible value of x after all processes complete execution, let's consider the actions of each process and analyze the effects on x.
Process W:
1. Reads x from memory (x = 0)
2. Increments x by one (x = 1)
3. Stores x to memory
4. Terminates
Process X:
1. Reads x from memory (x = 0)
2. Increments x by one (x = 1)
3. Stores x to memory
4. Terminates
Process Y:
1. Waits on semaphore S (decrements S by one)
2. Reads x from memory (x = 1)
3. Decrements x by two (x = -1)
4. Stores x to memory
5. Signals semaphore S (increments S by one)
6. Terminates
Process Z:
1. Waits on semaphore S (decrements S by one)
2. Reads x from memory (x = 1)
3. Decrements x by two (x = -1)
4. Stores x to memory
5. Signals semaphore S (increments S by one)
6. Terminates
Analysis of the order of execution:
1. Processes W and X can execute concurrently since they don't depend on each other.
2. Process Y waits on semaphore S, so it will execute after either W or X completes.
3. Process Z waits on semaphore S, so it will execute after either W or X completes, but it will not execute concurrently with Y since the semaphore S will be decremented to 0 by Y.
Execution scenario:
1. Process W executes and increments x to 1.
2. Process Y executes since W completed and decrements x to -1.
3. Process Z executes since Y completed and decrements x to -2.
4. Process X executes since Z completed and increments x to -1.
Conclusion:
The maximum possible value of x after all processes complete execution is -1. Therefore, option (b) is the correct answer.
To find the maximum possible value of x after all processes complete execution, let's consider the actions of each process and analyze the effects on x.
Process W:
1. Reads x from memory (x = 0)
2. Increments x by one (x = 1)
3. Stores x to memory
4. Terminates
Process X:
1. Reads x from memory (x = 0)
2. Increments x by one (x = 1)
3. Stores x to memory
4. Terminates
Process Y:
1. Waits on semaphore S (decrements S by one)
2. Reads x from memory (x = 1)
3. Decrements x by two (x = -1)
4. Stores x to memory
5. Signals semaphore S (increments S by one)
6. Terminates
Process Z:
1. Waits on semaphore S (decrements S by one)
2. Reads x from memory (x = 1)
3. Decrements x by two (x = -1)
4. Stores x to memory
5. Signals semaphore S (increments S by one)
6. Terminates
Analysis of the order of execution:
1. Processes W and X can execute concurrently since they don't depend on each other.
2. Process Y waits on semaphore S, so it will execute after either W or X completes.
3. Process Z waits on semaphore S, so it will execute after either W or X completes, but it will not execute concurrently with Y since the semaphore S will be decremented to 0 by Y.
Execution scenario:
1. Process W executes and increments x to 1.
2. Process Y executes since W completed and decrements x to -1.
3. Process Z executes since Y completed and decrements x to -2.
4. Process X executes since Z completed and increments x to -1.
Conclusion:
The maximum possible value of x after all processes complete execution is -1. Therefore, option (b) is the correct answer.
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A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer?
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A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? for Computer Science Engineering (CSE) 2024 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer?.
A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? for Computer Science Engineering (CSE) 2024 is part of Computer Science Engineering (CSE) preparation. The Question and answers have been prepared according to the Computer Science Engineering (CSE) exam syllabus. Information about A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Computer Science Engineering (CSE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer?.
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A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer?, a detailed solution for A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice A shared variable x, initialized to zero, is operated on by four concurrent processes W, X, Y, Z as follows. Each of the processes W and X reads x from memory, increments by one, stores it to memory, and then terminates. Each of the processes Y and Z reads x from memory, decrements by two, stores it to memory, and then terminates. Each process before reading x invokes the P operation (i.e., wait) on a counting semaphore S and invokes the V operation (i.e., signal) on the semaphore S after storing x to memory. Semaphore S is initialized to two. What is the maximum possible value of x after all processes complete execution?a)-2b)-1c)1d)2Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice Computer Science Engineering (CSE) tests.
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