Madeeasy_SubjectTest_OperatingSystem

Question

Comments

answer is right.... try one more time.... note that the three function calls are in parallel execution

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yeah I got it ..thank you

Answer 1

The maximum value of $count = 45$ & the minimum value of the $count = 6$. So C. $45, 6$ is the corect answer.

In the CPU, count = count + 3 will be perform the below operations -

LOAD count // AC <- count
INCREMENT 3 // AC <- AC + 3
STORE count // count <- AC

Note that, count & n is global variable in the given code.

To find the maximum value of count, we have to run GATE-1(), GATE-2() & GATE-3() in sequential manner. And we get the maximum value of $count = 45$.

To find the minimum value of count, we have follow the below steps -

So, the minimum value of count is $6$.

Comments

Don't waste your time for answering question which have already sufficient answers/comments for the solution.

You need to spend it wisely especially in December and January.

Answer 2

I am able to get the point that how it is 45 because suppose a process came and it does not got preempt so he will execute all gate() function and now all the one execution of gate() leads to value 15 therefore 3 execution will lead to 45.

Now coming for min value i am just not able to get according to me it should be zero.

Comments

U know how 6 came then pls explain the concept

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Note that the three calls runs concurrently, i will denote them as

Gate1(), Gate2(), Gate3()

start the for loop at same time in all three functions, note that count is global and i is local

 

1.Load count

2.Increment count by 3

3.Store in count

 

load the count=0 in each function

now run GATE1() fully ===> count = 15

but noe that GATE2() and GATE3() already load count=0

now GATE2(), run for loop run i=1,2,3,4 ===> GATE2() makes the value count=12

now GATE3(), run for loop run i=1 ===> GATE3() makes the value count=3

now GATE2(), run for loop run i=5 ===> GATE2() makes the value count=6 but stop at before storing ( i mean preempt at 3rd instruction in low level )

now GATE3(), run for loop run i=2,3,4,5 ===> GATE3() makes the value count=15

now preempt GATE2(), it will store 6 in count....

All three functions executed....

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@Shaik Masthan

VERY NICE EXPLANATION BRO

HOW AM I EVER GOING TO THINK LIKE THIS :(