Applied Test Series

Question

There are 5 processes in a system where each of them has a requirement of x resources. In the worst case, y number of resources would ensure that the system is deadlock free.

The system later on has 7 processes that require x resources each. In the worst case, (y + 4) resources would ensure that the system is deadlock free.

The value of x is ______

Answer 1

x = 3

The condition for the system to ensure it is deadlock free is given as -

$\sum$ Si = m + n -1

(where Si = sum of resources required by all the processes, m = number of resources available, n= number of processes)

Now according to question,

5 * x = y + 5 -1

5x = y + 4        ------ (1)

7 * x = (y + 4) + 7 – 1     

7x = y + 10      ------- (2)

By subtracting eqn (1) from (2) we get ;

x = 3

Comments

The formula is Correct.

The condition for the system to ensure it is deadlock free is given as -

$∑ Si = m + n$  ${\color{Green}- }$ $1$

ref: https://gateoverflow.in/1394/gate-cse-2005-question-71

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The condition is correct.

ref :

https://www.geeksforgeeks.org/program-for-deadlock-free-condition-in-operating-system/#:~:text=Given%3A%20A%20system%20has%20R,that%20deadlock%20will%20never%20occur.

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Yes, you are correct.

My mistake :(