UGC NET CSE | August 2016 | Part 2 | Question: 38

Question

Consider a system having ‘m’ resources of the same type. These resources are shared by three processes $P_{1} , P_{2}$ and $P_{3}$ which have peak demands of $2, 5$ and $7$ resources respectively. For what value of $'m'$ deadlock will not occur ?

• A. $70$
• B. $14$
• C. $13$
• D. $7$

Answer 1

Peak demands of p1,p2,p3 are 2,5 and 7.

allocate 1 less than peak demand  i.e,, p1 --> 1 ,p2-->4 ,p3-->6

the number of resources for which deadlock occurs is 1+4+6 = 11

Add one to the number of resources we get 12 ,the value for which deadlock will not occur . ( 13 is nearest possible answer )

Answer 2

For deadlock free condition , at least one process will be given full no of resouces and rest of processes will be given 1 less their max demands.

So (2-1) + (5-1) + 7 = 1 + 4  = 12

Hence A,B and C all satisfy the criteria .

So the correct options should be A,B and C

Answer 3

If  m>=12 then It is Deadlock Free

So we say that Option A , B and C all are Right