ISRO2007-40

Question

Consider a system having ‘m’ resources of the same type. The resources are shared by 3 processes A, B, C, which have peak time demands of 3, 4, 6 respectively. The minimum value of ‘m’ that ensures that deadlock will never occur is

• A. 11
• B. 12
• C. 13
• D. 14

Answer 1

If we have m resource's of same type and they are shared by 3 process's then

A needs 3 resource's of same type .

B needs 4 resource's of same type .

C needs 6 resource's of same type .

first of all we find out after how many resource's if we give them the system still be in Deadlock.

So

A needs 3 resource's of same type .If we only give 2 resource to A then it will still be in deadlock

B needs 4 resource's of same type .If we only give 3 resource to B then it will still be in deadlock

C needs 6 resource's of same type .If we only give 5 resource to C then it will still be in deadlock

we have given total of 10 resources still the system is in deadlock .To break this deadlock we give them one more.

So Answer :A (11 resources of same type).

Answer 2

Option A will be right option.

A =2 Unit

B=3 Unit

C=5 unit

Condition for deadlock=10 so condition for not happenning deadlock in system=11