DRDO2009: Operating System - Resource Allocation

Question

which of the following is true?

a:resource preemption is allowed in deadlock can be avoided but cannot be prevented

B: if the number of shared resources is greater than the number of process then deadlock can be prevented

C: deadlock can be prevented by not allowing any process to request for resources when it enters the critical section

D: deadlock avoidance schemes required information concerning which resource a process will request and used during its lifetime

Comments

Option D is true

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why not B AND C ?can you plz elaborate

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OPTION B:-

deadlock depend upon not only no.of resources available, it's also depend upon how many resources required by the each processes

let consider P1,P2 and there are R1,R2,R3

P1 requires R1, R3 and P2 requires R1,R2 and R3

now at starting P1 allocates to R3 and P2 allocates R1 ===> lead to deadlock

 

Option C:-

deadlock can be prevented by not allowing any process to request for resources when it enters the critical section

assume when process in CS, you didn't allow any request, after sometime it's coming out of CS,

Now you may allocate and that allocation may leads to DEADLOCK

ex:- interested variable synchronizing method of two processes

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@shaik masthan can u please explain option d

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deadlock avoidance schemes required information concerning which resource a process will request and used during its lifetime

it means, deadlock avoidance scheme ( Bankers Algorithm ) need a prior knowledge about a process requests during it's life time ===> you have to know maximum demand of each process before starting the process to run

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option (d) is correct answer

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can anyone please explain why option (a) is incorrect??

Answer 1

Answer is D ..