operating system disk scheduling

Question

any shortcut method for this??

Comments

I never saw any shortcut method for this. But each question is beautifully framed such that at each stage we need to check few states only.

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i think it will take more than 5 min , and can you please explain

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See @ air1ankit  if option are given then  we can save some time BUT Regarding This numerical type question u have to solve fully and see the process which are safe or in deadlock .

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16

at initial available resources are <3,3,2> so only  P1 and p3 can satisfies

so in first case take P1 and second case take p3  like each step you have to check like TOPOLOGICAL SORTING  is there any way or not

Answer 1

Need=Max- Allocation

P0=(7 4 3)

P1=(1 2  2)

P2=(6 0 0)

P3=(0 1 1)

P4=(4 3 2)

Now check 

Case1: if Need >Available then WAIT

Case2: if Need ≤Available then GRANT

And update Available, Available=Available+ Allocation

P0=Case1

P1= Case2  •°• Available=(5 3 2)

P2= Case1

P3= Case2  •°• Available=(7 4 3)

P4= Case2  •°• Available=(7 4 5)

P2=Case2  •°• Available=(10 4 7)

Now turn is P0

Then safe sequence is P1->P3->P4->P2->P0

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There is no short cut to determine safe sequence or Bankers Algorithm. We have to calculate it.