ISRO CSE 2009 | Question: 77

Question

When a process is rolled back as a result of deadlock the difficulty which arises is

• A. Starvation
• B. System throughput
• C. Low device utilization
• D. Cycle stealing

Comments

please explain me meaning of this line if possible give me a best example for this line 

"  process is rolled back as a result of deadlock "

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In situations where deadlock is a real possibility, the system can periodically make a record of the state of each process and when deadlock occurs, roll everything back to the last checkpoint, and restart, but allocating resources differently so that deadlock does not occur.

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any example ??

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I have never heard about it

Answer 1

We can see the example of bridge crossing, in which bridge has only one lane.

Deadlock will occur when 2 cars of opposing direction meet.

one or more cars may have to backed up if deadlock occurs.

Then starvation(indefinite waiting) is possible.

Comments

why not system throughput. it will also get affected

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Yes, it does. But starvation is a better answer here.

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True, lower throughput sounds like a lesser problem than starvation.

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I think starvation is the only perfect answer here.

Answer 2

I guess starvation should be the answer if we rollback the process there may be possiblity again deadlock occur so it may goes in starvation.

OPTION A

Answer 3

1. Starvation might happen for the process but can be avoided.

2. System throughput will be affected as the whole execution of the process till the rollback is going waste.

3. Device is used in rollback - actually more than the ideal case.

4 Cycle stealing is not a related concept. 

So, answer is 2- System throughput as starvation might not always be there. 

Answer 4

So here also answer should be c . Ryt ?

Comments

nopes. It should be B. Device is used though the usage is wasted.

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When i tried for the first time .i was sure that a ,b are correct . but when you said me overconservative i thought c . I agree with your answer . But they are so closely related to each other :( i find a,b,c are somehere getting affected due to rollback :(

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And sir but of all those 3 System thoughput is most importnat one right ? Because all the computation done so far has to done again . This is the reason why you said B ? Computaion matter more rather than no of process queue for starvation and low device utilization

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yes. but it is not just the better option. And you should read the words in question clearly for GATE- starvation "might" happen. But we can't say starvation "will" happen. But "system throughput" will be affected.

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here https://gateoverflow.in/18583/isro2009-77 

ans is A  so which one is correct 

also system throughput might increase if deadlock is resolved