NPTEL Cloud Computing and Distributed Systems Week 5 Assignment Answers 2025
1. Consider the given table of agreement problems and match the correct pair:
- (P): (i), (Q): (ii), (R): (iii)
- (P): (iii), (Q): (ii), (R): (i)
- (P): (iii), (Q): (i), (R): (ii)
- (P): (ii), (Q): (iii), (R): (i)
Answer :- For Answers Click Here
2. True or False ?
- True
- False
Answer :-
3. True or False ?
“Byzantine agreement cannot be reached among three processors if one processor is faulty”
- True
- False
Answer :-
4. Consider the following statements:
Statement 1: In the synchronous system model, consensus is impossible to solve.
Statement 2: In the asynchronous system model, consensus is solvable.
Statement 3: Paxos provides safety and eventual liveness.
- Only statement 1 is true
- Only statement 1 and statement 2 are true
- Only statement 2 and statement 3 are true
- Only statement 3 is true
Answer :-
5. Find out the correct model for the given assumptions of a system:
Assumption 1: Each message is received within bounded time.
Assumption 2: Drift of each process’ local clock has a known bound.
Assumption 3: Each step in a process takes lb < time < ub , where lb represents lower bound and ub represents an upper bound.
- Asynchronous distributed system
- Synchronous distributed system
- On demand computing system
- Parallel processing system
Answer :-
6. True or False ?
“Koo-Toueg algorithm is a uncoordinated checkpointing and recovery technique that takes a consistent set of checkpointing and avoids domino effect and livelock problems during the recovery”
- True
- False
Answer :- For Answers Click Here
7. Messages whose ‘send’ is done but ‘receive’ is undone due to rollback are called____________.
- In-transit message
- Lost messages
- Orphan messages
- Duplicate messages
Answer :-
8. Cascaded rollback which causes the system to roll back to too far in the computation (even to the beginning), in spite of all the checkpoints is known as_______________________.
- Rollback
- Phantom Effect
- Domino Effect
- Livelock problem
Answer :-
9. Messages with ‘receive’ recorded but message ‘send’ not recorded and do not arise if processes roll back to a consistent global state are called_________________________.
- In-transit message
- Lost messages
- Orphan messages
- Duplicate messages
Answer :-
10. The ____________________may arise when a process rolls back to its checkpoint after a failure and requests all the other affected processes also to roll back.
- Rollback
- Phantom Effect
- Domino Effect
- Livelock problem
Answer :- For Answers Click Here