Consensus?

Question 1

What does the principle of consensus determine?

Answer 1

The power of sync primitives

Question 2

What is the basic idea of Consensus

Answer 2

Each class in hierarchy has an associated consensus number

Question 3

What is a Consensus number?

Answer 3

Max no of threads for which objects can solve consensus

Question 4

What method does a consensus object have?

Answer 4

decide()

Question 5

what does decide() return in consensus object?

Answer 5

a value that is consistent and valid (all threads decide the same value, the common decision value is some thread’s input)

Question 6

Can 2 threads reach consensus on 2 values using atomic registers?

Answer 6

No

Question 7

What consensus number does an atomic number have?

Answer 7

1

Question 8

Can a FIFO Queue Implement Consensus?

Answer 8

Yes, but only for 2 threads (consensus number 2)

Question 9

what is the consensus number of non-trivial RMW objects?

Answer 9

2

Question 10

What methods do subclasses of consensus have?

Answer 10

propose(x)
decide(object value)

Question 11

If a RMW object overwrites/commutes what is the consensus number?

Answer 11

2

Question 12

What is the consensus number of compareAndSet() and get()

Answer 12

Infinite