SOLVED CS550 Homework 5

  1. (5 points) What is view synchronous? What is atomic message?

1. (5 points) What is coordinated checkpointing?

1. (10 points) What is a Byzantine failure? How many replicas are needed to survive a k component fail in Byzantine failure? Why?

1. (10 points) Consider a Web browser that returns an outdated cached page instead of more recent one that had been updated at the server. Is this a failure, and if so, what kind of failure?

1. (10 points) We have stated that totally ordered multicasting using Lamport’s logical clocks does not scale. Explain why.

1. (10 points) In reliable multicasting, is it always necessary that the communication layer keeps a copy of a message for retransmission purposes?
2. (10 points) In the two-phase commit protocol, why can blocking never be eliminated, even when the participants elect a new coordinator?

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