Chapter 9 concept map Chapter 9 Map — Distributed Trouble at a Glance async net silence drift pause vote order risk two properties break it DISTRIBUTED TROUBLE nothing here is certain Partial failure some parts die Timeouts silence means nothing Clocks skew lies quietly Fencing tokens beat zombies Quorum majority decides LWW danger timestamps misorder Safety, liveness bad never, good someday Verification prove it, then break it Net, clock and paused process create doubt; quorum, fencing and proofs restore certainty.