4. Primary-Backup Replication 5. Fault Tolerance: Raft (1) 6. Fault Tolerance: Raft (2) 9. Consistency and Linearizability 12. Distributed Transactions 13. Cache Consistency: Frangipani 15. Optimistic Concurrency Control 18. Cache Consistency: Memcached at Facebook 20. Fork Consistency, SUNDR 21. Byzantine Fault Tolerance 22. Peer-to-peer: Bitcoin 24. Verified Primary/Backup