Chapter 9: Distributed Systems Principles, Consensus & Decentralized Ledger Technology

The hard problems of distributed systems: CAP/PACELC, consensus, clocks and ordering, and distributed transactions.

• The CAP Theorem, PACELC, and Architectural Trade-offs
• Consensus Protocols: Paxos, Raft, Multi-Paxos, and Distributed Locks (Chubby, Redlock)
• Clocks & Ordering: Physical Clocks, NTP, Logical Clocks (Lamport), and Vector Clocks
• Distributed Transactions: Two-Phase Commit (2PC), Three-Phase Commit (3PC), and the Saga Pattern
• Decentralized Systems, Web3 & Blockchain: Merkle-Patricia Tries, PoW/PoS Consensus, EVM Runtimes, P2P Mesh Networks (Libp2p, Kademlia DHT), and DeFi Protocols (AMMs, Oracles)
• References