Distributed Systems 101: the hidden foundation of blockchain everyone ignores think you understand blockchain? most don’t. they think bitcoin is “magic internet money” and ethereum is “the chain for smart contracts.” truth: blockchain is a clever application of distributed systems. if you don’t get distributed systems, you’re memorizing buzzwords. let’s fix that 👇 __________________ what even is a distributed system? imagine a ledger, but everyone keeps a copy. you all message, verify, and agree on updates. no single person controls truth. technically: independent computers (nodes) that appear like one system by passing messages over a network. simple idea. brutally hard engineering. __________________ the core problem blockchain tackles how do thousands of independent computers agree on one truth when some are slow, offline, or malicious? that’s the byzantine generals problem. blockchain’s move: make lying costly, honesty cheap, and coordinate with math + incentives. __________________ the terms you actually need to know - nodes: the peers running the protocol (full nodes / validators). - consensus: how they agree (bitcoin: pow; ethereum: pos). - crash vs byzantine faults: stop responding vs lie/contradict. blockchains assume byzantine. - fault tolerance: tolerate up to f faulty actors; byzantine-safe protocols need 3f+1 total (≥2/3 honest). - state machine replication (smr): all honest nodes apply the same ordered tx → same state. - flp impossibility: in fully async networks, deterministic consensus can’t be guaranteed with even 1 crash → real systems assume partial synchrony or use randomness. - consistency (c): every reader sees the same, latest data after a write. - availability (a): the system always replies to a request (doesn’t hang or error), as long as the node you reached is up. - partition tolerance (p): the system keeps working even if the network splits or drops/delays messages between groups of nodes. - cap theorem: during a network split you can’t have consistency + availability with partition tolerance. public chains choose availability + partition tolerance → eventual consistency (confirmations/finality). - latency: global agreement isn’t instant by design (btc ~10m blocks; eth ~12s slots + epoch finality). __________________ why this matters for blockchains? - decentralization is engineering, not idealism. it removes single points of failure/corruption. - pow/pos aren’t vibes. they answer “how do strangers agree on truth without trust?” - why tx aren’t instant. messages must propagate; conflicts resolve; consensus locks in. you can’t have instant settlement + decentralization + strong security without trade-offs. - resilience by design. many nodes can fail; the network still progresses. __________________ why different chains “feel” different? - bitcoin: prioritizes security + decentralization; probabilistic finality (wait confirmations). - ethereum (pos): BFT-style voting + slashing; deterministic finality once ≥2/3 stake votes (≈ 2 epochs). - solana: proof of history (verifiable time) + tower bft → very low latency; tighter timing + beefier hardware. - sui: narwhal+bullshark (dag) + object model → simple tx skip global consensus; parallelism by design. - aptos: hotstuff-line bft + block-stm for parallel execution; modular pipeline for throughput. __________________ the plot twist start with distributed systems, not “what is a blockchain.” once you see messages → order → state, the magic becomes engineering. __________________ the deep questions to ask now - nakamoto vs BFT: what’s the real difference? - why does ethereum need ≥2/3 honest stake for finality? - why did solana add a cryptographic clock? - why can sui let simple transfers bypass consensus? - what is partial synchrony, and why do most chains assume it? “If I have seen further, it is by standing on the shoulders of giants.” - newton blockchain stands on decades of distributed systems (lamport, lynch, paxos, pbft, hotstuff). 🧵 share if this finally made blockchain click beyond buzzwords. follow me @scrapychian if this was helpful. what do you want me to talk about next? how can i improve so that i can simplify blockchain concepts.